Here - Exoclimes III | The Diversity of Planetary Atmospheres

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PROGRAMME & ABSTRACTS

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General information!

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Programme!!

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List of Participants!

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Abstract of contributions!

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Insights from Solar System planets! ! Terrestrial planets! ! ! ! Super-Earths and hot Neptunes! ! Hot Jupiters: observations! ! ! Hot Jupiters: models! ! ! ! Young giant planets and brown dwarfs!

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Presentation Venue Davos is a winter resort in the East of Switzerland, at 1560 m one of the highest town in the Alps. Its showpiece is the Conference Centre, which hosts the World Economic Forum every year. Exoclimes Previous Exoclimes conferences have taken place in Exeter, UK, in September 2010, and Aspen, CO in January 2012. The objective of these conferences is to bring together specialists of the Earth, Solar System planets and exoplanets to discuss the new field of comparative planetology outside the Solar System. Contact In case of need during the conference, contact the organisers at [email protected] or call +41 77 418 58 12. Emergency numbers in Switzerland are 117 for police, 118 for fire and 144 for ambulance.

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Exploring the Diversity of Planetary Atmospheres Davos 9-14 February 2014

Monday 10th 8:00!

Desk opens

8:50!

Welcome address

Programme

Exoclimes III

Session: Earth-like atmospheres 9:00!

Exotic atmospheres (review): Pierrehumbert

9:40!

A new perspective on the inner edge of the habitable zone: Leconte

10:05! Break 10:30! Paleo-climates (review): Abbot 11:10! Exoplanetary extreme space weather: Cohen 11:35! Terrestrial planet atmospheres in the aftermath of giant impacts: Lupu 12:00 ! Lunch break

Session: Interiors 17:00! Interior-atmosphere interactions (review): Elkins-Tanton 17:40! Earth’s interior dynamics (review): Tackley 18:05! Break 18:20! Magneto-hydro-dynamics: T. Rogers 19:00! Evening break

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Programme

Tuesday 11th Session: Exoplanet observations 8:30!

Exoplanet transit observations (review): Desert

9:10! 9:35!

Characterising exoplanet atmospheres with HST/WFC3: Mandell Revealing distant worlds with ground-based spectroscopy: Stevenson

10:00!

Break

10:30!

Exoplanet eclipse/phase observations (review): Knutson

11:10! ! ! ! ! ! ! ! !

Observation highlights – Ground-based detection of water in hot Jupiters: Birkby Probing the atmosphere of non-transiting planets: Brogi 2D mapping of the eccentric planet HAT-P-2b: de Wit Mapping clouds in exoplanet atmospheres: Demory Measuring the reflection signal of HD 189733b: Evans Atmosphere of exo-Neptune HAT-P-11b: Fraine! Transmission spectroscopy of super-Earth GJ1214b: Kreidberg HST/STIS transmission spectral survey: Nikolov

12:00 !

Lunch break

14:00!

Workshop on transit observations: Sing

Session: Clouds and hazes

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17:00!

Photochemistry (review): Moses

17:40!

Overcoming remote sensing challenges for cloudy atmospheres: Barstow

18:05!

Break

18:20!

Recent advances in exoplanet climate simulations: Showman

19:00!

Evening break

Session: Circulation models 8:30!

Exoplanet circulation models (review): Menou

9:10! 9:35!

Non-hydrostatic, deep-atmosphere hot Jupiter climate models : Mayne Water loss from N2/CO2-atmosphere terrestrial planets: Wordsworth

Programme

Wednesday 12th

10:00! Break Session: Evaporation and energy 10:30! Global energy budgets for terrestrial and gas giant exoplanets: Read 11:10! Models of exoplanet evaporation: Owen 11:35! Enshrouded close-in exoplanets : Haswell 12:00 ! Lunch break

Session: Outer Solar System 17:00! Titan’s atmosphere (review): Mitchell 17:40! Measurement of the atmospheres of Europa, Ganymede and Callisto: Wurz 18:05! Break 18:20! Jupiter’s atmosphere (review): Kaspi 19:00! Evening break

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Programme

Thursday 13th Session: Brown dwarfs and directly-imaged planets 8:30!

Brown dwarf observations (review): Apai

9:10! 9:35!

Results from the “Weather on other worlds” Spitzer campaign : Metchev

Doppler imaging of a nearby cloudy brown dwarf: Crossfield

10:00!

Break

10:30!

Model brown dwarf spectra (review): Barman

11:10!

Connecting low-gravity brown dwarfs and directly-imaged planets: Liu

11:35!

The mid-infrared properties of directly-imaged planets: Skemer

12:00 !

Lunch break

Session: Synthetic spectra

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17:00!

Model exoplanet spectra (review): Fortney

17:40!

Simulated transit spectra of Earth and Jupiter: Irwin

18:05!

Break

18:20!

Poster session

19:00!

Evening break

Session: Atmospheric retrieval 8:30!

Chemical characterisation of super-Earths: Madhusudhan

8:55! A comparison of exoplanet retrieval techniques: Line 9:20! The atmospheres of GJ1214b and GJ436b: Benneke 9:40 ! Discussion

Programme

Friday 14th

10:00! Break Session: Theory 10:30! Helium-dominated atmosphere on Neptune-size GJ436b: R. Hu 10:55! Ionisation regimes structuring planetary atmospheres: Helling 11:20! Ocean transport in the climate of exoplanets around M-dwarf stars: ! Y. Hu 11:40 ! Atmospheric super-rotation: Lewis 12:00 ! Lunch break Session: Earth-like exoplanets 17:00! Climate dynamics (review): Schneider 17:40! Climate and photochemistry of potentially habitable exoplanets: Tian 18:05! Break 18:20! The prospects for characterizing the atmospheres of rocky exoplanets: ! Charbonneau 19:00! Evening break

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Participants

PARTICIPANTS

Dorian! Miquela! Nadine! Suzanne! Yann! David! Daniel! Daniel! Jeremy! Travis! Joanna! Jean-Loup! Jacob! Thomas! Björn! Andrei! Svetlana! Zachory! Jayne! Jasmina! Kimberly! Vincent! Matteo! Carolyn! Matthew! Ben! Ludmila! David! Ofer! Vincent! Nicolas! Ian! Nicolas! Patricio! Mario! Remco! Julien! Laetitia! Brice-Olivier! Jean-Michel! Hannah!

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Abbot ! Abbot ! Afram! Aigrain! Alibert! Amundsen! Angerhausen! Apai! Bailey! Barman! Barstow! Baudino! Bean! Beatty! Benneke! Berdyugin! Berdyugina! Berta-Thompson! Birkby! Blecic! Bott! Bourrier! Brogi! Brown! Browning! Burningham! Carone! Charbonneau! Cohen! Coudé du Foresto! Cowan! Crossfield! Crouzet ! Cubillos! Damasso! de Kok! de Wit! Delrez! Demory! Desert! Diamond-Lowe!

University of Chicago University of Chicago Kiepeneheuer Inst. für Sonnenphysik! University of Oxford University of Bern! University of Exeter! Rensselaer Polytechnic Institute! University of Arizona University of New South Wales! University of Arizona University of Oxford! LESIA, Observatoire de Paris! University of Chicago Ohio State University! California Institute of Technology ! FINCA, University of Turku! Kiepeneheuer Inst. für Sonnenphysik! Massachusetts Inst. of Technology ! Leiden Observatory! University of Central Florida! University of New South Wales! Institut d’Astrophysique de Paris! Leiden Observatory! University of Southern Queensland University of Exeter University of Hertfordshire! CmPA, KU Leuven! Harvard University! Harvard-Smithsonian CfA! Paris Observatory / Bern University Northwestern University! Max Plank Institute for Astrophysics! Dunlap Institute, University of Toronto! University of Central Florida! INAF-Astrophysical Obs. of Torino! SRON / Leiden Observatory! Massachusetts Institute of Technology! University of Liège Massachusetts Institute of Technology! University of Colorado University of Chicago

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Dobbs-Dixon! NYU Abu Dhabi! p. 53 Dorn! University of Bern Dragomir! University of California/LCOGT! p. 33 Drummond! University of Exeter Eggl! IMCCE, Observatoire de Paris! p. 24 Elkins-Tanton! DTM, Carnegie Institution Erwin! University of Arizona! p. 53 Esteves! University of Toronto! p. 43 Evans! University of Oxford! p. 43 Faherty! Carnegie Institution of Washington, DTM Faulk! University of California, Los Angeles! p. 14 Fohring! Durham University ! p. 43 Folini! ETH Zürich Fortney! University of California-Santa Cruz Fraine! University of Maryland! p. 33 Freedman! SETI Institute Fromang! CEA Saclay GarcÌa Muñoz! RSSD, European Space Agency! p. 19 Gibson! European Southern Observatory! p. 43 Gisler! Kiepeneheuer Institut für Sonnenphysik! p. 15 Grenfell! German Aerospace Centre (DLR)! p. 24 Grimm! University of Zurich! p. 53 Guerlet! Laboratoire de Métrologie Dynamique! p. 15 Hall! University of Cambridge! p. 34 Harrington! University of Central Florida! p. 44 Haswell! The Open University! p. 44 Helling! University of St Andrews! p. 59 Heng! University of Bern! p. 54 Hocke! University of Bern Hoeijmakers! Leiden Observatory Homeier! CRAL/ENS-Lyon! p. 59 Hori! National Astronomical Observatory Japan! p. 34 Howard! University of Hawaii Hu! California Institute of Technology! p. 34 Hu! Peking University! p. 25 Iro! Klimacampus - University of Hamburg! p. 54 Irwin! Oxford University! p.16 Isaak! ESTEC, European Space Agency Kammer! California Institute of Technology! p. 35 Kaspi! Weizmann Institute of Science Kataria! University of Arizona! p. 25 Kawahara! University of Tokyo! p. 45 Kedziora-Chudczer University of New South Wales! p.16

Participants

Ian! Caroline! Diana! Benjamin! Siegfried! Lindy! Justin! Lisa! Tom! Jacqueline! Sean! Dora! Doris! Jonathan! Jonathan! Richard! Sebastien! Antonio! Neale! Daniel! John Lee! Simon! Sandrine! Aimee! Joseph! Carole! Christiane! Kevin! Klemens! Jens! Derek! Yasunori! Andrew! Renyu! Yongyun! Nicolas! Patrick! Kate! Joshua! Yohai! Tiffany! Hajime! Lucyna!

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Participants 12

Sara! Flavien! Cevahir! Daniel! Heather! Daniel! Thaddeus! Tommi! Nadia! Laura! Oleksii! Panayotis! Alain! Jeremy! Jae-Min! Emmanuel! Stephen! Michael! Jeffrey! Michael! Joe! Eric! Roxana! Nikku! Jared! Luigi! Avi! Nadejda! Stephen! Nathan! Victoria! Joao! Kristen! Stephen! Stanimir! Alison! Jonathan! Pilar! Caroline! Katie! Julie! Norio! Nikolay! Lisa! Joseph!

Khalafinejad! Hamburg Observatory Kiefer! IAP! p. 60 Kilic! University of Bern! p. 26 Kitzmann! Technical University Berlin! p. 55 Knutson! California Institute of Technology Koll! University of Chicago! p. 36 Komacek! University of Arizona! p. 55 Koskinen! University of Arizona! p. 56 Kostogryz! Kiepeneheuer Inst. für Sonnenphysik p.16 Kreidberg! University of Chicago! p. 36 Kuzmychov! Kiepeneheuer Inst. für Sonnenphysik!p. 60 Lavvas! CNRS (France) Lecavelier! Institut d’Astrophysique deParis! p. 56 Leconte! CITA/LMD! p. 26 Lee! University of Zurich! p. 60 Lellouch! Observatoire de Paris Lewis! The Open University ! p. 17 Line! University of California-SC! p. 61 Linsky! University of Colorado Liu! University of Hawaii! p. 61 Llama! University of St Andrews! p. 45 Lopez! UC Santa Cruz! p. 36 Lupu! SETI Institute! p. 27 Madhusudhan! University of Cambridge! p. 37 Males! University of Arizona! p. 61 Mancini! Max Planck Insitute for Astronomy Mandell! NASA Goddard! p. 46 Marounina! Laboratoire de Planetologie, Nantes! p. 17 Marsden! University of Southern Queensland! p. 27 Mayne! University of Exeter! p. 56 Meadows! University of Washington Mendonca! University of Bern! p.18 Menou! Columbia University Messenger! Massachusetts Inst.of T echnology Metchev! University of Western Ontario! p. 62 Mitchell! University of Californa LA Mitchell! University of Californa LA Montanes-Rodriguez Inst. de Astrofisica de Canarias! p. 18 Morley! University of California-Santa Cruz! p. 62 Morzinski! University of Arizona! p. 62 Moses! Space Science Institute Narita! National Astronomical Obs. Japan! p. 37 Nikolov! University of Exeter! p. 46 Nortmann! Institut für Astrophysik Göttingen! p. 47 O'Rourke! California Institute of Technology! p. 47

Owen! CITA ! Parviainen! University of Oxford! Palle! Instituto de Astrofisica de Canarias! Pierrehumbert!University of Chicago Pont! University of Exeter Popp! Max Planck Institute for Meteorology! Ramirez! Pennsylvania State University Read! University of Oxford! Robinson! NASA Ames Research Center! Rogers! California Institute of Technology! Rogers! University of Arizona Rugheimer! Harvard University Salameh! Max Planck Institute for Meteorology! Schneider! ETH Zürich Schwarz! Leiden Observatory! Shields! University of Washington! Showman! University of Arizona Shporer! Caltech/JPL! Sing! University of Exeter Skemer! University of Arizona! Stevenson! University of Chicago! Tackley! ETH Zürich Tan! Caltech/JPL! Tian! Peking University! Todorov! ETH Zürich! Tremblin! University of Exeter Van Eylen! Aarhus University! Varga! Eötvös Lorand University Vladilo! INAF-Astrophysical Obs. of Torino Wakeford! University of Exeter! Wang! Peking University Wilson! University of Exeter! Woitke! University of St Andrews! Wordsworth! University of Chicago! Wurz! University of Bern! Wyttenbach! University of Geneva! Yan! ESO! Yang! University of Chicago! Zalucha! SETI Institute! Zellem! University of Arizona! Zsom! Massachusetts Institute of Technology!

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Participants

James! Hannu! Enric! Raymond! Frédéric! Max! Ramses! Peter! Tyler! Leslie! Tamara! Sarah! Josiane! Tapio! Henriette! Aomawa! Adam! Avi! David! Andrew! Kevin! Paul! Zhihong! Feng! Kamen! Pascal! Vincent! Tamas Norbert! Giovanni! Hannah! Yuwei! Paul Anthony! Peter! Robin! Peter! Aurélien! Fei! Jun! Angela! Robert ! Andras!

