objects), as well as a select sample of over 500 M dwarfs. In this poster, we ...
reason is that the L & T dwarf database is intended to contain all known objects ...
DwarfArchives.org: A Compendium of M, L, and T Dwarf Data Christopher R. Gelino (Spitzer Science Center/Caltech), J. Davy Kirkpatrick (IPAC) & Adam J. Burgasser (MIT) DwarfArchives.org is an online archive containing astrometric, photometric, and spectroscopic information for all known L and T dwarfs (over 650 objects), as well as a select sample of over 500 M dwarfs. In this poster, we describe the specific data available in the archive and the interface for searching through it. We discuss scientific uses for the archive and plans for future updates. Archive Features and Content The data presented in DwarfArchives.org are divided into two separate databases. The L and T Dwarf database contains astrometric, photometric, and spectroscopic information for all spectroscopically determined L and T dwarfs. The M dwarf database contains a select sample of >500 dwarf and giant stars with uniformly determined spectral types between late K and late M. The front page of DwarfArchives.org (shown at right) has links to several useful, pre-sorted lists (eg. all L and T dwarfs with measured parallaxes). In addition, search forms are available to allow users the ability to create customized lists based on their own search criteria. The front page also includes links to educational material about L and T dwarfs. This material includes information about the classification of L dwarf spectra, artwork depicting the relative sizes of stars, brown dwarfs, and planets, and near-IR images of some L and T dwarfs. In addition, the user can find a list of recent updates, an FAQ, and links to other websites that might be of interest to the user.
Key Features • the ONLY online database containing photometry and astrometry for ALL known L and T dwarfs • fully searchable database • fully referenced data with links to ADS abstracts • spectroscopic standards for late-K, M, L, & T dwarfs
Current Contents •Over 1200 objects •146 T dwarfs •526 L dwarfs •507 M dwarfs/giants •27 K dwarfs/giants •2 Dwarf carbons •81 objects with parallaxes •682 optical spectra (late K-late M)
Available Data L and T Dwarfs • J, H, & Ks photometry for nearly all objects (mostly 2MASS photometry) • optical and near-IR spectral types • trigonometric parallaxes and proper motions • links to 2MASS, DSS, and SDSS finder charts • important notes (e.g. binarity) • references for discovery papers, parallaxes, proper motions, and spectral types M Dwarfs • 2MASS J, H, & Ks photometry for nearly all objects • uniformly determined optical spectral types • 2MASS, DSS, and SDSS finder charts • optical spectra • spectral type and spectrum references
Search Form The L & T dwarf data are separate from the M dwarf data. The reason is that the L & T dwarf database is intended to contain all known objects with those spectral types, whereas the M dwarf database only contains a small selection of M dwarfs. The Search Engines for both databases have similar functionality, with the only difference related to the different fields within the respective databases. For example, currently only the M dwarf database contains spectra and searches are allowed on the spectra metadata.
The user can search for a specific name or a string within a name It is possible to search around a single coordinate or upload a list of coordinates. This search uses the IRSA LookUp Service which can handle coordinates in a variety of formats as well as provide name resolution for common star names. The data can be sorted in ascending or descending order.
The result table can either be HTML or plain text (L/T searches only).
Values for the search criteria are inserted into these boxes. You must include the comparison operators (,=). RA and Dec can be inserted as sexigesimal or decimal values.
Online help is available for each of the fields by clicking on the parameter name.
The user can require that a measurement exists or does not exist by using these check boxes. This is useful for selecting only those objects for which a parallax is available, for example.
Checks in the Select column indicate the fields to be returned. This column is used to choose the field on which the data results are sorted.
These buttons are used to change the type of logic used when searching with a lower and an upper limit.
Results Table The results table for the L/T dwarfs and the M dwarfs are similar. Both provide Finder Charts, requested data, and hyperlinks to ADS Abstracts. M dwarf results with spectra contain an additional column with spectra metadata, a link to a quick-look preview of the spectra, and an ASCII table of the data.
Clicking on the 2MASS designation (M Dwarf tables) or the Discovery Name (L/T Dwarf tables) sends a request to IRSA’s Finder Chart service to generate multi-band images of the field. Each finder chart displays the 2MASS J, H, and Ks fields, DSS images, and SDSS images (where available).
Finder Chart
Uses and Future Plans
Preview
The preview link generates a quick-look plot of the spectral data. Included below the spectrum is the information present in the ASCII spectrum header. The header table includes links to references in which the spectrum was used. Many of our spectra are unpublished; we plan on presenting these spectra in a future paper.
Future Plans • incorporate optical and near-IR spectra (including previews) for L
Possible science uses of the archive • The position search feature combined with the multiwavelength finder charts makes it simple to search for possible L or T dwarf companions to more massive stars. For example: are there any L or T dwarfs within 30" of a Hipparcos star that share similar motions? • This archive is perfect for creating target lists for observing runs or for starting new observing projects (e.g. which objects need trigonometric parallaxes?) • The optical M dwarf spectra provide lists of spectral standards for researchers to observe during their spectroscopic programs. • The optical and near-IR spectral types combined with near-IR colors can be used to examine multiplicity, metallicity, and other physical attributes.
Clicking on a reference for a measurement (not shown here) brings up either the ADS abstract (for published articles) or the arXiv astro-ph abstract (for preprints). While we appreciate acknowledgements for the Archive use, users should cite original references in scientific writings.
Check boxes are used to select which ASCII spectra are to be downloaded. The user can also use the “Select All” and “Unselect All” buttons at the top of the table to quickly act on the entire table. The “Download Spectra” button creates a gzipped tar file of the selected data.
and T dwarfs • include additional photometry for L and T dwarfs: SDSS (r, i, z), UKIDSS (Y, J, H, K), MKO system (z, Y, J, H, K, Ks, L', M') , DENIS (I, J, K), Spitzer IRAC (3.6, 4.5, 5.8, 8.0 microns) • include additional M dwarf spectra from Keck/LRIS • continue to add newly discovered L and T dwarfs and new measurements for existing objects
This figure shows the all-sky distribution of objects in these databases. Asterisks are objects in the M dwarf Database, diamonds are L dwarfs, and triangles are T dwarfs.
The success of this archive depends immensely on support from the community. We appreciate all past, present, and future assistance that you may provide. Please do not hesitate to contact us with corrections, suggestions, and complaints. This work makes use of the 2MASS archive, the ADS abstract service, and several IRSA services. Our server was funded by a NASA Small Research Grant administered by the American Astronomical Society. We thank them for their generosity.
