PASJ: Publ. Astron. Soc. Japan , 1–??, c 2013. Astronomical Society of Japan.
Lightcurve Survey of V-type Asteroids in the Inner Asteroid Belt Sunao Hasegawa,1 Seidai Miyasaka,2 Hiroyuki Mito,3 Yuki Sarugaku,1 Tomohiko Ozawa,4 Daisuke Kuroda,5 Setsuko Nishihara,1,6 Akari Harada,6 Michitoshi Yoshida,7 Kenshi Yanagisawa,5 Yasuhiro Shimizu,5 Shogo Nagayama,8 Hiroyuki Toda,5 Kouji Okita,5 Nobuyuki Kawai,9 Machiko Mori,10 Tomohiko Sekiguchi,11 Masateru Ishiguro,12 Takumi Abe,1 and Masanao Abe1
arXiv:1311.4653v1 [astro-ph.EP] 19 Nov 2013
1
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 252-5210, Japan
[email protected] 2 Tokyo Metropolitan Government, 2-8-1 Nishishinjyuku, Shinjyuku, Tokyo 163-8001, Japan 3 Kiso Observatory, Institute of Astronomy, The University of Tokyo, 10762-30 Mitake, Kiso, Nagano 397-0101, Japan 4 Misato Observatory, 180 Matsugamine, Misato, Wakayama 640-1366, Japan 5 Okayama Astrophysical Observatory, National Astronomical Observatory, 3037-5 Honjo, Kamogata-cho, Asakuchi, Okayama 719-0232, Japan 6 Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan 7 Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan 8 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 9 Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551, Japan 10 Graduate School of Science, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo, Tokyo 112-8681, Japan 11 Asahikawa Campus, Hokkaido University of Education, 9 Hokumon, Asahikawa, Hokkaido 070-8621, Japan 12 Astronomy Program, Department of Physical and Astronomy, Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul 151-742, Korea (Received ; accepted )
Abstract We have observed the lightcurves of 13 V-type asteroids ((1933) Tinchen, (2011) Veteraniya, (2508) Alupka, (3657) Ermolova, (3900) Knezevic, (4005) Dyagilev, (4383) Suruga, (4434) Nikulin, (4796) Lewis, (6331) 1992 FZ1 , (8645) 1998 TN, (10285) Renemichelsen, and (10320) Reiland). Using these observations we determined the rotational rates of the asteroids, with the exception of Nikulin and Renemichelsen. The distribution of rotational rates of 59 V-type asteroids in the inner main belt, including 29 members of the Vesta family that are regarded as ejecta from the asteroid (4) Vesta, is inconsistent with the best-fit Maxwellian distribution. This inconsistency may be due to the effect of thermal radiation Yarkovsky– O’Keefe–Radzievskii–Paddack (YORP) torques, and implies that the collision event that formed V-type asteroids is sub-billion to several billion years in age. Key words: solar system — minor planets, asteroids
1.
Introduction
Rotational rate is one of the basic physical parameters of asteroids, along with albedo, size, shape, and spin vector. It is possible to determine the rotational rate of an asteroid from its lightcurve. The lightcurve of an asteroid can readily be obtained by relative photometric observations with telescopes of small diameter, although this takes considerable time. Multi-epoch lightcurve observations can be used to derive the shapes and spin vectors of asteroids (Magnusson et al. 1989; Kaasalainen et al. 2001). Combining multi-epoch lightcurve observations with mid-infrared or occultation data enables the albedo and size of asteroids to be determined (M¨ uller et ˘ al. 2007; Durech et al. 2011). The rotation rate of asteroids is a useful means to constrain asteroidal evolution. It is known that the rotation rate distribution of asteroids whose diameters are larger than ∼40 km is close to a Maxwellian distribution (Pravec
et al. 2002). Numerical simulations have shown that spin rates generated by the collisional history of asteroids generates a Maxwellian distribution (Salo 1987). This suggests that such asteroids are planetesimals of the main belt region and/or their remnants produced by collisional disruption. In contrast, the rotation rate distribution of asteroids smaller than ∼40 km in diameter does not follow a Maxwellian distribution. This suggests that the driving forces for the change in rotation rates results from catastrophic impact, as well as secondary collisions, reaccretion, and Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effects. The asteroid (4) Vesta is considered to be the smallest terrestrial planet as it is the only differentiated asteroid with an intact internal structure with a basaltic surface, an ultramafic mantle, and a metal core. The surface spectrum of Vesta has absorption bands in the visible and near-infrared wavelength regions that are similar in spectral shape, wavelength, and depth to the bands found in
2
S. Hasegawa et al.
spectra of howardite, eucrite, and diogenite (HED) meteorites (McCord et al. 1970; Larson & Fink 1975). A vast crater 460 km in diameter and 13 km deep with a central peak and raised rim is present at Vesta’s south pole, which is a triaxial ellipsoid with dimensions of 578, 580, and 458 km (Thomas et al. 1997). Zappal` a et al. (1990b) inferred that Vesta has an asteroid family and Moth´e-Diniz et al. (2005) reported that the Vesta family contains ca. 4500 members. Numerous asteroids with Vesta-like visible spectra are typically referred to as ‘V-type asteroids’. These asteroids have a near-Earth orbit (Cruikshank et al. 1991) in the inner main belt, which is influenced by a 3:1 mean motion resonance and the ν6 secure resonance of Jupiter (Binzel & Xu 1993). Approximately 3000 Vtype asteroids have been identified by spectroscopic and spectrophotometric methods (Cruikshank et al. 1991; Xu et al. 1995; Spahr et al. 1997; Binzel et al. 2001; Bus & Binzel 2002; Binzel et al. 2004a; Binzel et al. 2004b; Duffard et al. 2004; Lazzaro et al. 2004; Marchi et al. 2005; Alvarez-Candal et al. 2006; de Le´on et al. 2006; Duffard et al. 2006; Roig & Gil-Hutton 2006; Davies et al. 2007; Carvano et al. 2010; Solontoi et al. 2012; Sanchez et al., 2013). Gladman et al. (1997) used numerical simulations to propose that most impact objects to Earth belong to the Vesta family and Binzel et al. (2004b) noted that the most likely source of V-type near-Earth asteroids is the Vesta family, given the lack of V-type Mars crossers. Carruba et al. (2007) showed that V-type asteroids outside the Vesta family were scattered by close encounters with Vesta, and that they formerly belonged to the Vesta family. Roig et al. (2012) constrained the mechanisms of a large fraction of V-type asteroids that are observed to be outside the Vesta family. These studies all suggest that most V-type asteroids in the inner main belt are ejecta from Vesta, and that HED meteorites are sourced from Vesta and V-type asteroids through the 3:1 and ν6 resonances. The rotational rates of V-type asteroids are poorly constrained, due to the limited number of such asteroids that have currently been studied. As such, in order to better constrain the rotational rate distribution of asteroids sourced from Vesta, we have begun (since Fall 2003) lightcurve observations of V-type asteroids in the inner < main belt (semi major axis 2.1 < ∼ a ∼ 2.5) and determined rotational rates, along with amplitude variations (Hasegawa et al. 2004; Hasegawa et al. in press). Our study contributes to determination of an increased number of reliable rotation rates that allows statistically meaningful interpretations of this data for V-type asteroids to be carried out. Herein, we present lightcurve observations for a number of V-type asteroids. Subsequent sections of this paper describe the observations and data reduction procedures (Section 2), results of the lightcurve analyses (section 3), and implications of our results for the origin(s) of V-type asteroids (Section 4).