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TALKS/POSTERS ABSTRACTS* INSIGHTS FROM SOLAR SYSTEM PLANETS Gloomy planets: overcoming remote sensing challenges for cloudy atmospheres Joanna K. Barstow — University of Oxford For most known planets, our only knowledge about their atmospheres comes from remote sensing and spectroscopic analysis. There are often multiple, degenerate atmospheric states that could produce the observed spectra, and usually more complex atmospheric models result in greater numbers of permitted atmospheric states. The inclusion of clouds in an atmospheric model increases its complexity. The size of the cloud parameter space, the nature of the condensate, size of condensate particles, number density and location within the atmosphere all influence spectral features. Recent analyses of the best-studied extrasolar planets, such as HD 189733b and GJ 1214b, indicate that clouds are as ubiquitous outside the solar system as they are inside it. Their probable presence on these planets can no longer be ignored, but the quality and spectral coverage of remote sensing data for exoplanets and the outer planets in our own solar system limits our ability to draw conclusions about their nature. We are left with a vast, underconstrained model parameter space to explore. In addition, the presence of uncharacterised clouds in planetary atmospheres can prevent us from placing constraints on temperature structure and chemistry due to model degeneracy, or can result in mistaken conclusions based on incorrect assumptions. I explore the significance of different cloud properties for reflection, emission and transmission spectra of planetary atmospheres, including examples such as the extremely detailed characterisation of the H2SO4 cloud on Venus, the hints of enstatite clouds on HD 189733b, and the possibility of Titan-like hydrocarbon hazes on GJ 1214b. I will present suggestions for a framework to explore cloudy solutions for data-poor planets. The structure of the Intertropical Convergence Zone over a wide range of atmospheric circulations simulated with an idealized GCM! Sean Faulk — UCLA ! One of the most prominent features of the Earth's large-scale circulation in low latitudes is the intertropical convergence zone (ITCZ), where tropical precipitation is concentrated in a relatively narrow latitudinal band. Given that small changes in the ITCZ can result in large local changes in precipitation, factors that control its structure and position have been widely investigated in the literature. In other planetary settings such as Mars and Titan, it has been argued that an ITCZ can migrate significantly off the equator into the summer hemisphere, perhaps even to the summer pole. The dynamical, thermodynamical and radiative mechanisms controlling seasonal ITCZ migrations has only begun to be explored. Exploration of the ITCZ behavior in a wide parameter space is important to understand the fundamental dynamics of the Earth's ITCZ and also to characterize climates on other planets. Here, we examine the structure of the ITCZ over a wide range of atmospheric *

Arranged by topic in six categories. See the list of participants (p.10) to find page of specific abstract 14

circulations with an idealized General Circulation Model (GCM), in which an atmospheric model with idealized physics is coupled to an aquaplanet slab ocean of fixed depth and the top-of-atmosphere insolation is varied seasonally. A broad range of circulation regimes is studied by changing the thermal inertia of the slab ocean, the planet rotation rate and radius while keeping the seasonal cycle of insolation fixed. The climates of Earth, Mars and Titan will be discussed in this context, and implications for classifying exoplanet climates will be drawn. A search for hot water vapor in the atmosphere of Venus during the 2012 transit Daniel Gisler — Kiepenheuer-Institut für Sonnenphysik We have observed the Venus transit in 2012 using the Scatter-free Observatory for Limb Active Regions and Coronae (SOLARC), located on the summit of Haleakala, Maui. The SOLARC is a 45 cm off-axis Gregorian telescope. This telescope design minimizes scattered light, that is critical for photon-limited observations. The data has been collected with the Optical Fiber Imaging Spectralpoarimeter (OFIS). Our goal is to search for water vapor lines absorbing solar light passing through the Venusian atmosphere and evaluate the sensitivity of our spectropolarimetric technique to detect water and other constituents in atmospheres of transiting exoplanets. Here we present the data and analyze Stokes I, Q, U spectra extracted from the solar disk and the Venus limb and night side. We estimate limits on the water vapor partial pressure and compare these with measurements by space missions and probes. Development of a new Global Climate Model of Saturn's stratosphere Sandrine Guerlet — Laboratoire de Météorologie Dynamique, Paris! Recent observations of Saturn’s stratospheric thermal structure and composition have revealed new phenomena: an equatorial oscillation in temperature, reminiscent of the Earth's Quasi-Biennal Oscillation ; strong meridional contrasts of hydrocarbons ; a warm “beacon” associated with the powerful 2010 storm. Those signatures cannot be reproduced by 1D photochemical and radiative models and suggest that atmospheric dynamics plays a key role. This motivated us to develop a complete 3D General Circulation Model (GCM) for Saturn, based on the LMD’s hydrodynamical core, to explore the circulation, seasonal variability, and wave activity in Saturn's atmosphere. In order to closely reproduce Saturn's radiative forcing, a particular emphasis was put in obtaining fast and accurate radiative transfer calculations. Our radiative model uses correlated-k distributions and spectral discretization tailored for Saturn's atmosphere. We include an internal heat flux, ring shadowing and both tropospheric and stratospheric aerosols. Firstly, we will present a comparison of temperature fields obtained with this new seasonal, radiative equilibrium model to that inferred from Cassini/CIRS observations. Even in the absence of dynamics, our model qualitatively reproduces the overall meridional temperature gradient between the summer and the winter hemispheres in the lower stratosphere except in the equatorial region, where the temperature structure is governed by the dynamical equatorial oscillation. Our model can also reproduce the “temperature knee” observed around 200 mbar, which is caused by heating at the top of the tropospheric aerosol layer.

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Finally, we will show GCM simulations coupling the 3D dynamical core to this radiative model, and discuss the large-scale stratospheric circulations driven by the radiative forcing. Simulated transit spectra of Earth and Jupiter Patrick Irwin — University of Oxford In recent years, increasingly accurate measurements have been made of the transit spectra of hot Jupiters, such as HD 189733b, from the visible through to mid-infrared wavelengths. These have been modelled to derive the likely atmospheric structure and composition of these planets. As measurement techniques improve, the transit spectra of super-Earths such as GJ 1214b are becoming increasingly accessible, allowing model atmospheric states to be fitted for this class of planet also. While it is not yet possible to constrain the atmospheric states of solar system-like planets such as the Earth or Jupiter from such measurements, it is hoped that this might one day become practical; if so, it is of interest to determine what we might infer from such measurements. In this work we have constructed atmospheric models of Earth and Jupiter from 0.2 - 15 microns that are consistent with ground-based and satellite observations. From these models we calculate the primary and secondary transit spectra (with respect to the Sun) that would be observed by a remote observer, many light years away, and also directly imaged spectra, assuming that this one day becomes technically feasible. From these spectra we test how well optimal estimation retrieval models can determine the atmospheric states and compare these with the “ground truths” in order to assess: a) the inherent difficulty in using transit spectra observations to observe solar system-like targets; b) the relative merits of primary versus secondary transit spectra; and c) the optimal wavelength coverage, resolutions and sensitivities required to retrieve useful information about the atmospheres of such planets. D/H ratios in methane in the atmosphere of giant planets and Titan! Lucyna Kedziora-Chudczer — University of New South Wales We present observations of the GNIRS/GEMINI high resolution spectra at 1.58 and 2.03 microns for the giant planets of our Solar System and Saturn's moon Titan. We fitted the atmospheric absorption spectra of these objects using the VSTAR line-by-line radiative transfer modelling to estimate the D/H ratios from deuterated methane in both bands. Deuteration of the outer planets can be used not only as a diagnostic of initial conditions in the solar nebula during formation of giant planets but also to help to determine the location at which planets accreted the bulk of their mass. We estimated that based on D/H ratio derived for Titan, the Saturnian system formed close to its current location, which has implication on previously proposed migration theories. Vertical structure of gas-planet atmospheres inferred from methane bands Nadiia Kostogryz — Kiepenheuer-Institut für Sonnenphysik Visible and near infrared spectra of the Jovian planets in the Solar system are dominated by methane absorption features. These bands are very useful for determining the vertical cloud structure of planetary atmospheres as was proposed by Morozhenko (1984) and implemented for the Uranus atmosphere by Kostogryz (2013). The fact that the diffusely reflected radiation is formed at different effective depths in the atmosphere allows to constrain the vertical cloud structure. The cloud height and opacity strongly influence the 16

geometric albedo of the planet and, therefore, are needed for constructing a realistic atmosphere model. Here we extend this method to exoplanetary atmospheres. We simulate methane spectra from atmospheres with various cloud structure and analyze them as observed spectra to infer the cloud properties. We investigate limits on the spectral resolution and signal-to-noise ratio for this technique to be applied to hot Jupiter atmospheres. Atmospheric super-rotation in solar system and extra-solar planetary atmospheres Stephen R. Lewis — The Open University, UK Super-rotation is a common phenomenon in solar system planetary atmospheres. Out of the four substantial atmospheres possessed by solid bodies in the solar system, the slowly rotating planet, Venus, and moon, Titan, are both well-known to have atmospheres that rotate on average substantially more quickly than does the solid surface underneath. The more rapidly rotating planets, Mars and Earth, have much weaker global super-rotation, but both can exhibit time-varying prograde jets near the equator which rotate more rapidly than the local surface. Atmospheric super-rotation is not restricted to planets with solid surfaces and shallow atmospheres. Cloud-tracking observations of the gas giants Jupiter and Saturn show that they both possess rapid prograde equatorial jets and hence exhibit local super-rotation. Simplified global circulation models of extra-solar planets, including representations of hot Jupiters and Earth-like planets rotating at different rates, can also show sustained super-rotating equatorial jets in different dynamical regimes. In the extra-solar planet cases in particular, the quantitative results are highly sensitive to model parameters. In each case the detailed mechanism, or combination of mechanisms, which produces the super-rotating jets might vary, but all require longitudinally asymmetric motions, waves or eddies, to transport angular momentum up-gradient into the jets. The mechanism is not always easy to diagnose from observations and requires careful modelling. We review both observations of solar system planets and recent global circulation model results, combined in the case of Mars and Earth in the form of atmospheric reanalyses by data assimilation, together with simplified extra-solar planet simulations. Generation and early evolution of Titan's atmosphere Nadejda Marounina! — LPGN! Titan is the only satellite of the Solar System with a substantial atmosphere (1.47 bar), which is primarily composed of N2 (~98%) and CH4 (~ 2%). The low Ar/N2 ratio measured by the Huygens probe in Titan's atmosphere indicates that the nitrogen was incorporated as NH3 and possibly other nitrogen-bearing easily condensible compounds. Therefore, a conversion mechanisms is needed to explain the present-day N2-dominated atmosphere. Different conversion scenarios have been proposed (endogenic conversion, atmospheric impact chemistry...). Here we evaluate a scenario recently proposed by Sekine et al. (2011) involving an impact-induced conversion of NH3, stored as hydrate in Titan’s icy crust, and subsequent degassing of N2 during the Late Heavy Bombardement. Using the scaling laws derived from their experimental study, we computed the balance between the degassed N2 and the erosion of the atmosphere by impact (Shuvalov 2009) for an impact population characteristic of the Late Heavy Bombardment (LHB). Our numerical model include a parameterized description of the radiative and thermodynamical equilibria of the atmosphere (Lorenz et al. 1999). 17

Our results show that whatever the size of NH3-enriched crustal reservoirs, N2 production by impacts is not able to counterbalance the atmospheric loss by impact erosion for realistic size distribution of impactors. We show that in order to preserve a substantial atmosphere on Titan after the LHB, an initially massive atmosphere (5-times present-day mass) is required. Our results indicate that a very efficient conversion mechanism should have occurred during the accretion and shortly after to produce such a massive N2 atmosphere. During accretion the impact heating may have been strong enough to melt the superficial icy layer and form an ocean, which volatile species outgassed and form a primitive atmosphere (Monteux et al., in prep). We are currently developing a new numerical model of a liquid-vapor equilibrium for various initial oceanic composition to investigate how a massive atmosphere may be generated during the satellite growth and how it may then evolve toward a composition dominated by N2. More generally, our model may address how atmosphere may be generated in water-rich objects, which may be common around other stars. Simulating the atmospheric circulation of Venus! Joao Mendonca — University of Bern! Venus is the most Earth-like astronomical object in terms of size, mass and orbital properties in our Solar system. Despite these similarities, Venus is slowly rotating in the opposite direction, has the most massive atmosphere of the terrestrial planets and is covered by an opaque and highly reflective cloud layer. These differences are important to drive the Venus atmospheric circulation to a very distinct regime from Earth's, with strong atmospheric super-rotation and a variety of other atmospheric dynamic features such as the observed large-scale wave patterns, which are not well understood. I will summarise the main efforts of the last three decades to simulate the Venus atmospheric circulation using general circulation models, and the most likely mechanisms driving the atmosphere to the actual observed circulation. Recently in Lebonnois et al. 2011, it was shown that Venus general circulation models that use simplified representations of heating, cooling and friction processes, obtained very distinct results, which raised concerns about the intrinsic numerical errors and assumptions in the routines that solve the dynamical behaviour of the flow. These problems and the latest results by modern models, which use more physically-based parameterizations (Lebonnois et al. 2010 & Mendonca 2013) will be discussed and compared. In our new model (Mendonca 2013), the Venus atmospheric circulation in the cloud region is well represented. Additionally, the results are sensitive to some radiative properties near the surface and also to the amount of clouds. Despite the progress, there are still modelling difficulties which I will address in this work. I will also analyse and describe the main implications that the Venus climate modelling has in the exploration of exo-climes. Transmission spectra of Jupiter from Ganymede during eclipses! Pilar Montañès-Rodrìguez — Instituto de Astrofìsica de Canarias ! Transit spectroscopy data from several hot Jupiter planets are already being collected from several space and ground-based instruments. And more temperate Jupiter-like planets are expected to be characterized in the near future. In this framework, an investigation of the spectral features of Jupiter, in transmission, as if it were observed from a distant star, can greatly contribute to the modeling efforts of such planetary atmospheres. Here, we present observations of the near-infrared transmission spectrum of Jupiter with LIRIS at the WHT, 18

