TY - JOUR
T1 - The Main Belt Asteroid Shape Distribution from Gaia Data Release 2
AU - Mommert, Michael
AU - McNeill, Andrew
AU - Trilling, David E.
AU - Moskovitz, Nicholas
AU - Delbo, Marco
N1 - Funding Information:
The authors would like to thank an anonymous referee for a thorough review that improved the quality of this work significantly. This work is supported in part by NSF award 1229776. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa. int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC;https://www.cosmos.esa.int/web/gaia/ dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research has made use of the VizieR catalog access tool, CDS, Strasbourg, France. The original description of the VizieR service was published in A&AS 143, 23. This work made use of sbpy (http://sbpy.org), a community-driven Python package for small-body planetary astronomy supported by NASA PDART grant No. 80NSSC18K0987. Facility: Gaia.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved..
PY - 2018/9
Y1 - 2018/9
N2 - Gaia Data Release 2 includes observational data for 14099 pre-selected asteroids. From the sparsely sampled G-band photometry, we derive lower-limit light curve amplitudes for 11665 main belt asteroids (MBA) in order to provide constraints on the distribution of shapes in the asteroid main belt. Assuming a triaxial shape model for each asteroid, defined through the axial aspect ratios a > b and b = c, we find an average b/a = 0.80 ± 0.04 for the ensemble, which is in agreement with previous results. By combining the Gaia data with asteroid properties from the literature, we investigate possible correlations of the aspect ratio with size, semimajor axis, geometric albedo, and intrinsic color. Based on our model simulations, we find that MBAs greater than 50 km in diameter on average have higher b/a aspect ratios (are rounder) than smaller asteroids. We furthermore find significant differences in the shape distribution of MBAs as a function of the other properties that do not affect the average aspect ratios. We conclude that a more detailed investigation of shape distribution correlations requires a larger data sample than is provided in Gaia Data Release 2.
AB - Gaia Data Release 2 includes observational data for 14099 pre-selected asteroids. From the sparsely sampled G-band photometry, we derive lower-limit light curve amplitudes for 11665 main belt asteroids (MBA) in order to provide constraints on the distribution of shapes in the asteroid main belt. Assuming a triaxial shape model for each asteroid, defined through the axial aspect ratios a > b and b = c, we find an average b/a = 0.80 ± 0.04 for the ensemble, which is in agreement with previous results. By combining the Gaia data with asteroid properties from the literature, we investigate possible correlations of the aspect ratio with size, semimajor axis, geometric albedo, and intrinsic color. Based on our model simulations, we find that MBAs greater than 50 km in diameter on average have higher b/a aspect ratios (are rounder) than smaller asteroids. We furthermore find significant differences in the shape distribution of MBAs as a function of the other properties that do not affect the average aspect ratios. We conclude that a more detailed investigation of shape distribution correlations requires a larger data sample than is provided in Gaia Data Release 2.
UR - http://www.scopus.com/inward/record.url?scp=85053147042&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85053147042&partnerID=8YFLogxK
U2 - 10.3847/1538-3881/aad338
DO - 10.3847/1538-3881/aad338
M3 - Article
AN - SCOPUS:85053147042
SN - 0004-6256
VL - 156
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
M1 - 139
ER -