2.
[Vol. ,
Observations and data reduction procedures
Our observational survey of lightcurves for V-type asteroids was carried out using six different telescopes between Fall 2004 and Spring 2005. Fifty-nine lightcurves were recorded at the Kiso Observatory using two different telescopes in Nagano, Japan (MPC code 381), the Miyasaka Observatory in Yamanashi, Japan (MPC code 366), the Okayama Astrophysical Observatory in Okayama, Japan (MPC code 371), the Misato Observatory in Wakayama, Japan (no MPC code), and the UH88 telescope in Hawaii, USA (MPC code 568). Details of the nightly observational conditions are listed in Table 1. Thirty-three lightcurve observations from the 1.05 m Schmidt telescope at the Kiso Observatory were made using an SITe TK2048E CCD detector (2048 x 2048 pixels), giving an image scale of 1.5′′ /pixel located in the Schmidt focus. The field of view of the CCD was 51′ × 51′ . Integration times for the observations were 120 to 300 s. The full-width half maximum of star images at this site was typically 5–8′′ . Three lightcurves were recorded using the 0.30 m Dall– Kirkham telescope at the Kiso Observatory (K.3T). K.3T consisted of a MUTOH CV16II CCD camera with a Kodak KAF-1600 chip format, which captures 1536 × 1024 pixels with an image scale of 1.35′′ /pixel under 2 × 2 binning, giving a 17.3′ × 11.5′ sky field. The integration times for these observations were 300 s. Eighteen of the lightcurves were obtained using the 0.36 m Ritchey–Chr´etien telescope at the Miyasaka Observatory. The telescope was equipped with an SBIG STL-1001E CCD camera with Kodak KAF-1001E detector whose format is 1024 × 1024 pixels. This system produced image dimensions of 1.7′′ /pixel, yielding a field of view of 29.4′ × 29.4′ . The observational integration time was 300 s. The full-width half maximum of stellar images at this site was typically 5–8′′ . Two lightcurves were made with the 0.50 m Classical– Cassegrain telescope (MITSuME) at the Okayama Astrophysical Observatory (Yanagisawa et al. 2010). An Apogee U6 camera with a Kodak KAF-1001E detector yielded a format of 1024 × 1024 pixels with an image scale of 1.5′′ /pixel and a sky field of 25.6′ × 25.6′ . Integration times for these two lightcurves were 120 s. The full-width half maximum of stellar images at this site was typically 3–5′′ . Two lightcurve observations were carried out with the 1.05 m Cassegrain telescope at the Misato Observatory. The lightcurves were recorded with a SBIG ST-9E CCD camera and Kodak KAF-0261E detector (512 × 512 pixels; angular resolution of 1.0′′ /pixel); sky field of 9′ × 9′ ). Integration times for these observations were 30 to 180 s. The full-width half maximum of stellar images at this site was typically 3–5′′ . One lightcurve was recorded using the 2.24 m telescope at Mauna Kea (UH88), equipped with a wide-field imager 1
hhttp://ssd.jpl.nasa.gov/horizons.cgi#topi.
comprising eight 2048 × 4096 pixel CCDs. The projected area was 33′ × 33′ , which corresponds to an angular resolution of 0.45′′ /pixel. The integration times were 30 s. The full-width half maximum of stellar images at this site was ca. 1′′ . All observations were carried out through an R band filter. The dark images for correction were constructed from a median combination of 5–20 dark frames. Dome flat fielding images were obtained from the 1.05 m Schmidt, 0.36 m Miyasaka, 1.05 m Misato, and UH88 telescopes. Flat fielding images by K.3T and MITSuME were taken during the evening and/or morning twilight. Stacked flat fielding images for correction were created by a median combination of 10–20 flat fielding frames. Light image reduction involved dark subtraction and flat-field correction, and was performed by Image Reduction and Analysis Facility (IRAF) software. The asteroids and stellar stars for comparison were measured through a circular aperture with a diameter three times that of the full-width half maximum size used for the APPOT task of IRAF. All lightcurves were constructed using relative magnitudes. The fluxes of 5–20 stars in the same frame as each asteroid were measured for comparison. The flux difference between the asteroid and sum of the comparison stars were then computed. Variable stars were not used as comparison stars. Light travel time was corrected to obtain an accurate lightcurve epoch. A G parameter value for V-type asteroids is necessary for phase function correction, and we used values of 0.32 (G parameter value of Vesta) and 0.15 (G parameter value of typical asteroids). Zappal`a et al. (1990a) and Ohba et al. (2003) reported that the amplitude of asteroid lightcurves is affected by the phase angle. As such, a coefficient value (m = 0.02) equal to the median value for surface roughness of asteroids (Ohba et al. 2003) was adopted to correct lightcurve amplitude for the phase angle = 0◦ . Fourier analysis (FFT) and phase dispersion minimization methods (PDM) described by Stellingwerf (1978) were utilized for determination of the asteroidal rotational periods. Rotational periods were finally determined by considering the best result obtained by the two methods. 3. 3.1.
Results V-type asteroids
3.1.1. (1933) Tinchen The asteroid (1933) Tinchen is a V-type asteroid (Xu et al. 1995) that belongs to the Vesta family (Moth´eDiniz et al. 2005). Masiero et al. (2011) reported that the diameter of (1933) Tinchen is 6.45 km. Tinchen was observed during its apparition in March 2005 (Fig. 1), and a rotational period of 3.671 ± 0.002 h was obtained. On the Observatoire de Geneve website of Behrend (http://obswww.unige.ch/∼behrend/page cou.html), the rotational period of (1933) Tinchen was reported to be 3.67 h, which is in excellent agreement with our result. The quality code (U) scale as used for the Asteroid Lightcurve Database by Warner et al. (2009). The aster-
relative magnitude (!=0º) [mag]
Lightcurve Survey of V-type Asteroids
3
1933 Tinchen (P=3.671 hour)
-0.2
0
0.2
0.4 03/07-1.05m Schmidt 03/08-1.05m Schmidt 03/12-0.36m Miyasaka 03/13-0.36m Miyasaka
0.6 0
0.5
1
1.5
2
2.5
3
3.5
rotational period [hour]
Fig. 1. Composite rotational lightcurve of the asteroid (1933) Tinchen.
relative magnitude (!=0º) [mag]
No. ]
2011 Veteraniya (P=8.2096 hour)
-0.4 -0.2 0 0.2 0.4 0.6
11/12-1.05m Schmidt 01/08-0.36m Miyasaka 01/09-0.36m Miyasaka
0.8 0
1
2
3
4
5
6
7
8
rotational period [hour]
Fig. 2. Composite rotational lightcurve of the asteroid (2011) Veteraniya.