as reflected from Ganymede's surface during an eclipse. When Ganymede is in the umbra of Jupiter, only sunlight that has traversed the Jupiter atmosphere is illuminating its surface. By taking observations of Ganymede before and during an eclipse, we are able to retrieve Jupiter's atmospheric fingerprints. Disk-integrated reflection light curves of planets! Antonio Garcìa Muñoz — ESA-RSSD, ESTEC The light scattered by a planet atmosphere contains valuable information on the planet’s composition and aerosol content. Typically, the interpretation of that information requires elaborate radiative transport models accounting for the absorption and scattering processes undergone by the star photons on their passage through the atmosphere. I have been working on a particular family of algorithms based on Backward Monte Carlo (BMC) integration for solving the multiple-scattering problem in atmospheric media. BMC algorithms simulate statistically the photon trajectories in the reverse order that they actually occur, i.e. they trace the photons from the detector through the atmospheric medium and onwards to the illumination source following probability laws dictated by the medium’s optical properties. BMC algorithms are versatile, as they can handle diverse viewing and illumination geometries, and can readily accommodate various physical phenomena. As will be shown, BMC algorithms are very well suited for the prediction of magnitudes integrated over a planet’s disk (whether uniform or not). Disk-integrated magnitudes are relevant in the current context of exploration of extrasolar planets because spatial resolution of these objects will not be technologically feasible in the near future. I have been working on various predictions for the disk-integrated properties of planets that demonstrate the capacities of the BMC algorithm. These cases include the variability of the Earth’s integrated signal caused by diurnal and seasonal changes in the surface reflectance and cloudiness, or by sporadic injection of large amounts of volcanic particles into the atmosphere. Since the implemented BMC algorithm includes a polarization mode, these examples also serve to illustrate the potential of polarimetry in the characterization of both Solar System and extrasolar planets. The work is complemented with the analysis of disk-integrated photometric observations of Earth and Venus drawn from various sources. Comparative global energy budgets for the climates of terrestrial and gas giant planets Peter Read — University of Oxford The weather and climate on Earth are generally determined by the amount and distribution of incoming solar radiation. This must be balanced in equilibrium by the emission of thermal radiation from the surface and atmosphere, but the precise routes by which incoming energy is transferred from the surface, through the atmosphere and back out to space are important features that characterize the current climate. This has been analysed by several groups over the years, based on combinations of numerical model simulations and direct observations of the Earth’s climate system. The results are often presented in schematic form (Trenberth et al. 2009) to show the main routes for the transfer of energy into, out of and within the climate system. Although relatively simple in concept, such diagrams convey a great deal of information about the climate system in a compact form, and are especially valuable pedagogically at school and undergraduate level. Such an approach has not so far been adopted in any systematic way for other planets of the Solar System, let alone beyond, although quite detailed climate models of several 19

planets are now available, constrained by many new observations and measurements. Here we analyse the global transfers of energy within the climate systems of a range of terrestrial planetary bodies within the Solar System, including Mars, Titan and Venus, as simulated by relatively comprehensive numerical circulation models. These results will then be presented in schematic form for comparison with the “classical” global energy budget analysis of Trenberth et al. for the Earth, highlighting the important similarities and differences. We also consider how to extend this approach towards other Solar System and extra-solar planets, including Jupiter, Saturn and hot Jupiter exoplanets. A ~0.1 bar Rule for Tropopause Temperature Minima in Thick Atmospheres of Planets and Large Moons Tyler Robinson — University of Washington Tropopause temperature minima are fundamental for understanding planetary atmospheric structure. Inversions in the stratospheres of Earth, Jupiter, Saturn, Titan, Uranus, and Neptune lead to temperature minima that, remarkably, all occur near 0.1 bar, despite very different insolation, atmospheric composition, gravity, and internal heat flux. We have explored this common 0.1 bar tropopause using an analytic 1-D radiative-convective model. We find that tropopause temperature minima always lie in the radiative regime, above the radiative-convective boundary. Thus, the shared 0.1 bar tropopause arises from the common physics of radiative transfer. Model fits to solar system worlds show that the gray infrared optical depth where the tropopause minimum occurs is ~0.1. Furthermore, the gray infrared optical depths at a pressure of 1 bar are typically of order a few. These, along with a commonly used power-law scaling between pressure and optical depth, set the tropopause pressure at ~0.1 bar. Moving beyond the solar system, we show that the typical gray infrared optical depth of the tropopause minimum is ~0.1 for a wide range of plausible atmospheric compositions. This optical depth marks the transition into an upper region of an atmosphere that is very transparent to thermal radiation. Here, shortwave absorption can dominate the temperature profile and, thus, create an inversion and corresponding temperature minimum. These findings imply that the common 0.1 bar tropopause levels seen in the solar system atmospheres are more universal. Thus, we hypothesize that many exoplanets will possess a 0.1 bar tropopause temperature minimum. Measurement of the atmospheres of Europa, Ganymede, and Callisto Peter Wurz — Physics Institute, University of Bern! The regular Jovian satellites are believed to be formed at the end of Jupiter's formation epoch, from the collisional accretion of solids originating in the Solar Nebula, and captured in a disk orbiting around the planet. The solids taking part to the formation of the satellites therefore originate from the initial protoplanetary disk, and have probably experienced lower temperature and pressure conditions as has the material incorporated in Jupiter, and their chemical composition has been probably less altered. By measuring the composition of the Jovian satellites, it is therefore possible to set constraints on the chemical composition of building blocks of planets and satellites, and ultimately on the thermodynamical conditions in the Solar Nebula. The Particle Environment Package (PEP) suite has been selected for the JUICE mission of ESA, which contains instruments for the comprehensive measurements of electrons, ions and neutrals. One of the instruments is the Neutral and Ion Mass spectrometer instrument (NIM). NIM is a time-of-flight neutral gas and thermal ion mass spectrometer 20

optimised for exospheric investigations. NIM will measure the composition of the exospheres of Europa, Ganymede, and Callisto. Various physical processes are acting on the surfaces of Jupiter’s icy moons to promote material from the surface into the exosphere. These are thermal desorption (sublimation), photon stimulated desorption, ioninduced sputtering, and micro-meteorite impact vaporisation, with sputtering being the most important surface release process. Sputtering releases all species present on the surface more or less stoichiometrically into the exosphere, allowing deriving the chemical composition of the surface from these measurements. However, the chemical composition of the surface is modified by the bombardment of energetic electrons and ions, and ultraviolet radiation, which has to be accounted for in the chemical analysis. High-resolution and high-SNR transmission spectrum of Earth’s atmosphere obtained from a lunar eclipse! Fei Yan — European Southern Observatory & National Astronomical Observatories, Chinese Academy of Sciences! With the rapid developments in the exoplanet field, more and more terrestrial exoplanets are being detected. Characterising their atmospheres using transit observations will become a key datum in the quest for detecting an Earth-like exoplanet. The atmospheric transmission spectrum of our Earth will be an ideal template for comparison with future exo-Earth candidates. By observing a lunar eclipse, which offers a similar configuration to that of an exoplanet transit, we have obtained a high resolution and high signal-to-noise ratio transmission spectrum of the Earth’s atmosphere. We will present the transmission spectrum together with our 1-D atmospheric spectral model. From the model-fit, the column densities of the various atmospheric species are calculated. Some intersting results from this work are discussed, such as the forwardscattered sunlight, the oxygen isotopes, the souces of NO2. Extreme Planetary Classes in Our Own Solar System: The Atmospheric Circulation of Pluto and Triton! Angela Zalucha — SETI Institute! Pluto and Triton (Neptune's largest moon) are often called “sister worlds” due to their nearly identical atmospheric composition, size, and temperature. While the bulk temperature and composition have been constrained by ground-based stellar occultation observations and the Voyager 2 flyby of Neptune, the circulation patterns at all scales are still not known due to the difficulty in observing wind remotely. Pluto and Triton, or “ice dwarfs”, are quite unusual compared with other known planetary bodies, in that efficient methane absorption in the atmosphere creates at strong temperature inversion (temperature increasing with height) near the surface that has been dubbed the stratosphere. Such a configuration is extremely stable and prevents vertical motion, which impacts flow in the other directions as well (for example, Hadley cells, ubiquitous on terrestrial planets and perhaps super-Earths, are not expected to exist). Moreover, much like Mars, it is thought that these sister worlds have a volatile cycle where the main atmospheric constituent (here molecular nitrogen) condenses and sublimates throughout the year, even to the point of atmospheric collapse. Within the past few years, there has been a surge of interest in Pluto's global circulation patterns. This problem has posed a challenge unprecedented from other planetary bodies. First, Pluto's year is about 250 Earth years, requiring long simulation times.Second, Pluto's atmosphere and surface are thought to be strongly coupled radiatively, requiring both a 21

sophisticated atmosphere and surface model. The properties (emissivity, configuration of ices, thermal inertia, and total surface ice inventory) of Pluto's surface are not well constrained. Various groups have used different general circulation models (GCMs) to predict the atmospheric circulation of Pluto. I will discuss results from the MIT Pluto GCM, which after several years of atmosphere-only studies (e.g. Zalucha and Michaels 2013) is now coupled to a sophisticated surface model.

TERRESTRIAL PLANETS Maximum planet size for habitability Yann Alibert! — University of Bern The conditions that a planet must fulfill in order to be habitable are not precisely known. However, it is comparatively easier to define conditions under which a planet is very likely not habitable. Finding such conditions is moreover important as it can help to select, in an ensemble of potentially observable planets, which ones should be observed in more details for characterization studies. Assuming, as in the case of the Earth, that the presence of a C-cycle is a necessary condition for long-term habitability, we derive, as a function of the planetary mass, a radius above which a planet is likely not habitable. For this, we compute the maximum radius a planet can have in order to fulfill two constraints: surface conditions compatible with the existence of liquid water, and no ice layer at the bottom of a putative global ocean. We demonstrate that, above a given radius, these two constraints cannot be met. For this, we compute internal structure models of planets, using a 5-layer model (core, inner mantle, outer mantle, ocean and atmosphere), for different masses and composition of the planets (in particular Fe/Si ratio of the planet). Our results show that for planets in the Super-Earth mass range (1-12 Mearth), the overall maximum size that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation when computing the gas envelope structure. Remote detection of biosignatures on Earth-like planets Svetlana Berdyugina — KIS, Freiburg Life on Earth is aware of light polarization and makes good use of it for its survival and growth. In all cases, it is the solar light that is reflected, processed and analyzed by life forms, and the same circumstances are expected to exist on all habitable planets. Photosynthesis, in particular, is very likely to arise on another planet and can produce conspicuous biosignatures. Recently, it was demonstrated that polarized reflected light can be detected from exoplanetary atmospheres. We focus now on identifying biological polarization effects, e.g., selective light absorption or scattering by biogenic molecules. This helps to enhance the reliability of other biomarkers for distant detection of life which can be contaminated by non-biological sources. Here we present a laboratory study of reflected light polarization from various terrestrial plants and non-biological samples (rocks and sands). We use these measured reflection spectra to synthesize polarized spectra of Earth-like planets with various contributions from the land, photosynthetic organisms, ocean, atmosphere, and clouds. We estimate the required photometric and polarimetric sensitivity to detect such planets in habitable zones of nearby stars. 22

Weather on strange new worlds: Large scale atmospheric dynamics on tidally locked terrestrial planets around an M dwarf star Ludmila Carone — KU Leuven, Center for mathematical Plasma-astrophysics ! It is likely that the first habitable extrasolar planet with an atmosphere will be discovered around an M star. Indeed, several terrestrial planets have already been discovered around such stars. These planets will probably be tidally locked. Therefore, the climate dynamics of a terrestrial exoplanet — even in the habitable zone — might be very different from the Earth. Firstly, the rotation will be slower and we would therefore not expect mid-latidude cyclones but rather a barotropic atmosphere. Secondly, the temperature varies rather with longitude than with latitude leading to circulation between the dark and cold hemisphere. Because there are many unknowns with exoplanets, in particular with terrestrial exoplanets, we decided to explore the dynamics of a greenhouse atmosphere on a tidally locked planet with a medium-size parameter study. We used an idealized global threedimensional dry circulation model (GCM) with an idealized forcing, adopting MITgcm (http://mitgcm.org). As a first step, different day-night temperature differences, rotation periods, time scales for radiation and surface friction, and surface pressures were investigated. The emerging large scale dynamics of the atmosphere was compared with previous studies and with observations and models of Venus and Titan; the latter being the closest analogues in the Solar System. Our goal is to identify, on the one hand, features that are robust against parameter change — like superrotation and Hadley-like circulation cells — and, on the other hand, to investigate climate patterns that vary strongly with different assumptions: like the surface wind and temperature, and large scale vortices. This not only broadens our understanding about the different mechanisms at play in atmospheres, but may also lead to a better coupling between observations of transiting terrestrial exoplanets and atmospheric models. The Prospects for Characterizing the Atmospheres of Rocky Exoplanets! David!Charbonneau — Harvard University ! The coming decade brings the promise of direct spectroscopic characterization of the atmospheres of rocky planets orbiting other nearby stars. The most accessible planets will be those that orbit M-dwarfs, owing to the diminutive stature, low-luminosities, and preponderance of these stars. This talk will present a quantitative evaluation of the prospects for this path informed by the most recent data: I will begin by presenting an analysis of the complete Kepler dataset to determine the rate of occurrence of such planets. I will combine this with the catalog of nearby stars to evaluate the likely distance to the closest transiting systems, and the likely characteristics of the stellar host. I will then address the sensitivity of the NASA TESS Mission, the MEarth transit survey, and other ongoing projects to detect such objects. I will conclude by presenting the likely signal-tonoise, resolution, and wavelength coverage that should be delivered by the James Webb Space Telescope, the Giant Magellan telescope, and other large ground-based telescopes. Using the technique of transmission spectroscopy, some of these telescopes should be able to investigate such planetary atmospheres beginning as early as 2018, provided the community has identified the targets. The goal of this presentation will be to leave the audience with a quantitative understanding of what we can, and cannot, hope to measure in this time frame, and thus to assist them in directing their research efforts accordingly. 23

Exoplanetary Extreme Space Weather Ofer Cohen — Harvard-Smithsonian CfA ! Exoplanetary research is driven by the ultimate goal of defining whether life can exist beyond the Earth and the solar system, while recent searches for exoplanets are focused increasingly on detecting rocky, Earth-like planets around M-dwarf stars, which are by far the most numerous type of star in the Universe. The “planet habitability” problem is a cross-disciplinary topic where commonly, a planet is defined as habitable if its surface temperature allows water to exist in a liquid form. However, there are other factors that can impact planet habitability. M-dwarf stars are very active magnetically and their X-ray and ultraviolet radiation in their habitable zones is much higher than we experience near the Earth. The physics of the solar atmosphere, the interplanetary environment, and the upper atmospheres of planets in the solar system, including the Earth, is governed by the radiation environment, electromagnetic forces, and the interaction between charged particles and magnetic fields. In particular, the atmosphere of the Earth is shielded from the intense radiation in space and from the solar wind by the Earth’s intrinsic magnetic field. Here we present a set of numerical models, which were developed to study solar system objects, and their application to exoplanetary, M-dwarf systems. These models include detailed physical processes that are known to be important for solar system bodies, but are commonly neglected in the context of exoplanets. Specifically, we investigate the role of the planetary magnetic field in shielding the planetary atmosphere from erosion by the extreme space environment in which it resides. Our study estimates what planetary field strengths are necessary for protection from the caustic space environment of M-dwarfs, and demonstrates how coronal mass ejections from M-dwarfs affects the planet’s magnetospheres, and how much atmosphere is likely to be stripped away in the larger events. Defining Habitable Zones in Gravitationally Interacting Systems! Siegfried Eggl — IMCCE Observatoire de Paris! Calculating the extent of liquid-water habitable zones around main sequence stars becomes challenging for systems with more than two gravitationally interacting bodies, since the evolution of planetary orbits has to be taken into account. Given the recent progress in determining liquid-water habitable zones within binary star systems we present a generalized methodology to identify habitable-zone boundaries in multistar and multiplanet systems. Planning follow-up Space Missions searching for Atmospheric Spectral Biosignatures from a sample of potentially habitable Earth-like Exoplanets! John Lee Grenfell — Planetary Research Inst. DLR Berlin! Next generation missions which aim at the atmospheric characterization of rocky extrasolar planets could provide initial information on the amounts of carbon dioxide and water molecules in the atmospheres of hot to temperate Super-Earths. Follow-up studies may be needed however to search for (likely weaker) atmospheric biosignature signals from a sample of Super-Earths. Until now, most studies have focused on the effects of atmospheric carbon dioxide and water upon planetary climate, hence (potential) habitability. There is, however, potentially additional information held in such data. On 24

