Olivine-Dominated A-Type Asteroids in the Main Belt: Distribution, Abundance and Relation to Families
Olivine-dominated A-type asteroids in the Main Belt: Distribution, Abundance and Relation to Families Francesca E. DeMeoa, David Polishookb, Benoˆıt Carryc, Brian J. Burtd, Henry H. Hsiehe,f, Richard P. Binzela, Nicholas A. Moskovitzd, Thomas H. Burbineg aDepartment of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 USA bDepartment of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 0076100, Israel cObservatoire de la Cte d’Azur, Boulevard de l’Observatoire, 06304 Nice Cedex 4, France dLowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA ePlanetary Science Institute, 1700 E. Ft. Lowell Road, Suite 106, Tucson, AZ 85719, USA fInstitute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan gDepartment of Astronomy, Mount Holyoke College, South Hadley, MA 01075, USA Abstract Differentiated asteroids are rare in the main asteroid belt despite evidence for ∼100 distinct differentiated bodies in the meteorite record. We have sought to understand why so few main-belt asteroids differentiated and where those differentiated bodies or fragments reside. Using the Sloan Digital Sky Survey (SDSS) to search for a needle in a haystack we identify spectral A-type asteroid candidates, olivine-dominated asteroids that may represent mantle material of differentiated bodies. We have performed a near-infrared spectral survey with SpeX on the NASA IRTF and FIRE on the Magellan Telescope. We report results from having doubled the number of known A-type asteroids. We deduce a new estimate for the overall abundance and distribution of this class of olivine-dominated asteroids.
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