oid is valued as U = 3−. 3.1.2. (2011) Veteraniya The asteroid (2011) Veteraniya has a Vesta-like spectrum (Xu et al. 1995) and is a member of the Vesta family (Moth´e-Diniz et al. 2005). The diameter of the asteroid has been estimated to be 5.19 km (Masiero et al. 2011), but the period of this asteroid was not known prior to our study. Veteraniya was observed during its apparition in November 2004 and January 2005 (Fig. 2), and yielded a rotational period of 8.2096 ± 0.0003 h. The asteroid is estimated as U = 3−. 3.1.3. (2508) Alupka The asteroid (2508) Alupka is a Vestoid (Bus & Binzel 2002) and a member of the Vesta family (Moth´e-Diniz et al. 2005). The size of the asteroid is 5.17 km in diameter
-0.2
2508 Alupka (P=17.70 hour) 0
0.2
0.4
0.6
11/12-1.05m Schmidt 11/13-1.05m Schmidt 11/15-1.05m Schmidt
0
2
4
6
8
10
12
14
relative magnitude (!=0º) [mag]
S. Hasegawa et al. relative magnitude (!=0º) [mag]
4
[Vol. , -0.2
3657 Ermolova (P=2.582 hour) -0.1 0 0.1 0.2 0.3 0.4 5/05-1.05m Schmidt 5/09-1.05m Schmidt 5/14-1.05m Schmidt
0.5
16
0
rotational period [hour]
(Masiero et al. 2011). The period of this asteroid was not known prior to this study. Alupka was observed during its apparition in November 2004 (Fig. 3) and yielded a rotational period of 17.70 ± 0.05 h. The asteroid is evaluated with U = 2−. 3.1.4. (3657) Ermolova The asteroid (3657) Ermolova is a Vestoid (Xu et al. 1995) and part of the Vesta family (Moth´e-Diniz et al. 2005). Thermal observations of the asteroid have indicated it has an effective diameter of 5.79 km (Usui et al. 2011). Ermolova was observed during its apparition in May 2005 (Fig. 4), and a rotational period of 2.582 ± 0.004 h was determined for this asteroid. On the websites of Behrend and Pravec et al. (http://www.asu.cas.cz/∼ppravec/neo.htm) rotational periods of 2.6066 and 2.6071 h were reported for (3657) Ermolova, respectively. Even taking into account uncertainties, our rotational period result is slightly different to these web-published results. The asteroid is valued as U = 2−. 3.1.5. (3900) Knezevic The asteroid (3900) Knezevic is a V-type asteroid (Bus & Binzel 2002) of the Vesta family (Moth´e-Diniz et al. 2005). The asteroid is 4.96 km in diameter (Masiero et al. 2011). The period of this asteroid was not known prior to our study. Knezevic was observed during its apparition in January and February 2005 (Fig. 5) and gave a rotational period of 5.324 ± 0.001 h. The asteroid is rated as U = 3−. 3.1.6. (4005) Dyagilev The asteroid (4005) Dyagilev is a V-type asteroid (Xu et al. 1995), but is not a member of Vesta family (Moth´eDiniz et al. 2005). However, the asteroid is positioned in the inner main belt region. Masiero et al. (2011) estimated that the diameter of the asteroid (4005) Dyagilev
1
1.5
2
2.5
rotational period [hour]
Fig. 4. Composite rotational lightcurve of the asteroid (3657) Ermolova.
relative magnitude (!=0º) [mag]
Fig. 3. Composite rotational lightcurve of the asteroid (2508) Alupka.
0.5
-0.4
3900 Knezevic (P=5.324 hour)
-0.2 0 0.2 0.4 0.6 01/16-1.05m Schmidt 01/17-1.05m Schmidt 01/18-1.05m Schmidt 02/04-0.36m Miyasaka
0.8 1 0
1
2
3
4
5
rotational period [hour]
Fig. 5. Composite rotational lightcurve of the asteroid (3900) Knezevic.
is 8.36 km. The period of this asteroid was not known before this study. Dyagilev was observed during its apparition in March 2005 (Fig. 6) and yielded a rotational period of 6.400 ± 0.006 h. The asteroid is assessed at U = 3−. 3.1.7. (4383) Suruga The asteroid (4383) Suruga has a Vesta-like spectrum (Roig & Gil-Hutton 2006), but is not a member of the Vesta family (Moth´e-Diniz et al. 2005), although it is positioned in the inner main belt region. The diameter of this asteroid has been estimated to be 7.92 km (Masiero et al. 2011). The period of this asteroid was not known before this study. Suruga was observed during its apparition in December 2004 (Fig. 7) and a rotational period of 3.811 ± 0.003 h was obtained for this asteroid. The asteroid is estimated as U = 2−.
4005 Dyagilev (P=6.400 hour)
-0.1
0
0.1
0.2
0.3 03/07-1.05m Schmidt 03/08-1.05m Schmidt 03/13-0.36m Miyasaka
0.4 0
1
2
3
4
5
relative magnitude (!=0º) [mag]
Lightcurve Survey of V-type Asteroids
relative magnitude (!=0º) [mag]
No. ]
6
rotational period [hour]
4383 Suruga (P=3.811 hour) 0
0.05
0.1
12/17-1.05m Misato 12/20-2.24m UH88
0.5
1
1.5
2
2.5
3
4434 Nikulin
0.1
0
-0.1
-0.2 10/15-0.36m Miyasaka 10/16-0.36m Miyasaka 10/17-0.36m Miyasaka
-0.3 10
12
14
16
18
20
3.5
rotational period [hour]
Fig. 8. Composite rotational lightcurve of the asteroid (4434) Nikulin.
relative magnitude (!=0º) [mag]
relative magnitude (!=0º) [mag]
-0.05
0
0.2
obs time (corrected light time) [hour]
Fig. 6. Composite rotational lightcurve of the asteroid (4005) Dyagilev.
0.15
5
4796 Lewis (P = 3.5080 hr)
-0.2
0
0.2
0.4 9/15-1.05m Misato 10/1-0.36m Miyasaka 10/14-0.30m K.3T 10/15-0.30m K.3T
0.6 0
0.5
1
1.5
2
2.5
3
3.5
rotational period [hour]
Fig. 7. Composite rotational lightcurve of the asteroid (4383) Suruga.
Fig. 9. Composite rotational lightcurve of the asteroid (4796) Lewis.
3.1.8. (4434) Nikulin The asteroid (4434) Nikulin has a Vesta-like spectrum (Xu et al. 1995), but does not belong to the Vesta family (Moth´e-Diniz et al. 2005). However, this asteroid is positioned in the inner main belt region. The asteroid is 5.11 km in diameter (Masiero et al. 2011). The period of (4434) Nikulin was not known before this study. Nikulin was observed during its apparition in October 2004 (Fig. 8). Despite three nights of observations, the rotational period of (4434) Nikulin was not able to be determined due to its small amplitude.