Earth, atmospheric carbon dioxide is strongly affected by life itself (e.g. vegetation enhances weathering) so that on a “dead Earth” the atmospheric carbon dioxide would be significantly higher than on its living counterpart. This could represent an additional selection procedure for follow-up studies searching for biosignatures from a sample of habitable planets. A difficult challenge when applying such a technique is to constrain abiotic processes affecting atmospheric carbon dioxide e.g. hydrology, geochemistry and outgassing. Life itself may also regulate the carbon-silicate cycle, hence stabilize climate, but the extent and means of this process if it exists are not well known. Forty years ago a cluster of studies focused on “live” and “dead” Earths in the context of the Gaia hypothesis and the effect on the carbon cycle. There is now a need to revisit this work with newgeneration models but with a focus on exoplanetary habitability. In this work we discuss possible selection procedures for follow-up studies which search for biosignatures given a sample of rocky Super-Earths with known atmospheric carbon dioxide and water abundances. We apply a radiative column model to calculate consistent CO2 and H2O abundances for dead Earth scenarios. The role of ocean heat transport in climates of tidally locked exoplanets around Mdwarf Stars Yongyun Hu! — Peking University! The distinctive feature of tidally locked exoplanets is the very uneven heating by stellar radiation between the dayside and nightside. Previous work has focused on the role of atmospheric heat transport in preventing atmospheric collapse on the nightside for terrestrial exoplanets in the habitable zone around M-dwarfs. In the present paper, we carry out the first simulation with a fully coupled atmosphere-ocean general circulation model (AOGCM) to investigate the role of ocean heat transport in climate states of tidally locked habitable exoplanets around M-dwarfs. Our simulation results demonstrate that ocean heat transport substantially extends the area of open water along the equator, showing a lobster-like spatial pattern of open water, instead of an “eyeball”. For sufficiently high-level greenhouse gases or strong stellar radiation, ocean heat transport can even lead to complete deglaciation of the nightside. Our simulations also suggest that ocean heat transport likely narrows the width of M-dwarfs’ habitable zone. This study provides the first demonstration of the importance of exo-oceanography in determining climate states and habitability of exoplanets. Updates to the SPARC/MITgcm: Modeling the atmospheric circulation of terrestrial exoplanets! Tiffany Kataria — University of Arizona As the detection and characterization of exoplanets moves toward smaller planets in the super-Earth and terrestrial regimes, atmospheric circulation modeling continues to play an important role in helping to understand ground-and space-based observations of their atmospheres. These models must range from planets with thick atmospheric envelopes and no surface (for super Earths) to planets with thinner atmospheres and rocky surfaces (for terrestrial exoplanets). To that end, we present a summary of terrestrial planet updates to our model, the Substellar and Planetary Atmospheric Radiation and Circulation (SPARC) model, which couples the MIT General Circulation Model with a two-stream, nongrey implementation of the multi-stream, non-grey radiative transfer code developed by Marley and McKay (1999). These updates include an implementation of moist and dry convective schemes, a boundary layer scheme, and a surface energy balance which self25

consistently calculates the ground temperature. We present early results from studies looking at the role of clouds on the dynamics and habitability of terrestrial exoplanets orbiting M-dwarfs. Using these models, we will identify fundamental dynamical mechanisms that drive their atmospheres and constrain their thermal structures, which will inform future observations of transiting terrestrial exoplanets, particularly at secondary eclipse. Modeling of Habitable Planets - the Underlying Atmospheric Dynamics Cevahir Kilic! — University of Bern! Instrumentation to detect new planets develops continually and enabled the scientific community to characterize exoplanets in terms of physical parameters, such as size and mass, as well as identify possible atmospheres. Furthermore, the CHEOPS satellite program will provide the possibility for an improved characterization also in terms of habitability of exoplanets. The increasing number of newly detected planets raises issues of possible other habitable worlds. To investigate the atmospheric dynamics of habitable planets, we use a hierarchy of general circulation models (GCMs). In a first step, we carry out these simulations using a three-dimensional atmospheric GCM of intermediate complexity, the so-called Planet Simulator. For this study, sensitivity simulations varying different basic parameters of the planet are performed to explore the range of habitability. Each simulation is carried out over 30 model years. In doing so, we have modified gravity, radius, sidereal day, atmospheric composition, distance to the star, and obliquity of the ecliptic. These simulations uses an Earth-like environment (e.g., Earth land mask), which allows us to compare our investigations with Earth observations. The range of surface temperatures determines the habitability of a planet. Our simulations show, inter alia, that an increase in radius leads to a reduction of the global mean temperature. We also find an impact on the amplitude of the seasonality given by the gravity of the planet. The difference between maximum and minimum temperature is enhanced with increasing gravity. Additionally, the variation of the gravity changes the atmospheric structure: an increased gravity leads to a more stable atmosphere above 700 hPa and to generally stronger wind fields and lower surface temperatures on the planet. Furthermore, basic dynamical features such as the number of jet streams will be assessed in the sensitivity simulations. The next steps also include a model adaption with different land masks (e.g., aqua-planet). A new perspective on the inner edge of the habitable zone: 3D modeling of runaway greenhouse processes on Earth like planets Jeremy Leconte — LMD (Paris) / CITA (Toronto) Because current exoplanets detection methods are biased toward shorter-period orbits, most planets discovered to date have a higher equilibrium temperature than the Earth. If water is available at the surface, the amount of water vapor is expected to increase as the planet warms, enhancing, in turn, the atmospheric greenhouse effect. It has been shown that, above a certain critical insolation, this destabilizing greenhouse feedback can "runaway" until all the oceans are evaporated. It has also been suggested that warming may sufficiently increase stratospheric humidity to cause oceans to escape to space before the runaway greenhouse occurs. However, the value of the critical insolations triggering these processes remain uncertain because they have so far been evaluated with unidimensional models that cannot account for dynamical effects and cloud 26

feedback that are key stabilizing features of planetary climates. Understanding and modeling these processes is thus critical to accurately determine the extent of the "Habitable Zone" around other stars. We present results from a 3D global climate model specifically developed to describe hot, extremely moist atmospheres to quantify Earth like planets climate response to an increased insolation. In contrast with previous studies, we find that clouds have a destabilizing feedback on the long term warming. However, subsident, unsaturated regions created by the Hadley circulation have a stabilizing effect that is strong enough to defer the runaway greenhouse limit to higher insolation than inferred from 1D models. Because of these unsaturated regions, the stratosphere remains cold and dry enough to hamper atmospheric water escape, even at large fluxes. Finally, we will discus the implications of these results for Venus early water history and the extent of the habitable zone around low mass stars when the rotation of the planet can be tidally synchronized. Terrestrial planet atmospheres in the aftermath of giant impacts! Roxana Lupu — SETI Institute! The final assembly of terrestrial planets is now universally thought to have occurred through a series of giant impacts, such as Earth's own Moon-forming impact. After the impact the surface of the surviving planet can remain hot for millions of years, making it potentially detectable by direct imaging surveys. Here we explore the atmospheric structures and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres derived from vaporized rock material. The atmospheric chemistry is computed self-consistently for compositions reflecting either the bulk silicate Earth (BSE, including the crust, mantle, atmosphere and oceans) or Earth's continental crust (CC). We compute atmospheric profiles for surface temperatures ranging from 1000 to 2200 K, surface pressures of 10 and 100 bar, and surface gravities of 10 and 30 m/s2. Our calculations using extensive line lists bring a significant improvement over previous models, but still do not include cloud formation and aerosol opacities. We find that the post-giant-impact atmospheres are dominated by H2O and CO2, while the formation of CH4, and NH3 is quenched due to short dynamical timescales. Other important constituents are HF, HCl, NaCl, and SO2. Estimates including photochemistry and vertical mixing show atmospheric enhancements in sulfur-bearing species, particularly SO2, which produces strong spectral features. Estimated luminosities for post-impact planets, although lower than predicted by previous models, show that the hottest post-giant-impact planets will be detectable with the planned 30 m-class telescopes. Finally, we use the models to describe the cooling of a post-impact terrestrial planet and briefly investigate its time evolution. We find that the cooling timescale for post-giant impact Earths ranges between 105 and 106 years, where the slower cooling is associated with the planet going through a runaway greenhouse stage. The impact of stellar winds on exoplanetary magnetospheres S.C. Marsden — University of Southern Queensland The habitable zone of an exoplanet is traditionally defined by the range of orbital distances where planetary surface temperatures are expected to allow for liquid water. However, given that stellar winds can erode planetary atmospheres even when a magnetosphere is present, it is proposed that considerations of planetary habitability include stellar wind 27

pressure.The Bcool project is an international collaboration studying the magnetic fields of solar-type stars and whose results can be used for stellar wind studies. Using a simple wind model we show that an exoplanet like the present-day Earth would generally need to orbit outside the traditional habitable temperature zone of many solar-type stars to maintain the size of its magnetosphere. However, planets orbiting within the classical temperature habitable zone of solar-type stars should possess magnetospheres that although compressed, are likely to protect the planet's atmosphere and hence allow for the planet to be habitable. An aqua planet under strong solar forcing! Max Popp — Max Planck Institute for Meteorology A modified version of the general circulation model ECHAM6 is used to investigate the impact of increased total solar irradiance (TSI) on an aqua planet on a present-day Earthlike orbit. We find that the present-day Earth-like climate destabilizes for a TSI between 1.06 and 1.08 times the present-day Earth value (S0). The aqua planet does not, however, go into a Runaway Greenhouse, but attains a new steady state with global-mean seasurface temperatures exceeding 335 K. This warm state is characterized by a low meridional temperature gradient, a weak meridional circulation without polar cells, a moist stratosphere and convection-dominated cloud formation. As the TSI is further increased, the planet remains in the same regime of warm steady states for TSIs of at least up to 1.2 S0, because the cloud albedo increases as well, and balances the increased forcing. In these states, the volume mixing ratio of water vapor in the upper atmosphere may attain values as large as 0.015. This large mixing ratio exceeds the “Moist Greenhouse” limit (Kasting et al. 1993) and suggests that a planet in such a warm state would hence be subject to a rapid loss of water. Climate dynamics of a coupled Aquaplanet Josiane Salameh — Max Planck institute for Meteorology The idea behind an Aquaplanet, an idealized configuration of the current Earth with all the landmasses removed, is not recent. However, most of the research is conducted with stand-alone atmospheric models. Thus, the originality behind considering the coupled Aquaplanet setup, highlights the ocean's impact and allows us to directly interpret the fundamental processes and feedbacks between ocean and atmosphere without any land interference. As for the few coupled Aquaplanet studies lately conducted on General Circulation Models (GCM), they showed an extreme disparity regarding the final climate state. The range of states discovered lies between a warm climate qualified with a lack of sea-ice formation and a cold climate where sea-ice extend at the poles. Then, the existence of three equilibrium states was verified while integrating the same GCM from different random initial conditions. The climate of a coupled Aquaplanet remains an open question. Therefore, our task is to analyze the atmospheric-oceanic circulations of a coupled Aquaplanet while contributing to this discrepancy in previous results. The simulations are executed on “ICON”, based on an icosahedral triangular grid. Effects of rotation on Hadley cell's magnitude and extent, winds distribution and others were already theoretically discussed and numerically tested. In order to achieve a higher physical understanding of the Earth rotation rate and its effect on 28

the global circulation features, especially the ocean, our future goal is to consider variable rotation rates in our coupled Aquaplanet setup. The Effect of Host Star Spectral Energy Distribution on Planetary Climate Aomawa Shields — University of Washington! Planetary climate can be affected by the interaction of the host star spectral energy distribution with the wavelength-dependent reflectivity of ice and snow. We have explored this effect with a hierarchy of models. Results from both one-dimensional radiative transfer and energy balance models and a three-dimensional general circulation model indicate that terrestrial planets orbiting stars with higher near-UV radiation exhibit a stronger icealbedo feedback. We found that ice extent is much greater on a planet orbiting an F-dwarf star than on a planet orbiting a G- or M-dwarf star at an equivalent flux distance, assuming fixed CO2 (present atmospheric level on Earth). The surface ice-albedo feedback effect becomes less important at the outer edge of the habitable zone for main-sequence stars, where the maintenance of surface liquid water requires high atmospheric CO2 concentrations. We show that 3-10 bar of CO2 will entirely mask the climatic effect of ice and snow, leaving the outer limits of the habitable zone unaffected by the spectral dependence of water ice and snow albedo. However, less CO2 is needed to maintain open water for a planet orbiting an M-dwarf star than would be the case for hotter mainsequence stars. We also explore the sensitivity of climate hysteresis to spectral energy distribution, and examine how changes in planetary rotation rate and atmospheric composition affect our results. Marine Boundary Layer Clouds and their Interaction with the Large-scale Atmospheric Circulation: An Idealized-GCM Study Zhihong Tan! — California Institute of Technology / ETH Zurich Cloud feedback is one of the central uncertainties in climate modeling, and the short-wave radiative feedback of marine boundary layer (MBL) clouds is the most significant contributor to these uncertainties. We have incorporated a physically motivated eddy diffusivity/mass flux closure for convective turbulence coupled to a probabilistic cloud scheme in an idealized aquaplanet GCM to develop improved turbulence and cloud parameterizations and to study and constrain the physical mechanisms giving rise to cloud feedbacks. Subtropical MBL clouds are observed in simulations with the idealized GCM. We study their response to changes in the longwave optical depth and in the ocean heat flux to determine the sign and magnitude of MBL cloud feedback over a wide range of climates. We compare our results with previous modeling and observational studies, such as the reported dependence of the MBL cloud fractions on the lower troposphere stability. We discuss the mechanisms underlying the MBL cloud feedback and the degree to which they can be expected to be robust, as well as the interaction of MBL processes with the large-scale atmospheric circulation. Climate and Photochemistry of Known Potentially Habitable Exoplanets Feng Tian — Tsinghua University! Several potentially habitable planets are known today. What are the environments like on them? Are they inhabited? What are the potential signatures of life on them? These are important scientific questions for the coming decade(s). Photochemistry is important for 29