(4796) Lewis has been estimated to be ∼ 5.2 km, using the assumption that its albedo is the same as the median value of other V-type asteroids (pv = 0.343; Mainzer et al. 2012). The period of this asteroid was not known before this study. Lewis was observed during its apparition in September and October 2004 (Fig. 9) and determined to have a rotational period of 3.5080 ± 0.0002 h. The asteroid is evaluated with U = 2+.
3.1.9. (4796) Lewis The asteroid (4796) Lewis is a V-type asteroid (Bus & Binzel 2002), but is not a member of the Vesta family (Moth´e-Diniz et al. 2005). However, the asteroid is positioned in the inner main belt region. The diameter of
3.1.10. (6331) 1992 FZ1 The asteroid (6331) 1992 FZ1 is a Vestoid (Duffard et al. 2004) that belongs to the Vesta family (Moth´e-Diniz et al. 2005). The asteroid has an effective diameter of 5.32 km (Masiero et al. 2011). The period of this asteroid was not known before this study. 1992 FZ1 was observed during its apparition in October and November 2004 (Fig. 10) and yielded a rotational period of 9.3333 ± 0.0005 h.
-0.2
relative magnitude (!=0º) [mag]
S. Hasegawa et al. relative magnitude (!=0º) [mag]
6
6331 1992 FZ1 (P=9.3333 hour)
0 0.2 0.4 0.6 10/15-0.30m K.3T 10/16-0.50m Okayama 10/17-0.50m Okayama 11/6-0.36m Miyasaka
0.8 0
2
4
6
8
relative magnitude (!=0º) [mag]
-0.2
8645 1988 TN (P=7.616 hour)
0 0.1 0.2 0.3 0.4 02/04-1.05m Schmidt 02/05-0.36m Miyasaka 02/11-0.36m Miyasaka
0.6 0
1
2
3
4
5
6
-0.2
0
0.2
11/12-1.05m Schmidt 11/13-1.05m Schmidt 11/15-1.05m Schmidt
0.4 10
12
14
16
18
obs time (corrected light time) [hour]
Fig. 10. Composite rotational lightcurve of the asteroid (6331) 1992 FZ1 .
0.5
10285 Renemichelsen
-0.4
8
rotational period [hour]
-0.1
[Vol. ,
7
rotational period [hour]
Fig. 11. Composite rotational lightcurve of the asteroid (8645) 1988 TN.
Fig. 12. Composite rotational lightcurve of the asteroid (10285) Renemichelsen.
Vesta family (Moth´e-Diniz et al. 2005). Thermal observations of this asteroid have indicated that it has an effective diameter of 3.91 km (Masiero et al. 2011). The period of this asteroid was not known before this study. Renemichelsen was observed during its apparition in November 2004 (Fig. 12). Although (10285) Renemichelsen was observed for three nights, determination of its rotational period was not possible due to its small amplitude. 3.1.13. (10320) Reiland The asteroid (10320) Reiland is a Vestoid (Duffard et al. 2004) and a member of the Vesta family (Moth´eDiniz et al. 2005). The diameter of this asteroid is 2.86 km (Masiero et al. 2011), but the period of this asteroid was not known prior to this study. Reiland was observed during its apparition in November 2004 (Fig. 11), and a rotational period of 5.92 ± 0.01 h was determined. The asteroid is valued as U = 2−. 3.2.
The asteroid is assessed at U = 2+. 3.1.11. (8645) 1988 TN The asteroid (8645) 1988 TN is a V-type asteroid (Roig & Gil-Hutton 2006), but is not a member of the Vesta family (Moth´e-Diniz et al. 2005). However, the asteroid is positioned in the inner main belt region. Masiero et al. (2011) determined the diameter of this asteroid to be 5.08 km. The period of this asteroid was not known before this study. 1988 TN was observed during its apparition in February 2005 (Fig. 11) and a rotational period of 7.616 ± 0.002 h determined for this asteroid. The asteroid is rated as U = 3−. 3.1.12. (10285) Renemichelsen The asteroid (10285) Renemichelsen has a Vesta-like spectrum (Duffard et al. 2004) and is a member of the
non-V-type asteroids
Lightcurves of some non-V-type asteroids were obtained whilst making observations of V-type asteroids. 3.2.1. (477) Italia The asteroid (477) Italia is a S-type asteroid (Tholen 1994, Bus & Binzel 2002) with a diameter of 25.02 km (Usui et al. 2011). This asteroid was observed in the same frame as (1933) Tinchen for four nights. The period of this asteroid was known prior to this study. Italia was observed during its apparition in 2004 (Fig. 14) and a rotational period of 19.32 ± 0.01 h obtained. On the website of Behrend, the rotational period for this asteroid is reported to be 19.42 h, which is consistent with our results. The asteroid is estimated as U = 2−.
Lightcurve Survey of V-type Asteroids -0.2
10320 Reiland (P=5.920 hour) -0.1 0 0.1 0.2 0.3 11/12-1.05m Schmidt 11/13-1.05m Schmidt 11/15-1.05m Schmidt
0.4 0
1
2
3
4
5
10389 Robmanning (P=2.75 hour) 0
0.05
0.1
11/15-1.05m Schmidt
0.15 0
6
rotational period [hour]
1
1.5
2
2.5
3
Fig. 15. Composite rotational lightcurve of the asteroid (10389) Robmanning.
relative magnitude (!=0º) [mag]
0
0.5
rotational period [hour]
Fig. 13. Composite rotational lightcurve of the asteroid (10320) Reiland.
relative magnitude (!=0º) [mag]
7
-0.05
relative magnitude (!=0º) [mag]
relative magnitude (!=0º) [mag]
No. ]
477 Italia (P=19.32 hour)
-0.1
10443 van der Pol (P=3.32 hour)
-0.05
0.05 0.1 0.15 0.2 0.25
03/07-1.05m Schmidt 03/08-1.05m Schmidt 03/12-0.36m Miyasaka 03/13-0.36m Miyasaka
0.3 0
5
10
15
20
rotational period [hour]
0 0.05 0.1 0.15 0.2 0.25 11/15-1.05m Schmidt
0.3 0
0.5
1
1.5
2
2.5
3
3.5
rotational period [hour]
Fig. 14. Composite rotational lightcurve of the asteroid (477) Italia.
Fig. 16. Composite rotational lightcurve of the asteroid (10443) van de Pol.
3.2.2. (10389) Robmanning The spectral type of asteroid (10389) Robmanning is unknown. The diameter of the asteroid has been estimated to be 4.12 km (Masiero et al. 2011). This asteroid was monitored in the same frame as (11320) Reiland for one night. The period of this asteroid was not known before this study. Robmanning was observed during its apparition in March 2004 (Fig. 15) and yielded a rotational period of 2.75 h. The asteroid is evaluated with U = 2−.
November 2004 (Fig. 16) and gave a rotational period of 3.32 h. The website of Pravec et al. reports a rotational period of 3.34501 h for this asteroid, which is consistent with our result. The asteroid is rated as U = 2−.