the climate on exoplanets by providing important species affecting radiation. On the other hand, climate may pose important constraints on atmospheric composition, based on which different schemes of photochemistry can perform. In this work we will discuss the interplays between exoplanet climate and atmospheric composition and photochemistry, focusing on potentially habitable exoplanets such as HD40307g and the GJ667C planets. Water loss from terrestrial planets with N2/CO2 atmospheres! Robin!Wordsworth! — University of Chicago! The initial volatile content delivered to terrestrial planets during accretion is most likely highly variable, with many planets receiving significantly more than Earth today possesses. Understanding how later processes such as photolysis-driven H2O loss affect planetary evolution is therefore vital to constraining the range of possibilities for both the early Solar System and for many recently discovered low-mass exoplanets. Here we discuss a range of calculations we have performed to study the dependence of water loss rates on a wide range of planetary parameters. We show through a combination of simple analysis and numerical climate models (1D and 3D) that the non-condensing atmospheric component plays a fundamental role in controlling water loss via regulation of the stratospheric cold trap. While CO2 can increase H2O transport to the high atmosphere over a small range of mixing ratios by increasing surface temperature, thermodynamic constraints and cooling of the middle/upper atmosphere act as a bottleneck on escape in other circumstances. The differing relationships of total stellar luminosity and stellar XUV with time for G-stars places strong limits on H2O loss rates for planets like Earth, although escape can reach higher values for planets with surface liquid water around M-stars. Because the carbon cycles of planets with ocean-covered surfaces are likely to be fundamentally different from that of Earth, our results have important implications for the likely surface and atmospheric characteristics of super-Earth exoplanets in the habitable zone. Oceanic Circulation of Tidally Locked Terrestrial Planets! Jun Yang — University of Chicago! A fully coupled oceanic-atmospheric general circulation model is modified to simulate the climate of tidally locked terrestrial planets. A central issue to be examined is to identify the determining factors of oceanic circulation and its associated heat transport in both zonal and meridional directions. In this study we will examine five planetary parameters: ocean depth, land-sea distribution, rotational period (equaling to orbital period), planetary radius, and gravity. All these simulations show an eastward current along the equator, transporting heat from dayside to nightside, and a meridional overturning circulation (MOC) in each hemisphere, transporting heat from tropics to high latitudes. The equatorial current is driven by the combined effect of surface wind streeses and Rossby waves in the ocean which transport eastward momentum from high latitudes to the equator. The MOC is driven by salinity and/ or temperature contrasts between low and high latitudes. The salinity contrast results from sea ice formation at high latitudes which releases salt to the ocean, and from sea ice melting at low-latitude ice margins which decreases the salinity there. The strengths of the oceanic circulation and heat transport are signifcantly influenced by the five planetary parameters. We will further present how these parameters work.

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Towards the Minimum Inner Edge Distance of the Habitable Zone Andras Zsom — Massachusetts Institute of Technology! We explore the minimum distance from a host star where an exoplanet could potentially be habitable in order not to discard close-in rocky exoplanets for follow-up observations. We find that the inner edge of the Habitable Zone for hot desert worlds can be as close as 0.38 AU around a solar-like star, if the greenhouse effect is reduced (low relative humidity), and the surface albedo is increased. We consider a wide range of atmospheric and planetary parameters such as surface pressure, relative humidity, CO2 mixing ratio, surface gravity, etc. We argue that if the dominant mode of precipitation is rain, the potentially habitable region is maximized on the dry planet. Based on this argument, we estimate that relative humidity levels of 1% or more can be sufficient to maintain a liquid water cycle. If the surface pressure is too low (~0.1 bar), the water loss timescale of the planet is too short to support life. If the surface pressure is too high (~100 bars), we show using atmospheric circulation arguments, that the day-night side temperature difference on slow rotators is too small to enable an active water cycle. Intermediate surface pressures (~1-10 bars) can provide suitable conditions for a water cycle independent of the planetary rotation period. We additionally find that the water loss timescale is influenced by the atmospheric CO2 level, because it indirectly influences the stratospheric water mixing ratio. We also show that the expected transmission spectra of hot desert worlds are similar to an Earth-like planet. Therefore, an instrument designed to identify biosignature gases in an Earth-like atmosphere can also identify similarly abundant gases in the atmospheres of dry planets.

SUPER-EARTHS AND HOT NEPTUNES The Atmospheres of GJ1214b and GJ436b: A Comprehensive Retrieval Study Based on Unprecedented Data from Two Large-Scale HST Campaigns Bjørn! Benneke — California Institute of Technology ! In this talk, we present the scientific interpretation for two unprecedented HST WFC3 campaigns to observe the transmission spectra of the warm exo-Neptune GJ436b and the warm super-Earth GJ1214b. We report statistically robust constraints on the atmospheric gas composition as well as the cloud properties such as cloud composition, cloud top altitude, and particle size distribution. Our main result for GJ1214b is that the observations require the presence of high-altitude clouds at high significance, independent of the atmospheric composition and mean molecular mass. We investigate the full range of physically plausible cloud properties that may explain the observations. For GJ436b we find that high-altitude clouds could similarly explain the observed flat transmission spectrum, suggesting that a similar cloud formation mechanism may be at play in the two planets. Alternatively, we suggest the intriguing possibility that GJ436b hosts an atmosphere which is strongly metal-enriched compared to the gas and ice giants in our solar system. The atmospheric constraints are obtained using a novel self-consistent inversion framework that combines the observational data with our prior understanding of atmospheric physics and chemistry in a statistically robust manner. The new framework makes full use of all information at hand and identifies the full range of scenarios that are both physically plausible and in agreement with the data. We describe the merits of this 31

new inversion framework for the interpretation of atmospheric spectra of both exoplanets and Solar System planets. How Do Mini-Neptunes Migrate? Zachory Berta-Thompson — Massachusetts Institute of Technology! To understand an exoplanet, we need to know how it got where it is today. Because it transits a very nearby, very small star, the exoplanet GJ1214b is a useful laboratory for studying the physics of planets near the fuzzy boundary between super-Earths and subNeptunes. However, little is known about how GJ1214b migrated to its current close-in orbit. Was it scattered wildly inward and later tidally circularized, as many hot Jupiters appear to have been? Or was it coaxed in smoothly and gently, as seems to be the case for the compact, coplanar, small-planet systems uncovered by Kepler? To address this conundrum, we search for and analyze recurrent starspot occultations in closely-spaced transit light curves of GJ1214b taken with the Magellan, Gemini, and Hubble telescopes. We use these spot occultations to constrain the relative orientation of the planet’s orbit to the host star’s spin axis, which can be used to distinguish among possible scenarios for the migration history of the planet. This analysis bears not only on the one particularly useful GJ1214b system, but also on the processes that may shape many of the abundant close-in, low-mass, low-density exoplanets that populate our Galaxy. Water Cycling between Ocean and Mantle: Super-Earths need not be Waterworlds Nicolas Cowan — Northwestern University Large terrestrial planets are expected to have muted topography and deep oceans, implying they should be entirely covered in water, so-called waterworlds. Quantitatively, a planet ten times the mass of Earth is not expected to have exposed continents unless it has a water mass fraction less than 3x10^-5, roughly ten times drier than Earth. Waterworld climate is predicted to be less stable than that of planets with exposed continents. Water is partitioned, however, between a surface reservoir, the ocean, and an interior reservoir, the mantle. Plate tectonics transports water between these reservoirs on geological timescales. Degassing of melt at mid-ocean ridges and serpentinization of oceanic crust are mediated by sea-floor pressure, providing a stabilizing feedback on longterm ocean volume. Motivated by Earth's approximately steady-state deep water cycle, we develop a two-box model of the hydrosphere and derive steady-state solutions to the water-partitioning on terrestrial planets. Since hydrostatic pressure is proportional to gravity, super-Earths with a deep water cycle will tend to store most of their water in the mantle. We conclude that tectonically active terrestrial planets with H2O mass fractions less than 3x10-3 will have both oceans and exposed continents. Transiting planets around nearby M dwarfs: updates from the APACHE Project Mario! Damasso — University of Padova Across the Alps, just few hundreds km from Davos as the crow flies, a search for transiting, small-size planets orbiting M dwarfs is in progress since July 2012: the APACHE Project (A PAthway toward the Characterization of Habitable Earths). APACHE is a survey “made in Italy” carried out as a collaboration between the Astronomical Observatory of the Autonomous Region of Aosta Valley and INAF-Torino Astrophysical Observatory, which will last five years and collect a huge database of photometric data. It uses five identical, 32

automatic 400mm telescopes to observe thousands of carefully selected nearby red dwarfs. Nearby, bright M dwarfs are optimal targets as host stars for transiting planets which can be extensively followed up to analyze their atmospheres, as demonstrated by the case of the extrasolar planet GJ 1214b. We present the results of the first observing season for several dozens of cool stars, including detailed simulations aimed at estimating the sensitivity of APACHE to transiting planets of different sizes. Moreover, we will discuss the results obtained for a sample of stars which have been also monitored spectroscopically with HARPS-N@TNG in the framework of the Large National Program GAPS. In the spotlight: small planets transiting bright stars! Diana!Dragomir — UC Santa Barbara/Las Cumbres Observatory Global Telescope The Kepler transit survey has resulted in the discovery of more than a dozen super-Earth planets. Super-Earths are of particular interest in exoplanet research because they constitute a class of objects which are not represented in our Solar System, though statistics from Kepler and radial velocity surveys suggest they are relatively common around other stars. Moreover, these planets can theoretically have a wide range of densities and therefore compositions which we have only very recently begun to explore observationally. While studies of super-Earth hosting systems based on Kepler photometry have contributed significantly to our understanding of these objects, follow-up observations of these planets' atmospheres prove difficult or impossible to carry out with existing instruments due to the faintness of most of the stars in the Kepler field. In order to better understand the nature of this class of planets, we must focus on super-Earths transiting bright stars (allowing for higher-precision observations) and/or small stars (leading to deeper transits more amenable to transmission spectroscopy measurements). I will focus on 55 Cnc e and HD 97658b, the two currently known transiting super-Earths which fall in the former category. The 55 Cnc system has been observed with the MOST space telescope for a total of 70 days over a period of three years. I will present results based on the analysis of these data, including constraints on the secondary eclipse (and hence the albedo) of 55 Cnc e, and discuss implications for the planet's atmospheric composition. I will also present MOST photometry of HD 97658b and describe the current state of knowledge of this low-density super-Earth's structure and composition, including a report on our efforts to probe its atmosphere with the HST and Spitzer. Atmospheric Composition of the ExoNeptune HAT-P-11b! Jonathan D.! Fraine!— University of Maryland We present new observations of the transiting exo-Neptune HAT-P-11b from a joint HST and warm Spitzer program to measure the transmission spectrum of its thick atmosphere. Our data cover a wide span of wavelength space, including warm Spitzer IRAC 3.6 & 4.5 micron photometry and Hubble WFC3 1.1 - 1.7 micron spectroscopy from our observations, as well as Kepler's optical photometry centered at 632nm. Our WFC3 spectroscopic observations are among the first using HST's new spatial scanning mode for optimised signal-to-noise spectroscopy. In addition, HAT-P-11 is one of the most active planet-hosting stars; observations of HAT-P-11b's atmosphere therefore allow us to shed light on the role that stellar activity may play in shaping the atmospheric chemistry of Neptune-sized planets. We use the Kepler photometry to model and remove the effects of the stellar activity during and surrounding our warm Spitzer transit observations. Our 33

combined observations provide constraints on the existence of clouds or hazes and the atmospheric chemistry at the day-night terminator. Neptunes in the Noise: Improved Precision in Exoplanet Transit Detection! Aimée E. Hall — Institute of Astronomy, University of Cambridge! SuperWASP is an established, highly successful ground-based survey that has already discovered over 80 exoplanets around bright stars. It is only with wide-field surveys such as this that we can find planets around the brightest stars, which are best suited for advancing our knowledge of exoplanetary atmospheres. However, complex instrumental systematics have so far limited SuperWASP to primarily finding hot Jupiters around stars fainter than 10th magnitude. By quantifying and accounting for these systematics up front, rather than in the post-processing stage, the photometric noise can be significantly reduced. In this paper, we present our methods and discuss preliminary results from our reanalysis. We show that the improved processing will enable us to find smaller planets around even brighter stars than was previously possible in the SuperWASP data. Such planets could prove invaluable to the community as they would potentially become ideal targets for the studies of exoplanet atmospheres. Water content and hydrogen-rich atmoshperes of sub-/super-Earths orbiting cool stars Yasunori Hori — National Astronomical Observatory of Japan! Over the past five years, close-in low-mass exoplanets orbiting cool stars has increased in number rapidly. Recently, transmission spectra in a planetary atmosphere during a primary eclipse have enabled us to explore the atmospheric compositions of super-Earths. Habitat environment and formation histories of close-in planets are closely related to volatile inventories in their atmospheres such as water and hydrogen. We have examined the water content and the amount of hydrogen-rich atmospheres of sub-/super-Earths around cool stars, performing 1,000 Monte Carlo simulations of planet formation. We have found that super-Earths with 1-30 Earth-mass are likely to possess more than 20-30wt% water mantles surrounded by thick H2-rich blankets: 0.1-20wt% H-He atmospheres for 1-10 Earth-mass planets inside 0.1AU, such as GJ 1214b, and more than 50wt% for larger planets inside 1AU like GJ 436b. We have also shown that dry/wet sub-Earths with 0.1-1 Earth-mass inside 1AU end in naked ones with less than 1wt% H-He atmospheres. Our results predict that sub-Earths in a habitable zone are wet but have almost no primitive atmosphere, while super-Earths near/in the zone, for example, GJ 581d, GJ 667Cc, and GJ 163c, contain abundant water and sufficient H2-rich atmospheres. Moderately-wet planets with 0.001-1wt% water similar to the Earth, i.e., land planets, are either a small fraction of sub-Earths near the inner edge or non-migrating planets near 1AU. In any case, water worlds of sub-/super-Earths in a multiple-planet system are common around cool stars. Helium-Dominated Atmosphere on Neptune-Sized Exoplanet GJ 436b Renyu Hu — California Institute of Technology! The composition of the atmosphere on exoplanet GJ 436b, the most characterized Neptune-sized exoplanet to date, has been a long-standing puzzle. The dayside emission 34