3.2.3. (10443) van de Pol The asteroid (10443) van de Pol is an S-type asteroid (Ivezi´c et al. 2002). Masiero et al. (2011) reported that the diameter of this asteroid is 3.44 km. The asteroid was observed in the same frame as (11320) Reiland for one night. van de Pol was observed during its apparition in
3.2.4. (11321) Tosimatsumoto The spectrum of asteroid (11321) Tosimatsumoto classifies it as XL-type (Carvano et al. 2010), which has a diameter of 9.19 km (Masiero et al. 2011). This asteroid was monitored in the same frame as (8645) 1988 TN for two nights. The period of this asteroid was not known before this study. Tosimatsumoto was observed during its apparition in February 2005 (Fig. 17) and a rotational period of 7.80 ± 0.09 h was obtained. The asteroid is assessed at U = 1+.
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Fig. 17. Composite rotational lightcurve of the asteroid (11321) Tosimatsumoto.
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Fig. 18. Composite rotational lightcurve of the asteroid (18590) 1997 YO10
Fig. 20. Composite rotational lightcurve of the asteroid (22034) 1999 XL168
3.2.5. (18590) 1997 YO10 The asteroid (18590) 1997 YO10 is an S-type asteroid (Ivezi´c et al. 2002; Carvano et al. 2010). Thermal observations of this asteroid have shown that it has an effective diameter of 5.02 km (Masiero et al. 2011). The asteroid was monitored in the same frame as (2011) Veteraniya for one night. The period of this asteroid was not known prior to this study. 1997 YO10 was observed during its apparition in November 2004 (Fig. 18), yielding a rotational period of ∼2.95 h. The asteroid is evaluated with U = 1.
The period of this asteroid was not known prior to this study. 1999 XL168 was observed during its apparition in November 2004 (Fig. 19), and resulted in a calculated rotational period of ∼3.35 h. The asteroid is estimated as U = 1.
3.2.6. (22034) 1999 XL168 The spectral type of asteroid (22034) 1999 XL168 is unknown. This asteroid has an effective diameter of 5.15 km (Masiero et al. 2011). (22034) 1999 XL168 was monitored in the same frame as (2011) Veteraniya for one night.
3.2.7. (29976) 1999 NE6 The asteroid (29976) 1999 NE6 is a D-type asteroid (Carvano et al. 2010). The diameter of this asteroid has been estimated to be 9.56 km (Masiero et al. 2011). This asteroid was observed in the same frame as (3900) Knezevic for two nights. The period of this asteroid was not known before this study. 1999 NE6 was observed during its apparition in January 2005 (Fig. 20). Despite two nights of observations, a solution for the rotational period of this asteroid was not possible due to its small amplitude.
Lightcurve Survey of V-type Asteroids -0.2
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3.2.9. (46121) 2001 FB36 The asteroid (46121) 2001 FB36 is a C-type asteroid (Ivezi´c et al. 2002; Carvano et al. 2010). Masiero et al. (2011) reported that the diameter of this asteroid is 6.26 km. This asteroid was observed in the same frame as (3900) Knezevic for two nights. The period of this asteroid was not known prior to this study. 2001 FB36 was observed during its apparition in January 2005 (Fig. 22) and a rotational period of ∼4.2 h was determined. The asteroid is assessed at U = 1.
Discussion
We have now determined the rotational rate of 59 Vtype asteroids in the inner main belt, which includes our 11 new and 48 previous results (Table 2). The diameters
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Fig. 22. Composite rotational lightcurve of the asteroid (46121) 2001 FB36
3.2.8. (41051) 1999 VR10 The spectral type of asteroid (41051) VR10 is unknown. The diameter of the asteroid has been estimated to be 11.12 km (Masiero et al. 2011). The asteroid was monitored in the same frame as (11320) Reiland for one night. The period of this asteroid was not known prior to this study. 1999 VR10 was observed during its apparition in November 2004 (Fig. 21), yielding a rotational period of 4.04 h. The asteroid is evaluated with U = 2−.
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Fig. 21. Composite rotational lightcurve of the asteroid (41051) 1999 VR10
3.2.10. (89481) 2001 XH27 (89481) XH27 is an X-type asteroid (Carvano et al. 2010) with an albedo that is the same as the median value of X-type asteroids (Mainzer et al. 2012). The size of this asteroid is ∼ 2.8 km. The Jupiter Trojan asteroid was monitored in the same frame as (4434) Nikulin for two nights. The period of this asteroid was not known before this study. 2001 XH27 was observed during its apparition in October 2005 (Fig. 23). Although observed for two nights, its rotational period was not able to be determined due to its small amplitude.
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Fig. 23. Composite rotational lightcurve of the asteroid (89481) 2001 XH27
of these asteroids range from 3 to 10 km, respectively, on the basis of an assumed albedo of the median value of V-type asteroids. Figure 24 is a histogram of the rotational rate for the 59 V-type asteroids in the inner main belt and 29 V-type Vesta family asteroids, excluding 4 Vesta. Both V-type Vesta family asteroids and V-type asteroids in the inner main belt exhibit a non-Maxwellian distribution compared with the Maxwellian distribution expected for a collisionally evolved population. There is certainly present an observational bias against slow rotators with spin rates slower than 1 rev/day and probably also against asteroids with spin rates faster than 7 rev/day. Measurements of rotation periods for slow ro2 3 4
hhttp://obswww.unige.ch/∼behrend/page cou.htmli. hhttp://www.minorplanetobserver.com/PDO/PDOLightcurves.htmi. hhttp://www.asu.cas.cz/∼ppravec/neo.htmi.
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Fig. 24. Distribution of rotational rates for V-type asteroids in the inner main belt. (a) only V-type Vesta family asteroids. (b) all V-type asteroids. Asteroid 4 Vesta has been excluded from this figure. The dashed curve represents the best-fit Maxwellian distribution.