of the planet shows that its atmosphere is poor in methane and rich in carbon monoxide and carbon dioxide, yet both equilibrium chemistry and disequilibrium chemistry models predict most carbon to be in the form of methane for the temperature of the planet. This contradiction is further intensified by the planet's large radius and low mean density, which requires the planet to have an extensive gas envelope. Here we provide an explanation for both the planet's emission spectrum and the planet\s radius. We propose that the atmosphere of GJ 436b is mainly composed of helium. We have used a recently established photochemistry-thermochemistry kinetic-transport model to compute the molecular composition of the thick atmosphere on GJ 436b, with the helium versus hydrogen ratio and the carbon and oxygen abundances as free parameters. The temperature of the atmosphere is self-consistently computed using grey-atmosphere approximation from the composition governed by disequilibrium chemistry. We find that a helium-dominated atmosphere with hydrogen elemental abundance less than 3% by number will have carbon dioxide and carbon monoxide as the main forms of carbon and little methane, and thus lead to spectral features consistent with observations. Such an atmosphere has mean molecular mass of ~4, only 2 times greater than that of a hydrogendominated atmosphere, and therefore the helium-dominated atmosphere can be extended enough to meet the mass-radius constraint of the planet. To form such a helium-dominated atmosphere on a Neptune-sized exoplanet, we suggest that efficient hydrodynamic atmospheric loss should have occurred in the early history of the planet. Hydrodynamic escape has removed most of the hydrogen from gas accretion, and also removed some of the helium, which resulted in the enrichment of helium in the planet's gas envelope. If this mechanism is correct, one would expect helium-dominated atmospheres to be common on Neptune and sub-Neptune sized exoplanets around M dwarfs. Exploring the Relationship Between Exoplanet Mass and Atmospheric Metallicity! Joshua Kammer — California Institute of Technology! Studies of hydrogen-dominated planetary atmospheres in our solar system have shown that as core mass fraction increases, so does atmospheric metallicity. This hypothesis holds true for Uranus and Neptune, as these planets have atmospheres more enriched relative to solar metallicity (30-40x) as compared to Jupiter (3x). Though these planets' bulk densities are comparable to many detected exoplanets in the same size range, it remains an open question whether the metallicities of exoplanet atmospheres also follow a similar trend. One way to explore the correlation between planet mass and atmospheric metallicity is by characterization of secondary eclipse emission spectra. For cooler exoplanets (T < 1000 K) atmospheric models predict that carbon chemistry should be dominated by CH4 rather than CO for an atmosphere of solar metallicity. Increasing the atmospheric metallicity will suppress the amount of methane and enhance CO, as proposed by Moses et al. (2013) to explain GJ 436b's unusually low methane-to-CO ratio. Here we present results and analysis of Spitzer 3.6 and 4.5 μm secondary eclipse observations of seven exoplanets with masses ranging from sub-Neptune to super-Jupiter in size. Although they do not provide unique constraints on all the relative abundances of water, methane, CO, and CO2, these measurements can reveal empirical trends in CH4-toCO ratios for cooler exoplanets in this size range, and test the correlation between exoplanet mass and atmospheric metallicity.

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Constraining the degeneracy of Super-Earth phase curve measurements Daniel D.B. Koll — University of Chicago! Thermal phase curve measurements of transiting exoplanets offer direct insight into how efficiently their atmospheres redistribute heat. These measurements already indicate distinct atmospheric circulation regimes on hot Jupiters, and stand to be a prime tool for remotely characterizing Super-Earth atmospheres. However, for Super-Earths the efficiency of atmospheric energy transport depends on a large number of difficult-toconstrain parameters (atmospheric composition & mass, presence/absence of condensible gases, surface type etc.). Assuming imperfect knowledge of these parameters, how degenerate are phase curve measurements? Can we use phase curve measurements to robustly distinguish between different atmospheric scenarios, or do we need additional information from, e.g., transit spectroscopy? To answer this question, it is necessary to comprehensively map out how the atmospheric energy transport depends on a large number of atmospheric parameters. To make the problem computationally tractable we non-dimensionalize the primitive equations and equations of grey-gas radiative transfer and find a reduced set of non-dimensional numbers that govern the atmospheric dynamics. We present simulations with an idealized dry global climate model (GCM) to demonstrate the utility of this approach. We also present results on how the atmospheric energy transport varies over the phase space spanned by these non-dimensional numbers, focusing on the relative roles of dynamics, radiation and uncertain model parameterizations. Transmission Spectroscopy of the Super-Earth Archetype GJ 1214b! Laura! Kreidberg — University of Chicago! Super-Earths, exoplanets intermediate in size between Earth and Neptune, are among the most prevalent planets in the Galaxy. Revealing the composition and formation histories of these common objects requires atmospheric characterization. I will present the results of an intensive observational campaign to study the atmosphere of the super-Earth archetype GJ 1214b. We observed 15 transits of the planet with the Hubble Space Telescope in the near-infrared, yielding the most precise exoplanet transmission spectrum measurement ever obtained in this wavelength range. Our measurements definitively distinguish between clear, high mean molecular weight atmospheric models and models with high-altitude clouds. I will also discuss preliminary results of a Gemini program to measure the transmission spectrum in the blue optical. Understanding Kepler's Super-Earths and Sub-Neptunes: Insights from Thermal Evolution and Photo-Evaporation! Eric Lopez — UC Santa Cruz NASA's Kepler mission has discovered a large new population of super-Earth and subNeptune sized planets. Although we have no analogous planet in our own solar system, such planets are incredibly common. Understanding the nature and formation of systems of these planets is one of the key challenges for theories of planet formation. We use models of thermal evolution and photo-evaporation to constrain the structure, composition, and evolution of low-mass planets. Over time Neptune-like planets with large H/He envelopes can be transformed into rocky super-Earths. We show that differences in mass loss history provide a natural explanation for many features of the Kepler multi-planet systems, such as large density contrast between Kepler-36b and Kepler-36c. For the 36

broader population of Kepler planets, we find that there is a threshold in bulk planet density, mass, and incident flux above which no low-mass transiting planets have been observed. We suggest that this threshold is due to XUV-driven photo-evaporation and show that it is well reproduced by our evolution models. Chemical Characterization of Super-Earths: Interiors, Atmospheres, and Formation Conditions Nikku! Madhusudhan — Yale University Recent advances in exoplanetary science are leading to unprecedented observations of super-Earths. The observed masses, radii, and temperatures of super-Earths provide constraints on their interior structures, geophysical conditions, as well as their atmospheric compositions. Some of the most recently detected super-Earths span a wide gamut of possible compositions, from super-Mercuries and lava planets to water worlds with thick volatile envelopes. In this work, we report joint constraints on the interior and atmospheric compositions of several super-Earths and discuss their possible formation scenarios using new and comprehensive hybrid models of their interiors, non-gray atmospheres, and formation conditions. Our model constraints are based on the masses and visible radii, as well as the latest infrared measurements of transmission and emission spectrophotometry where available, in addition to revised estimates of the stellar parameters. We will present a comparative analysis of several transiting super-Earths currently known and will discuss in detail two super-Earths (GJ 1214b and 55 Cancri e) which have atmospheric data available and which represent two distinct end members in the thermo-chemical phase space of super-Earth conditions. We will also discuss the implications of our results for the diversity of geochemical and geophysical conditions on super-Earths. We will conclude with comments on new observational, theoretical, and experimental efforts that are critical to detailed characterization of super-Earths. Multi-Color Simultaneous Transit Photometry of Planets around Cool Host Stars Norio Narita — National Astronomical Observatory of Japan Transmission spectroscopy is a powerful method to investigate planetary atmospheres for transiting exoplanets. For ground-based large (6-10 m class) telescopes, multi-object spectroscopy and high dispersion spectroscopy have shown successful results for this purpose. For smaller (1-2 m class) telescopes, multi-color simultaneous transit photometry provides an alternative and efficient way for transmission spectroscopy. In this talk, we focus on such multi-color simultaneous transit photometry for planets around cool host stars, including GJ1214, GJ3470, and WASP-80. We present some observational results taken in 2011 and 2012 seasons (e.g., Narita et al. 2013a, Narita et al. 2013b, Fukui et al. 2013) and preliminary results for data taken in 2013 season. Characterizing the Demographics of Exoplanet Bulk Compositions Leslie Rogers — California Institute of Technology The Kepler Mission has discovered thousands of sub-Saturn-sized transiting planet candidates. Using planet interior structure models, we constrain the bulk compositions of the more than 50 known sub-Saturn-sized transiting planets with measured masses. Our model considers fully differentiated planets comprised of up to four layers: an iron core, a silicate mantle, a water mantle, and a gas envelope. We calculate the planet interior 37

structure by integrating the coupled differential equations describing an evolving selfgravitating body, employing modern equations of state for the iron, silicates, water, and gas. For any individual planet, a wide range of compositions is consistent with the measured mass and radius. We consider the planets as an ensemble, and discuss how thermal evolution, mass loss, and observational biases sculpt the observed planet massradius-insolation distribution. Understanding these effects is crucial for constraining the demographics of small planet bulk compositions and for extracting signatures of the planet formation process from the accumulating census of transiting planets with dynamical confirmation. Ground-based search for the transit of Alpha Cen Bb Aurelien Wyttenbach — Geneva Observatory In late 2012, a planet with a minimum mass of 1.13 earth mass may have been detected around Alpha Cen B with the HARPS spectrograph. With a 3.2 days orbit, the planet has a 10% transit probability. However, with an expected transit depth of ~100 ppm, searching for the transit is challenging, especially from the ground because of correlated noise in the light curves. The extreme brightness of Alpha Cen B, and the close separation from Alpha Cen A (4") complicate the task further. We have developed and tested a method designed to beat down correlated noise, while coping with the brightness and duplicity of the Alpha Cen system, using high-resolution spectroscopy. Here, we present the first light curve of Alpha Cen B obtained using this method during one night of observations with UVES at the VLT.

HOT JUPITERS: OBSERVATIONS Spectrophotometry with SOFIA: First results! Daniel!Angerhausen — Rensselaer Polytechnic Institute Over the past decade the transit method (measuring the small, wavelength-dependent variation in flux as an exoplanet passes in front of or behind its parent star) has produced a number of exciting characterization results. The NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA), a 2.5-meter infrared telescope on board a Boeing 747-SP, has a specific and unique phase space for these extremely precise time-domain spectrophotometric observations at IR wavelengths: It operates in the right wavelength regime, where the planet's black-body temperature peaks and contrast ratios between star and planet improve. The airborne observatory is able to avoid most of the perturbing variation of atmospheric trace gases that produce the dominant source of noise for ground-based observations in the near-infrared. These telluric molecules are also the species of interest in the exo-atmospheres. The SOFIA telescope is operating at much lower temperatures (~240 K) than ground-based telescopes (~273 K). Therefore thermal background contributions, the dominant noise source for transit observations at wavelengths longer than 3 micron, will be significantly reduced. The mobile platform SOFIA can observe time-critical events, such as the rare transits of long-period planets, under optimized conditions. After the end of Spitzer and until the start of the JWST mission, SOFIA will be the only observatory capable of NIR spectrophotometry of exoplanet atmospheres beyond 1.7 micron (the upper limit for HST after the last upgrade) 38

at an altitude where the impact of variable telluric absorption is small enough for high precision observations of the same molecules also present in exoplanet atmospheres. Here we present SOFIA's unique advantages in comparison to ground- and space-based observatories in this field of research and present the very first spectrophotometric exoplanet observations that were or will be conducted in SOFIA’s cycles 1 and 2. Characterisation of Exoplanets using Polarization! Jeremy Bailey — University of New South Wales! Light reflected from the atmospheres of extrasolar planets will be polarized, and the detection and measurement of that polarization provides a means of characterising the atmospheres that provides complementary information to that from spectroscopy. At UNSW we are building a new instrument with the aim of measuring polarization in the combined light of a star and hot Jupiter planet, and thus detecting the polarization of the planet. We have also incorporated polarization capability into our atmospheric modelling code VSTAR. Polarization is particularly sensitive to the presence of atmospheric clouds and hazes. I will describe our current progress on these developments, and discuss the potential of such techniques for the study of exoplanet atmospheres. Polarimetric detection and characterization of hot Jupiters! Andrei! Berdyugin — FINCA, University of Turku, Finland The light scattered in planetary atmospheres is linearly polarized perpendicular to the scattering plane. In general, when the planet rotates around the parent star, the scattering angle changes and the Stokes parameters Q and U of linear polarization vary. If the orbit is close to circular, two peaks per orbital period are observed. The observed polarization variability exhibits therefore the orbital period of the planet and reveals the inclination, eccentricity, and orientation of the orbit. Due to proximity to the star, hot giant planets with short orbital periods ("hot Jupiters") may develop extended peculiar atmospheres and halos which effectively scatter the light in the blue spectral region. This can give rise to a degree of polarization detectable with the currently existing modern polarimeters. Parameters of this polarization, e.g., wavelength dependence, are defined by physical conditions in the upper layers of the planetary atmosphere. Thus, polarimetry of hot "blue Jupiters" in combination with other methods of observations may be used to draw conclusions on properties of their atmospheres. Here we present new polarimetric observations of several hot Jupiters, both transiting and non-transiting, in three bands: blue, green, and red. These data were obtained with two instruments: (1) our new Double Imaging Polarimeter (DIPol-2) at the 60cm KVA telescope on La Palma, routinely providing polarimetric accuracy of 10-5, and (2) the FORS polarimeter at the VLT, ESO, with the maximum accuracy of 10-4. We analyze these data using our model calculations and infer planet orbit parameters and atmosphere reflectivity. We compare our results with measurements of the secondary eclipses of hot Jupiters. Detecting water in hot Jupiter atmospheres with high-resolution ground-based spectroscopy! Jayne!Birkby — Leiden Observatory The robust determination of the chemical make-up of exoplanet atmospheres is crucial to understanding their structure, formation, and evolution, particularly in the case of the major 39

carbon- and oxygen-bearing species. We present ground-based high-resolution spectra from CRIRES/VLT at 3.2 microns of several transiting and non-transiting hot Jupiter atmospheres (51 Peg b, Tau Boo b, and HD 209458 b), in which we have searched for the radial velocity signature of water, methane and carbon dioxide molecules in the planetary atmospheres. We compare the results of our search with the detections of CO already reported in these hot Jupiter atmospheres, and discuss their temperature-pressure profiles and relative abundance ratios. Preliminary results indicate a significant abundance of water in 51 Peg b, consistent with tentative reports of water at 2.3 microns. Observation of Magnesium : A new Probe of Exoplanets' Thermospheres and Exopheres! Vincent Bourrier — Institut d'Astrophysique de Paris Transit observations of HD209458b in the UV revealed signatures of neutral magnesium escaping the planet upper atmosphere. The absorption detected in the MgI line arises from the transition region between the thermosphere and the exosphere, and provides unprecedented information on the physical conditions at the altitude where atmospheric escape takes place. These observations have been interpreted using a 3D particle model coupled with an analytical modeling of the atmosphere below the exobase. Thus we estimated the planetary wind velocity and the exobase altitude, and also obtained an new estimate of the atmospheric escape rate. More generally, we show that magnesium absorption lines provide a powerful tool to study the upper part of exoplanets' atmospheres. We identified a dozen of exoplanets with host stars bright enough for their atmosphere to be observed using the magnesium lines. Probing the atmospheres of non-transiting exoplanets: CO and H2O absorbtion in HD179949b! Matteo Brogi! — Leiden Observatory In recent years, ground-based high-resolution spectroscopy has become a powerful method for studying exoplanet atmospheres. It is capable to robustly identify molecular species via line matching, and to detect the radial velocity of the planet itself. Moreover, by targeting the planet thermal emission directly, it does not require the planet to transit. Thanks to this method, the mass and orbital inclination of non-transiting planets can be determined and their atmospheric composition studied. I will present our latest K-band observations of HD179949b with CRIRES at R=100,000. We detect an absorption signal from water vapour and carbon monoxide at SNR=6.5, meaning that the portion of the planet’s atmosphere probed by these observations does not have an inversion layer. The derived mass and orbital inclination for the planet are (0.98+/-0.04) Jupiter masses and (68+/-4) degrees respectively. Except for young, self-luminous directly-imaged planets, only high-resolution spectroscopy currently allows the atmospheric characterization of non transiting planets. With the next generation of ELTs and this technique, a complete census of this class of bodies will be possible, revealing for the first time their properties and actual mass distribution.