tators as well as for low amplitude ones are more difficult than for asteroids with more ordinary periods between 4 and 24 hours. Fast rotators with more than 7 rev/day close to the spin rate barrier that is at f about 10 rev/day tend to have spheroidal shapes and thus lower lightcurve amplitudes. Therefore, there become fewer data of these asteroids than real distribution. Taking into account observational bias, the real distributions of V-type Vesta family asteroids and V-type asteroids in the inner main belt are more different from Maxwellian distribution. Slivan et al. (2008) showed that the distribution of rotation rates of the Koronis family is non-Maxwellian. Vokrouhlick´ y et al. (2003) suggested that the rotation rates and obliquities of the spin vector for the Koronis family have been influenced by YORP effects for several billion years. The timescale of YORP effects for the Koronis family is consistent with the age of the Koronis family as estimated by numerical simulations (Marzari et al. 1999), crater counting of the Koronis family aster-
[Vol. ,
oid 243 Ida (Greenberg et al. 1996), and age–color relationships from photometric observations (Nesvorn´ y et al. 2005). Kryszczyn´ska et al. (2012) showed that the rotational rates of the Flora family also have a nonMaxwellian distribution. This result clearly demonstrates the influence of YORP effects on the Flora family. The age of the Flora family (Nesvorn´ y et al. 2005) is also consistent with the timescale of YORP effects. Pravec et al. (2008) showed that the distribution of main belt and Mars-crossing asteroids with diameters of 3–15 km has a non-Maxwellian distribution due to YORP torques. In light of these examples of other asteroid families, it is probable that the rotational rate distribution of Vtype asteroids can be explained by long-term modification by YORP torques. The YORP effect is dependent on asteroid size, shape, spin vector, and heliocentric distance (Rubincam 2000). As such, we speculate that the timescale for generation of V-type asteroids with 3 < Diameter < 10 km ranges from sub-billion to several ∼ ∼ billion years. The results of Marzari et al. (1996) indicate that the cratering event that formed the Vesta family occurred ∼1 Gyr ago. Carruba et al. (2007) implied the Vesta family age is (1.2 ± 0.7) Gyr in age. The Dawn spacecraft scanned the surface of Vesta and the two largest impact craters were estimated to have formed about 1 Gyr ago (Marchi et al. 2012). Nesvorn´ y et al. (2008) also suggested that the Vesta family has existed for at least ∼1 Gyr and, if members of the Vesta family were liberated from the surface of Vesta, that the impact event occurred at 3.8 Gyr. Using a collisional evolution model Bottke et al. (2005), determined with a 19% probability that a major impact has occurred on asteroid (4) Vesta and produced the Vesta family in the last 3.5 Gyr. Several large impact-heating events have also been shown to have occurred on the asteroid 4 Vesta between 3.4 and 4.5 Gyr ago through Ar–Ar radiometric dating of eucrites (Bogard & Garrison 2003). In summary, the timescale for formation of the Vesta family and ejecta from Vesta, if YORP effects are invoked to explain their rotational rate distribution, is consistent with dating of HED meteorites, numerical simulations of the Vesta family, and crater counting of Vesta by the Dawn mission. 5.
Conclusions
We have determined the rotational rate of a number of V-type asteroids in the inner main belt: (1933) Tinchen, (2011) Veteraniya, (2508) Alupka, (3657) Ermolova, (3900) Knezevic, (4005) Dyagilev, (4383) Suruga, (4434) Nikulin, (4796) Lewis, (6331) 1992 FZ1 , (8645) 1998 TN, (10285) Renemichelsen, and (10320) Reiland. Lightcurves in the R-band of rotation periods were found for Tinchen, Veteraniya, Alupka, Ermolova, Knezevic, Dyagilev, Suruga, Lewis, 1992 FZ1 , 1998 TN, and Reiland. A compilation of rotational rates of 59 Vtype asteroids in the inner main belt shows that the rotation rate distribution is non-Maxwellian, which may be explained by the long-term effect of YORP torques.
No. ]
Lightcurve Survey of V-type Asteroids
We would like to express our gratitude to staff members of Kiso Observatory, Misato Observatory, and UH88 for their support during lightcurve observations. We are grateful to Richard Binzel and Julian Oey for sharing with us valuable information about V-type asteroids. This work was partially supported by the Japan Society for the Promotion of Science under a Grant-in-Aid for Scientific Research (B) 17340133. This study was partially supported by the Space Plasma Laboratory, ISAS, and JAXA as a collaborative research program. References Alvarez-Candal, A., Duffard, R., Lazzaro, D., & Michtchenko, T. 2006, A&A, 459, 969 Albers, K., Kragh, K., Monnier, A., Pligge, Z., Stolze, K., West, J., Yim, A., & Ditteon, R. 2010, Minor Planet Bul., 37, 152 Alvarez-Candal, A., Duffard, R., Lazzaro, D., & Michtchenko, T. 2006, A&A, 459, 969 Behrend, R., Bernasconi, L., Klotz, A., & Durkee, R. IAU Circ., 8389, 2 Binzel, R. P. 1987, Icarus, 72, 135 Binzel, R. P., & Xu S. 1993, Science, 260, 186 Binzel, R. P., Harris, A. W., Bus, S. J., & Burbine, T. H. 2001, Icarus, 151, 139 Binzel, R. P., Perozzi, E., Rivkin, A. S., Rossi, A., Harris, A. W., Bus, S. J., Valsecchi, G. B., & Slivan, S. M. 2004a, Meteor. Planet. Sci, 39, 351 Binzel, R. P., Rivkin, A. S., Stuart, J. S., Harris, A. W., Bus, S. J., & Burbine, T. H. 2004b, Icarus, 170, 259 Binzel, R. P., Xu, S., Bus, S. J., & Bowell, E. 1992, Icarus, 99, 225 Bogard, D. D. & Garrison, D. H. 1993, Meteor. Planet. Sci., 38, 669 Bottke, W. F., Durada, D. D., Nesvorn´ y, D., Jedicke, R., Morbidelli, A., Vokrouhlick´ y, D., & Levison., H., 2005, Icarus, 175, 111 Brinsfield, J. W. 2008, Minor Planet Bul., 35, 119 Bus S. J., & Binzel R. P. 2002, Icarus, 158, 146 Carbo, L., et al. 2009, Minor Planet Bul., 36, 152 Carruba, V., Roig, F., Michtcheno, T. A., Ferraz-Mello, S. F., & Nesvorn´ y, D. 2007, A&A, 465, 315 Carvano, J. M., Hasselmann, P. H., Lazzaro, D., & Moth´eDiniz, T. 2012, A&A, 510, A43 Cruikshank, D. P., Tholen, D. J. Hartmann, W. K. Bell, J. F., & Brown, R. H. 1991, Icarus, 89, 1 Davies, J. K., Harris, A. W., Rivkin, A. S., Wolters, S. D., Green. S. F., McBridge, N., Mann, R. K., & Kerr, T. M. 2007, Icarus, 186, 111 de Le´ on, J., Lincandro, J., Duffard, R., & Serra-Ricart, M. 2006, Adv. Space Res., 37, 178 Duffard, R., de Le´ on, J., Licandro, J., Lazzaro, D., & SerraRicart, M. 2006, A&A, 456, 775 Duffard, R., Lazzaro, D., Lincandro, J., De Sacctis, M. C., Capria, M. T., & Carvaro, J. M. 2004, Icarus, 171, 120 ˘ Durech, J., et al. 2011, Icarus, 214, 652 Durkee, R. I., & Pravec, P. 2007, Minor Planet Bul., 34, 49 Gal´ ad, A., Pravec, P., Ku˘snir´ ak, P., Gajdo˘s, S., Korno˘s, L., & Vil´ agi, J. 2005, Earth Moon Planets, 97, 147 Gladman, B. J. et al. 1997, Science, 277, 197 Greenberg, R., Bottke, W. F., Nolan, M., Geissler, P., Petit, J.-M., Durada, D. D., Asphaug, E., & Head, J., 1996, Icarus, 120, 106
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The paper is readable at hhttp://arxiv.org/abs/1204.0548i.
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[Vol. ,
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13
Table 1. Observational conditions.∗
NUM
NAME
1933 1933 1933 1933 477 477 477 477 2011 2011 2011 18590 22034 2508 2508 2508 3657 3657 3657 3900 3900 3900 3900 29976 29976 46121 46121 4005 4005 4005 4383 4383 4434 4434 4434 89481 89481 4796 4796 4796 4796 6331 6331 6331 6331 8645 8645 8645 11321 11321 10285 10285 10285 10320 10320
Tinchen Tinchen Tinchen Tinchen Italia Italia Italia Italia Veteraniya Veteraniya Veteraniya 1997 YO10 1999 XL168 Alupka Alupka Alupka Ermolova Ermolova Ermolova Knezevic Knezevic Knezevic Knezevic 1999 NE6 1999 NE6 2001 FB36 2001 FB36 Dyagilev Dyagilev Dyagilev Suruga Suruga Nikulin Nikulin Nikulin 2001 XH27 2001 XH27 Lewis Lewis Lewis Lewis 1992 FZ1 1992 FZ1 1992 FZ1 1992 FZ1 1988 TN 1988 TN 1988 TN Tosimatsumoto Tosimatsumoto Renemichelsen Renemichelsen Renemichelsen Reiland Reiland
Type V V V V S S S S V V V S V V V V V V V V V V D D C C V V V V V V V V X X V V V V V V V V V V V XL XL V V V V V
Date 2005.3.7 2005.3.8 2005.3.12 2005.3.13 2005.3.7 2005.3.8 2005.3.12 2005.3.13 2004.11.12 2005.1.8 2005.1.9 2004.11.12 2004.11.12 2004.11.12 2004.11.13 2004.11.15 2005.5.5 2005.5.9 2005.5.14 2005.1.16 2005.1.17 2005.1.18 2005.2.4 2005.1.16 2005.1.17 2005.1.16 2005.1.17 2005.3.7 2005.3.8 2005.3.13 2004.12.17 2004.12.20 2004.10.15 2004.10.16 2004.10.17 2004.10.16 2004.10.17 2004.9.15 2004.10.1 2004.10.14 2004.10.15 2004.10.15 2004.10.16 2004.10.17 2004.11.6 2005.2.4 2005.2.5 2005.2.11 2005.2.4 2005.2.5 2004.11.12 2004.11.13 2004.11.15 2004.11.12 2004.11.13
Duration [hr] 6.3 4.9 4.2 6.4 6.3 4.9 4.2 6.4 3.6 8.6 9.1 3.6 3.6 8.7 4.1 8.2 0.5 1.6 2.0 2.1 2.5 1.1 7.5 2.1 2.5 2.1 2.5 6.7 3.3 3.3 3.2 2.1 6.2 7.7 7.7 7.7 7.7 1.9 2.6 3.9 1.4 3.5 1.4 5.7 1.7 3.4 7.4 7.0 2.0 7.4 2.8 5.9 8.1 8.8 5.1
Rh [AU] 2.611 2.611 2.613 2.614 2.824 2.823 2.820 2.819 2.563 2.633 2.634 2.566 2.589 2.461 2.462 2.464 2.538 2.534 2.529 2.342 2.344 2.346 2.372 5.114 5.114 2.891 2.891 2.801 2.800 2.798 2.281 2.282 2.119 2.119 2.119 1.826 1.826 1.983 2.003 2.021 2.022 2.171 2.172 2.173 2.200 2.471 2.471 2.475 3.255 3.255 2.374 2.376 2.378 2.310 2.312
∆ [AU] 1.632 1.63 1.623 1.622 1.846 1.842 1.830 1.827 2.213 1.694 1.691 2.213 2.237 1.531 1.528 1.521 1.716 1.749 1.794 1.386 1.384 1.382 1.393 4.169 4.164 1.940 1.935 1.832 1.829 1.817 1.382 1.401 1.127 1.127 1.127 0.834 0.833 1.033 1.008 1.030 1.033 1.191 1.194 1.197 1.309 1.491 1.491 1.493 2.277 2.276 1.449 1.455 1.470 1.328 1.329
α [◦ ] 4.7 4.2 2.4 2.0 4.3 4.0 2.2 1.8 22.4 7.9 7.5 22.4 22.2 10.1 9.7 8.8 16.1 17.3 18.7 7.3 6.8 6.3 3.8 3.4 3.2 6.0 5.6 5.5 5.2 4.0 13 14.1 4.0 3.6 3.4 4.4 4.0 13.3 4.4 4.5 5.0 6.6 6.8 7.1 14.7 3.5 3.2 3.1 2.6 2.4 10.9 11.2 12.0 3.9 3.7
Telescope
Band
1.05 m - Kiso 1.05 m - Kiso 0.36 m - Miyasaka 0.36 m - Miyasaka 1.05 m - Kiso 1.05 m - Kiso 0.36 m - Miyasaka 0.36 m - Miyasaka 1.05 m - Kiso 0.36 m - Miyasaka 0.36 m - Miyasaka 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 0.36 m - Miyasaka 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 0.36 m - Miyasaka 1.05 m - Misato 2.24 m - UH88 0.36 m - Miyasaka 0.36 m - Miyasaka 0.36 m - Miyasaka 0.36 m - Miyasaka 0.36 m - Miyasaka 1.05 m - Misato 0.36 m - Miyasaka 0.30 m - Kiso 0.30 m - Kiso 0.30 m - Kiso 0.50 m - Okayama 0.50 m - Okayama 0.36 m - Miyasaka 1.05 m - Kiso 0.36 m - Miyasaka 0.36 m - Miyasaka 1.05 m - Kiso 0.36 m - Miyasaka 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso
R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R
14
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Table 1. (Continued.)
NUM 10320 10389 10443 41051 ∗
NAME Reiland Robmanning van de Pol 1999 VR10
Type V S
Date 2004.11.15 2004.11.15 2004.11.15 2004.11.15
Duration 8.3 8.3 8.3 8.3
Rh 2.315 1.950 2.028 2.665
∆ 1.331 0.966 1.045 1.684
α 3.6 4.1 4.2 3.2
Telescope 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso 1.05 m - Kiso
Band R R R R
The heliocentric distance (Rh ), geocentric distance (∆), and phase angle (α) for observing asteroids were obtained through the JPL HORIZON ephemeris generator system of NASA1 .
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Lightcurve Survey of V-type Asteroids
15
Table 2. Rotational properties and orbital elements for V-type asteroids in the inner main belt.