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Spectroscopic observations of the hot-Jupiter HD 189733b with HST WFC3 Nicolas Crouzet — Space Telescope Science Institute Spectroscopic observations of exoplanets are crucial to infer the composition and properties of their atmosphere. In particular, identifying molecular features and measuring their amplitude constrain the presence of and the effect of clouds, which are thought to play a major role in the atmosphere of hot-Jupiters. After a controversy on the reliability of NICMOS results, the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope now delivers hot-Jupiter spectra with much higher fidelity than HST NICMOS had in the past. We observed the well studied hot-Jupiter HD 189733b with WFC3 in the bandpass 1.1 to 1.7 microns using the newly implemented spatial scanning mode, which largely increases the number of collected photons compared to the staring mode. Also, the spatially-scanned WFC3 data produce satisfactory results with a very straight-forward analysis, a welcome change from the old technique of staring-mode observations, especially those obtained with HST NICMOS (Crouzet et al. 2012). We will discuss the amplitude of absorption seen in the transmission spectrum and the inferred atmospheric composition for HD 189733b, and compare them with recent results by Deming et al. (2013) for the exoplanets HD 209458b and XO-1b using similar WFC3 data. Our data reinforces the idea that molecular features of hot Jupiters may be attenuated by the presence of clouds or haze. We derive the planetary emission spectrum using the same technique with observations made at secondary eclipse. A Closer Look at Correlated-Noise Measuring Techniques for Exoplanet Light Curves Patricio Cubillos — University of Central Florida Among the many exoplanet light-curve fits analyzed to date, it is not unusual to detect some degree of time correlation in the residuals (also known as correlated or red noise). An incorrect assessment of correlated noise can lead to under- or overestimating the uncertainties on the planet's physical parameters, giving more or less significance to the results than they should have. While the sources of correlated noise are not always known (e.g., from an inaccurate systematics treatment or some unaccounted astrophysical effect), there are methods that aim to assess the degree of correlated noise, like the RMSvs.-bin size plot, prayer beads, and wavelet-based likelihood fitting. Yet, there are no indepth statistical studies in the literature for some of the techniques currently used. We subjected these correlated-noise assessment techniques to basic tests on synthetic data sets to characterize their features and limitations. Initial results indicate, for example, that sometimes the RMS-vs.-bin size plot has large artifacts when the bin size is similar to the observation duration. Further, prayer beads rarely indicate the right level of correction for correlated noise. We have applied these techniques to several Spitzer secondary-eclipse hot-Jupiter light curves and discuss their implications. New possibilities for exoplanet observations at high spectral resolution Remco de Kok — SRON In the last few years there have been several detections of molecules in hot-Jupiter atmospheres using observations at very high spectral resolution (R=100,000), most notably using CRIRES on the VLT. These observations have the great advantage that they allow unambiguous detection of specific molecules. On the other hand, determining 41

abundances of molecules in the atmosphere has not yet been possible using only highresolution observation due to degeneracies. We will discuss what other high-resolution measurements can be performed with current instruments to obtain a better understanding of the chemistry and dynamics of hot-Jupiter atmospheres. We will present results from our sensitivity analysis of simulated CRIRES observations, showing at what wavelengths particular molecules are best detected. We will also discuss whether molecules can be detected from high-resolution thermal radiation from the night-side. We find that for some planets the night-side might even yield a larger signal than the day-side. 2D mapping of the eccentric exoplanet HAT-P-2b! Julien!de Wit — Massachusetts Institute of Technology The class of close-in gas giant planets known as hot Jupiters provides an exceptional insight into atmospheric circulation, as these planets are expected to be both highly irradiated and in either synchronous or pseudo-synchronous orbits depending on their orbital eccentricity. We can probe atmospheric circulation through phase curve measurements, which tell us about their brightness as a function of longitude. Recently, a new observational tool, “eclipse mapping”, has been developed enabling the creation of maps that are resolved in both longitude and latitude, unlike phase curves. To date, only one planet (HD 189733b) has been successfully mapped using this technique. Here, we present the first two-dimensional maps of the eccentric exoplanet HAT-P-2b in the Spitzer 4.5 micron bandpass. This map is derived from fourteen new secondary eclipses observed in the 4.5 micron band. The high eccentricity of HAT-P-2b leads to fundamental differences between its atmospheric circulation and that of HD189733b. A high eccentricity prevents tidal locking and implies time-variable stellar heating, hence time-variable forcing. HAT-P-2b is eclipsed post-periastron, hence we use eclipse mapping to gain insights into how its atmosphere responds to transient heating. In particular, HAT-P- 2b’s map will yield constraints on its radiative and advective time-scales and probe the spatial extent of its dayside thermal inversion. We will discuss the implication of our findings in the context of atmospheric circulation models that can be applied to a wide range of planets. Mapping Clouds in Exoplanet Atmospheres Brice-Olivier Demory — Massachusetts Institute of Technology Clouds and hazes are ubiquitous in the solar system's giant planet and brown-dwarf atmospheres. It has been long suggested that clouds would also play a strong role in shaping the spectra of exoplanets in general and hot Jupiters in particular. Recently, clouds have been reported in the atmosphere of HD189733b. We will present the first results of a program aiming at detecting and characterizing clouds in hot-Jupiter atmospheres. We use joint space-based visible+IR occultation and phase-curve photometry to reconstruct low-resolution maps of thick clouds. We will discuss the possible formation scenarios for these clouds and explore the degeneracies involved in the retrieval of the particles properties (coverage, size distribution, vertical extent, composition, shape, etc.). We will finally discuss how near-to-come space- and ground-based facilities will contribute to the detailed characterization of these clouds.

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Characterising Exoplanets Using Kepler Phase-Curves! Lisa Esteves — University of Toronto! Although the Kepler mission is mainly aimed at searching for exoplanet transits, its highprecision photometry and long-term monitoring of the same field, makes it ideal to use for phase-curve measurements. Recently, using almost four years of Kepler data, we have been able to measure the phase-curve of eight Kepler objects. For five of these we present the very first phase-curve measurements, while for the other three objects we present greatly refined parameters. In addition we demonstrate how phase-curves measurements can be used as a very powerful tool for ruling out false positives within the Kepler planet candidate population. Measuring the reflection signal of HD189733b! Tom Evans — Oxford University! The multi-wavelength reflection signal of an exoplanet provides a valuable insight into the composition and structure of its atmosphere. In this talk, I will describe our measurement of a secondary eclipse of HD189733b across the 290-570nm wavelength range, made using HST/STIS. We found that the albedo of the planet decreases towards longer wavelengths in this range from approximately Ag=0.4 to Ag2000 K). We utilize secondary eclipse photometry at 3.6 and 4.5 µm taken with the IRAC camera aboard the Spitzer Space Telescope during the warm Spitzer mission and in the H and Ks bands with the WIRC camera at the Palomar 200-inch Hale Telescope. We discuss how the installation of a new diffusing filter in the WIRC filter wheel mitigates many of the systematic problems encountered during ground-based observations. With multiwavelength photometry and spectroscopy for a large sample of hot Jupiters, we can search for trends in atmospheric characteristics, including elemental abundances, C/O 47

ratios, and temperature profiles, that might be important clues to their formation and evolution. Models of exoplanet evaporation James! Owen — Canadian Institute for Theoretical Astrophysics Given the numerous exoplanets discovered at close separations to their parents stars, where the stellar UV & X-ray radiation fields can heat the upper layers of the planets atmosphere to 104K, evaporation is bound to occur. I will discuss evaporation in the hydrodynamic limit which can be driven by either the EUV or X-ray radiation, and the associated mass-loss rates. I will argue that evaporation of close-in exoplanets does not occur in `energy-limited' sense where PdV work dominates the energy loss, but that radiative cooling and recombinations are dominant energy sinks. Finally, I will present the results of multi-dimensional calculations and discuss the role planetary and stellar magnetic fields play in exoplanet evaporation, along with the long term impact of evaporation on exoplanets. Transit Transmission spectroscopy with GTC: First results Enric Palle — Instituto de Astrofisica de Canarias Our group is presently conducting an observational campaign, using the 10-meter Gran Telescopio Canarias (GTC), to obtain long-slit spectra in the optical range of several planetary host stars (and a reference star) during a transit event. The GTC instrument OSIRIS consists of two CCD detectors with a field of view of 7.8 X 7.8 arcmin. We used OSIRIS in its long-slit spectroscopic mode, selecting the grism R=1000 which covers the spectral range of 520-1040 nm, and a custom-built slit of 12 arcsec of width. A Markov Chain Monte Carlo (MCMC) Bayesian approach is used for the transit fitting, and the level of red noise in the light curves is estimated using the method of Winn et al. (2008). Here, we will present refined planet parameters, planet color signatures, and the transmission spectrum of a set of know transiting exoplanets, namely: WASP-43b, HAT-P-12b, WASP-48b, and KIC 12557548b. With our instrumental setup, GTC has been able to reach precision down to 250 ppm (WASP-48b, V=11.06 mag) for each color light curve 15 nm wide. We will also discuss the capabilities and advantages of GTC as tool for the follow up of faint Kepler targets, such as KIC 12557548b. The light curves obtained for this object with low resolution gratings allow us to reach 300 ppm in a 4-min sampled curve, thus revealing the detailed shape, small scale structures, and color information of individual transits of KIC12557548b. Characterisation of exoplanet atmospheres with KMOS Hannu Parviainen — University of Oxford We present our preliminary results and experiences with the KMOS (K-Band Multi-Object Spectrometer) instrument in the characterisation of exoplanet atmospheres using transit transmission spectroscopy, and detail our approach to the data reduction and analysis. Our experiences are mainly based on transits observed during the instrument's commissioning phase, and the investigation of the KMOS instrument's applicability to transit spectroscopy was an important secondary goal along with the science driver.

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Transit transmission spectroscopy offers a direct way to study the atmospheric properties of transiting exoplanets. However, the variations in the transit depth are small, of order 10-4, and disentangling the minute changes in the transit signal from the systematic noise signals is all but trivial. KMOS is a NIR multi-object spectrometer capable of observing spatially resolved spectra of 24 2.8x2.8 arcsecond freely positionable fields simultaneously. Each field is implemented using an integral field unit (IFU) with a 14x14 pixel spatial resolution. The ability to observe simultaneous spectra from a number of separate fields allows for high flexibility in the selection of comparison stars for relative spectroscopy, facilitating the reduction of common systematics. However, the use of IFUs with small spatial footprints creates also new challenges that need to be overcome before the instrument's full potential can be used. Direct evidence of the inversion layer in HD 209458 b from high-dispersion spectroscopy? Henriette Schwarz — Leiden University We present preliminary results from high-resolution thermal emission spectra of the hot Jupiter HD 209458 b. This bright transiting planet is interesting because it is a good candidate for a hot Jupiter with an inversion layer in its atmosphere. Snellen et al. (2010) observed HD 209458 b during a transit with high-resolution spectra at wavelengths around 2.3 micron, and they detected molecular absorption from carbon-monoxide. The new dataset again uses the CRIRES spectrograph at VLT. This time we are looking at the thermal emission from the hot day-side of the planet at phases close to the secondary eclipse. We see no evidence for CO absorption in the thermal spectra, but an interesting hint of CO emission — the tell-tale sign of a thermal inversion layer high up in the atmosphere of this planet. Atmospheric characterization of the hot Jupiter Kepler-13b Avi Shporer — Caltech/JPL Kepler-13b (= KOI-13.01) is a unique transiting hot Jupiter. It is one of very few known short-period (1.76 day) planets orbiting a bright (V~10 mag) A-type star. Therefore, it is among the hottest and brightest planets currently known, motivating the study of its atmosphere. The availability of Kepler data allows us to measure the planet's occultation (secondary eclipse) and phase curve, in the optical, with very high precision, which we combine with occultations observed by the Warm Spitzer Mission at 3.6 micron and 4.5 micron, and a ground-based occultation observation by the Wide-field Infra-Red Camera (WIRC), mounted on the Palomar 200 inch telescope, at the Ks band (~2.1 micron). Since the host star is the primary component of a visual binary system with ~1 arcsec separation, the two similar stars are fully blended in all our photometry. To correct the observed occultation depths for this dilution we modeled the stellar spectra, from the optical to the infrared, based on Keck/HIRES spectra that resolved the two stars. Our preliminary results indicate that the planetary atmosphere has a relatively high geometric albedo (Ag ~0.3) and a highly efficient heat distribution from the day side to the night side (epsilon ~0.9). This represents a deviation from previous studies in which the most highly irradiated hot Jupiters were found to have inefficient recirculation of energy from the day to the night sides. We also present revised atmospheric parameters for the planet-hosting star in this 49

triple stellar system, and a revised planetary mass estimate based on the beaming effect and the tidal ellipsoidal distortion observed in the Kepler phase curve. Revealing Distant Worlds with Ground-Based Spectroscopy Kevin Stevenson — University of Chicago Uncovering the fundamental properties of exoplanetary atmospheres requires highprecision spectroscopy over a broad range of wavelengths. We are poised to make significant advances in our understanding of their composition and chemistry using currently-available, visible and near-infrared multi-object spectrographs attached to some of the largest telescopes in the world. With facilities such as Gemini, Keck, and Magellan, we are conducting an intensive survey of a representative sample of exoplanets to measure their transmission and dayside emission spectra. We will present high-quality spectra for several recently-observed exoplanets and discuss how these data constrain the molecular abundances, thermal profiles, and relevant chemistries of these planetary atmospheres. Updated Spitzer Secondary Eclipse Spectroscopy of HD189733b Kamen Todorov — ETH Zürich We analyze Spitzer Space Telescope time-series spectroscopy observations of HD 189733b during 18 secondary eclipses at wavelengths between 5 and 14 microns. These measurements comprise the most extensive emission spectrum of any exoplanet to date. While some of these data sets have been analyzed previously by Grillmair et al. (2008), we examine eight of them for the first time. We remove the systematic effects from the spectral light curves using the most advanced techniques available, and measure the secondary eclipse depths as a function of wavelength. We use a modified version of a radiative transfer code by Richardson et al. (2003) to calculate three emergent spectrum models and compare our observational results with them, and with the best fit model (Burrows et al. 2008) adopted by Grillmair et al. in their earlier investigation. We can confidently exclude isothermal and gray atmospheres and confirm the water feature detected by Grillmair et al.