NUM NAME
Spin rate [rev/day] 809 Lundia 1.56 854 Frostia 0.64 956 Elisa 6.17 1273 Helma 3.94 1906 Naef 2.18 1929 Kollaa 8.03 1933 Tinchen 6.54 1946 Walraven 2.35 2011 Veteraniya 2.92 2113 Ehrdni 1.82 2442 Corbett 2.40 2486 Metsahovi 5.39 2508 Alupka 1.36 2511 Patterson 5.79 2579 Spartacus 6.60 2590 Mourao 1.54 2640 Hallstrom 1.05 2653 Principia 4.35 2763 Jeans 3.08 2768 Gorky 5.33 2795 Lepage 0.40 2851 Harbin 4.43 2912 Lapalma 4.20 3155 Lee 2.89 3268 De Sanctis 1.41 3307 Athabasca 4.90 3376 Armandhammer 3.03 3536 Schleicher 4.15 3657 Ermolova 9.30 3703 Volkonskaya 7.42 3782 Celle 6.25 3850 Peltier 9.88 3900 Knezevic 4.51 3968 Koptelov 1.15 4005 Dyagilev 3.75 4147 Lennon 0.18 4215 Kamo 1.91 4383 Suruga 6.30 4796 Lewis 6.84 4977 Rauthgundis 0.39 5111 Jacliff 8.45 5240 Kwasan 4.49 5481 Kiuchi 6.63 5524 Lecacheux 2.85 5560 Amytis 3.11 5599 1991 SG1 6.63 5754 1992 FR2 2.70 5875 Kuga 4.32 6159 1991 YH 2.26 6331 1992 FZ1 2.57 6406 1992 MJ 3.52 6877 Giada 5.75 6976 Kanatsu 5.96
Da∗ [km] 10.26WS 9.49AF 10.47WS 10.39WS 8.06WS 7.77WS 6.45WS 9.21WS 5.19WS 5.20KA 8.33W3 8.42WS 5.17WS 7.85WS 4.60WS 7.88W4 5.70KA 9.88W3 7.52WS 10.79WS 6.14W3 8.84W3 6.52W3 6.85WS 6.03WS 3.63W3 8.17WS 3.64WS 5.80AF 3.73WS 5.92WS 3.77KA 4.96WS 5.97KA 8.36WS 5.17WS 6.55W3 6.47WS 5.20KA 3.86WS 6.69WS 7.27WS 5.70KA 19.9W3 4.70WS 7.17WS 5.70WS 7.47WS 5.34WS 5.32WS 4.06W3 4.66WS 5.50WS
a [AU] 2.2829 2.3682 2.2982 2.3935 2.3732 2.3630 2.3527 2.2934 2.3863 2.4730 2.3874 2.2687 2.3682 2.2985 2.2104 2.3431 2.3981 2.4444 2.4049 2.2347 2.2955 2.4791 2.2896 2.3425 2.3472 2.2593 2.3487 2.3431 2.3124 2.3319 2.4148 2.2343 2.3707 2.3212 2.4511 2.3617 2.4175 2.4244 2.3553 2.2924 2.3542 2.3831 2.3400 2.3662 2.2856 2.4195 2.2676 2.3792 2.2916 2.3585 2.2758 2.3231 2.3334
e 0.1925 0.1740 0.2038 0.1622 0.1351 0.0746 0.1229 0.2352 0.1502 0.0970 0.1182 0.0797 0.1276 0.1039 0.0753 0.1173 0.0883 0.0800 0.2174 0.1713 0.0283 0.1229 0.0707 0.1011 0.1264 0.0955 0.0661 0.0492 0.1324 0.1340 0.0943 0.1621 0.1376 0.0923 0.1497 0.0802 0.0619 0.0630 0.1803 0.1113 0.1266 0.1004 0.0625 0.0284 0.1084 0.1337 0.1416 0.0492 0.0618 0.1338 0.1774 0.1344 0.1694
i Spectrum Vesta Lightcurve [◦ ] refference† family literature 7.14 S3,D4 Kryszczy´ nska et al. (2009) 6.09 AC Behrend et al. (2004) 5.96 S3,D4 Behrend, R. website2 5.42 SM1 1 Higgins & Goncalves (2007) 6.47 SM1 1 Durkee & Pravec (2007) 7.78 SM1 1 Behrend, R. website2 6.88 SM1 1 This work 8.17 AC Van Gent (1993) 6.20 SM1 1 This work 6.44 SM1 Binzel (1987) 5.09 SM1 Behrend, R. website2 8.41 AC Pikler et al. (2007) 6.08 SM2 1 This work 8.05 SM2 1 Hasegawa et al. (in press) 5.78 SM2 Warner, B.D. website3 6.12 SM1 1 Gal´ad et al. (2005) 6.65 SM2,RG Hasegawa et al. (in press) 4.74 SM2 Hasegawa et al. (in press) 3.54 SM2,D4 Stephens (2013) 6.28 AC Pray et al. (2008) 6.03 SM2 Hasegawa et al. (in press) 8.55 SM2,D4 Albers et al. (2010) 7.28 SM2 Brinsfield (2008) 7.20 SM1,SM2,D4 1 Warner (2003) 6.35 SM1,D4 1 Wisniewski (1991) 6.37 SM2 1 Hasegawa et al. (in press) 6.35 SM2 1 Pravec, P. et al. website4 6.56 SM2 Binzel et al. (1992) 5.79 SM1 1 This work 6.74 BP 1 Ryan et al. (2004a) 5.25 SM2,RG 1 Ryan et al. (2004b) 5.27 SM2 Oey et al. (2007) 6.73 SM2 1 This work 6.21 SM1 1 Behrend, R. website2 6.84 SM1 This work 5.74 SM1 1 Hasegawa et al. (in press) 5.75 SM2 1 Wetterer et al. (1999) 7.15 RG This work 2.27 SM2,D4 This work 5.88 SM2 Hasegawa et al. (in press) 5.81 RG 1 Behrend, R. website2 5.61 SM2 1 Ivanova et al. (2002) 5.96 S3,RG 1 Ku˘snir´ak et al. (2008) 7.49 CA Pravec, P. et al. website4 5.62 RG Hawkins & Ditteon (2008) 6.46 RG Willis (2004) 5.54 CA Behrend, R. website2 6.47 CA Carbo et al. (2009) 6.86 D4 1 Warner (2006) 7.76 D4 1 This work 8.17 AC Higgins & Goncalves (2007) 6.18 RG 1 Behrend, R. website2 8.25 CA Carbo et al. (2009)
16
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Table 2. (Continued.)
NUM 8645 10320 17035 19979 35062 45073
NAME 1988 TN Reiland Velichko 1989 VJ Sakuranosyou Doyanrose
rate 3.15 4.05 8.28 3.17 1.26 7.59
Da 5.08WS 2.86WS 4.76WS 6.85KA 3.21WS 2.73KA
a [AU] 2.4311 2.2881 2.4440 2.4588 2.3695 2.3336
e 0.0608 0.1340 0.1463 0.1023 0.2388 0.1479
i [◦ ] 5.28 6.34 6.24 5.17 10.51 6.91
spectrum RG D4 RG RG CA CA
family literature This work 1 This work 1 Behrend, R. website2 1 Han et al. (2013) Pravec, P. et al. website4 1 Ruthroff (2011)
∗ References for diameter. AF Usui et al. (2011); WS Masiero et al. (2011); W3 Masiero et al. (2012); KA assuming albedo is the same as the median value of V-type asteroids (pv = 0.343; Mainzer et al. 2012). † References for spectral type. AC: Alvarez-Candal et al. (2006); BP: Binzel, R.P. private comm. CA: Carvano et al. (2010); D4: Duffard et al. (2004); D6: Duffard et al. (2006); RG: Roig & Gil-Hutton (2006); SM1: Xu et al. (1995); SM2: Bus & Binzel (2002); S3: Lazzaro et al. (2004).