Phase curves of close-in Kepler planets Vincent Van Eylen — Aarhus University! The Kepler satellite has provided a wealth of new data on transiting exoplanets. Its unprecedented precision allows for more than just analyzing the transit: for hot planets in an orbit of only a few days, the parts-per-million precision allows for the detection of planetary light throughout the full phase, as well as its absence during the secondary eclipse. For those tidally locked planets, the increase in received flux as we view more and more of the planet's day side allows us to make statements on the planetary reflection (albedo) and temperature. Measuring the depth of the occultation leads to estimates on the temperature of the (cold?) planetary nightside. I present preliminary results on a comparative study of the sample of close in transiting exoplanets which were observed by Kepler.

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Water in the atmosphere of hot-Jupiter exoplanets Hannah Ruth! Wakeford — University of Exeter Using the Hubble Space Telescope’s WFC3 camera with an infrared low resolution grism, we observed a number of hot Jupiters from 1.1-1.7 µm, probing primarily the H2O absorption band at 1.4 µm. H2O is a key molecule for constraining hot-Jupiter atmospheres with the atmospheric C/O ratio playing a pivotal role in the relative H2O abundance. We present a variance in these hot Jupiter atmospheres with a strong H2O detection in the upper atmosphere of HAT-P-1b and new results from WASP-31b. The computed transmission spectra show a startling diversity in the observed abundance of H2O in the atmosphere of close-in giant planets allowing us to explore the nature of their relative environments. The 4.5 micron phase curve of HD 209458b! Robert Zellem — Lunar and Planetary Laboratory - University of Arizona! The hot Jupiter HD 209458b is one of the most favorable targets for full-orbit phase curve observations, as it is one of the brightest systems (V-mag = 7.65, K-mag = 6.308), has a large planet-to-star contrast, and offers a high signal-to-noise ratio and the ability to make high-precision measurements. This planet also serves as the archetype for a class of planets that have dayside temperature inversions; the differences between this class of planets and those lacking inversions (including HD 189733b) are currently not wellunderstood. Here we present the first full-orbit phase curve of HD 209458b observed with the Spitzer/IRAC 4.5 micron photometric band. Our data, which includes one primary transit and two secondary eclipses, was reduced with a pixel-mapping method to get within 1.145 times the photon noise limit. We measure the brightness temperature of the observed phase curve. The results are modeled with radiative transfer models along with other primary transit and secondary eclipse data to determine the pressure level of the emissions. We then compare these results to predictions from global circulation models, including those where magnetic effects and thermal inversions are present in order to determine the effect that HD 209458b\s dayside temperature inversion has on its atmospheric circulation and chemistry.

HOT JUPITERS: MODELS Effects of clouds on reflection properties of hot Jupiters! Nadine Afram — Kiepenheuer Institut für Sonnenphysik, Freiburg The presence of clouds in exoplanetary atmospheres may dramatically change their reflectivity properties. This can be detected during secondary eclipses and with the help of polarimetric techniques, independently of planet transits. Here, we model polarimetric phase curves and secondary eclipses for some very hot Jupiters with orbital periods shorter than 3 days (e.g., WASP-19b, HD189733b) using model atmospheres with and without clouds. We empirically adjust pressure-temperature profiles and the cloud composition and height and investigate how polarization and eclipse curves depend on atmosphere parameters. In particular, we consider such molecules and condensates as , 51

OH, H2, CO, CO2, CH4, NH3, MgO, MgSiO3, Mg2SiO4, Al2O3, etc. We compare our results with

available polarimetric and photometric measurements for hot Jupiters. Testing radiative transfer schemes for use in global circulation models of hot Jupiters! David Skålid!Amundsen — University of Exeter! Several studies which have used adapted Global Circulation Models (GCMs) to interpret observations of hot Jupiters have now been published. Almost all of these studies involve simplified dynamical (e.g shallow water or primitive equations) and radiative transfer schemes (temperature forcing, grey or band-averaged absorption coefficients). We are adapting the UK Met Office GCM, the Unified Model, which solves the full 3D compressible Euler equations and includes a frequency dependent radiative transfer scheme (invoking the two-stream approximation and correlated-k method) for the study of hot Jupiters. We will discuss the adaptation of the radiative transfer scheme and the tests we have performed to verify its accuracy. By comparing to more accurate discrete-ordinate line-byline calculations we will demonstrate that this scheme yields fairly accurate fluxes and heating rates overall. In some cases, however, there are significant deviations, and we find the use of band-averaged absorption coefficients to be very inaccurate. Lastly, I will present some of the first results we have obtained after recoupling the dynamical core and radiative transfer schemes. An Open Source Python Thermochemical Equilibrium Abundances Code! Jasmina Blecic — University of Central Florida We present a Thermochemical Equilibrium Abundances code (TEA) that calculates the equilibrium abundances of the molecular species present at a given temperature and pressure in a planetary atmosphere. There are two approaches to calculating thermochemical equilibrium: by using equilibrium constants and reaction rates or by minimizing the free energy of the system. Although chemical equilibrium can be calculated almost trivially for several reactions present in the system, as the number of reactions increases, the number of equilibrium-constant relations becomes difficult to solve simultaneously. An advantage of the free-energy-minimization method is that each species present in the system can be treated independently, without specifying complicated sets of reactions. Therefore, just a limited set of equations needs to be solved. TEA is based on the Gibbs-free-energy minimization calculation, originally developed by White et al. (1958) and Eriksson (1971). The code is written entirely in Python and is available to the scientific community under an open-source license. VSTAR Models of a Hot Jupiter Kimberly Bott -- University of New South Wales Past analysis of HD 189733b's atmosphere has been a cause for some debate, with conflicting findings regarding polarized light, carbon dioxide and sodium abundances and the presence of a high altitude haze. I will present our model of HD 189733b's atmosphere using VSTAR (Versatile Software for Transfer of Atmospheric Radiation), a robust, line-byline, multiple scattering radiative transfer solution in a modular program, utilitizing its own chemical equilibrium model. Since the effective temperature of the planet is expected to be approximately 1100K, newly available high-temperature spectral line lists were used. The 52

planet’s dayside, terminator and reflected polarized light are modeled and compared to available data. Circumplanetary Jet Formation, Characteristics, and Observational Diagnostics Ian Dobbs-Dixon — University of Washington! Ubiquitous among multidimensional simulations of highly irradiated gas-giant planets is the development of circumplanetary jets in the equatorial region of the planet. These jets, many of which become supersonic, are the dominant dynamical feature, helping to shape all observable features and perhaps influencing the thermal evolution of the entire planet. However, observations of irradiated gas-giants suggest that not all planets form such jets. Despite their importance for interpreting observations, the precise physical mechanism for forming and sustaining jets remains an area of active research. We lay out a linear theory for the formation of these jets and compare our predicted behavior to results from multidimensional radiative-hydrodynamical simulations. We then further discuss a novel observational technique for detecting these jets during a single eclipse. A faster method of detecting a jet will allow for a much broader survey of systems, hopefully shedding light on the physical parameters of the system that help or hinder jet formation. Escape of Hydrogen from HD209458b! Justin!Erwin — University of Arizona! Recent modeling of the atmosphere of HD209458b has been used to interpret the Lymanline and other observations during transits. Koskinen et al. (2010) used a hydrostatic density profile in the thermosphere combined with the Voigt profile to estimate the Lymanalpha transit depths for an array of model parameters. A detailed photochemical-dynamical model of the thermosphere was developed by Koskinen et al. (2013a) and used to again estimate model parameters to fit not only the Lyman-alpha transits, but also the transits in the O I, C II and Si III lines (Koskinen et al., 2013b). Recently, Bourrier and Lecavelier (2013) modeled the escape of hydrogen from the extended atmospheres of HD209458b and HD189733b and used the results to interpret Lyman-alpha observations. They included acceleration of hydrogen by radiation pressure and stellar wind protons to simulate the high velocity tails of the velocity distribution, arguing that the observations are explained by high velocity gas in the system while Voigt broadening is negligible. In this work we connect a free molecular flow (FMF) model similar to Bourrier and Lecavelier (2013) to the results of Koskinen et al. (2013b) and properly include absorption by the extended thermosphere in the transit model. In this manner, we can interpret the necessity of the various physical processes in matching the observed line profiles. Furthermore, the transit depths of this model can be used to re-evaluate the atmospheric model parameters to determine if they need to be adjusted due to the existence of the extended hydrogen tail. Thor: A GPU code for simulating exoplanetry atmospheres Simon!Grimm — University of Zürich We present an implementation of a three-dimensional general circulation model (GSM), designed for simulating exoplanetary atmospheres, running fully parallel on Graphics Processing Units (GPU’s). The Code is developed for the Exoclimes Simulation Platform (ESP) and will be available as open source software. Thor solves the three dimensional 53

non hydrostatic Euler equations on a modified Yin-Yang grid, which consists of an equatorial belt and two polar caps, which are patched together using a fully conservative zonal interface algorithm, described by Wang (1995). The individual grids are solved with a horizontal explicit and vertical implicit (HEVI) finite difference scheme, where the vertical solution can be computed analytically. In this poster we present the implemented scheme and show as well results of the first tests, including a quantification of the conservation of energy, mass and momentum. Compared to other available CPU codes, Thor shows a speed-up of around one magnitude. Thor is written in Cuda C and runs on all Nvidia GPU's. The Exoclimes Simulation Platform! Kevin! Heng! — Center for Space and Habitability, University of Bern ! The state of the art in performing 3D simulations of exoplanetary atmospheres centers around adapting GCMs (general circulation models), originally designed for the study of Earth. These Earth-centric tools suffer from fundamental shortcomings, including Earthcentric assumptions, the inability to model shocks, the exclusion of magnetic fields and the treatment of radiative transfer as if the atmosphere is static. We offer an alternative perspective: the design and development of a set of publicly available, theoretical and simulational tools for the general exoplanet community, partly to combat the growing "black box" culture in our field. I give a brief and broad review of the Exoclimes Simulation Platform (ESP), focusing on the GCMs and radiative transfer tools that are currently in development. I will also explain our decision to build the ESP entirely on GPUs, which gives our open-source tools a speed-up of at least an order of magnitude (two orders of magnitude for radiative transfer). I will describe how we plan to involve the community via a web portal (www.exoclime.org), which includes a Facebook page for soliciting feedback. VIPER: Toward a universal model for planetary climate Nicolas Iro — University of Hamburg With the discovery of an increasing number of planets outside our Solar System, we are becoming familiar with physical conditions and atmospheric compositions that span a much wider range that what covered by the planets of our solar system. Non-exhaustive examples are equilibrium temperatures ranging from 50K (Neptune) to over 3000K (WASP-12b, WASP18b); orbital eccentricity, ranging from 0-0.1 for solar system planets (except Mercury) and circularized close-in hot Jupiters to e = 0.93 (HD80606b). Other parameters relevant for atmospheric dynamical features are also quite diverse: the Rhines length and Rossby length are, e.g., much smaller than the planet radii for Solar-System planets, while they are comparable to the planetary radii for hot Jupiters and Neptunes, meaning that in the latter case typical circulation features are global. It seems timely and urgent to try to frame in a common framework our understanding of such a large variety of atmospheric conditions. We will present VIPER, the Versatile Interactive PlanetSimulator for Extrasolar Research. This project, under development, aims at developing the Planet Simulator, an already flexible climate model to a new level of modularity. In the next phase of the implementation, we will remove all parameterization pertaining to Earth, allowing for instance to study any planetary rotation rate and add a simple yet precise radiative scheme based on the k-distribution coefficients. This will allow us to model the climate on a variety of planetary conditions from early Mars to Super-Earths.

54

Modelling of the Emission Spectrum of WASP-19b Lucyna Kedziora-Chudczer — University of New South Wales The VSTAR radiative transfer code was used to model the emission spectrum of the one of the most irradiated hot-Jupiters, WASP-19b. We examined models with different pressure-temperature profiles and C/O abundances ratios. We find that models with carbon enrichment above solar match the available data best. We also included upperatmosphere haze of varied particle sizes and find that particles 3 micron). However, the difficulty of working in the thermal infrared from the ground has precluded the detailed studies of exoplanets at these longer wavelengths. Using the low-emissivity adaptive optics systems at the LBT and Magellan, we present 6 new photometric points on the HR 8799 planets and 1 new photometric point on 2M1207 b. These data probe the 3-4 micron region where previous studies have found a 1-2 magnitude discrepancy between their atmospheres and field brown dwarfs. For the HR 8799 planets, we find a shallow 3-4 micron slope with only a hint of possible absorption in the methane 3.3 micron fundamental absorption band (possibly indicating the presence of patchy clouds). For 2M1207 b we find a similar if more extreme behavior, with no sign of methane absorption. The study has implications for understanding the broad properties of extrasolar giant planets, and suggests that future mid-infrared direct-imaging searches (particularly JWST) may need to reconsider their search strategy. A large near-IR photometric monitoring survey of 69 ultracool L &T brown dwarfs Paul Anthony !Wilson — University of Exeter As the brown dwarf atmosphere cools through the L-T spectral sequence a rapid shift from the red to the blue colours are observed across the L-T type transition. This shift in colour happens across a narrow effective temperature range, which is hard for 1-D atmosphere models to currently reproduce. Patchy clouds might be the explanation of the rapid change in colour observed over a narrow temperature range. The consequence of patchy clouds would be variations in the observed flux due to the rotation and evolution of the clouds. I will present the results from our large near-IR photometric monitoring campaign which covers 69 ultracool L & T type brown dwarfs. In particular I will discuss the frequency and amplitude of variability across the different spectral types highlighting that our survey finds new large amplitude variables across the L - T spectral range showing no preference for the transition. I will also talk about observing variability at the much cooler T-Y transition.

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