AVAST Survey 0.4-1.0 {\mu}m Spectroscopy of Igneous Asteroids in the Inner and Middle Main Belt

TL;DR

This study presents visible spectroscopy of 60 asteroids, mainly V-types, revealing their distribution in the inner and middle main belt, and suggesting diverse origins beyond the Vesta family.

Contribution

First large-scale spectroscopic survey of V-type asteroids in the inner and middle main belt using SDSS data for candidate selection.

Findings

47 V-types confirmed spectroscopically

Identification of V-types beyond the 3:1 resonance with Jupiter

Evidence for non-Vesta origins of some V-type asteroids

Abstract

We present the spectra of 60 asteroids, including 47 V-types observed during the first phase of the Adler V-Type Asteroid (AVAST) Survey. SDSS photometry was used to select candidate V-type asteroids for follow up by nature of their very blue $i-z$ color. 47 of the 61 observed candidates were positively classified as V-type asteroids, while an additional six show indications of a 0.9 $\mu$m feature consistent with V-type spectra, but not sufficient for formal classification. Four asteroids were found to be S-type, all of which had $i-z$ values very near the adopted AVAST selection criteria of $i-z \le -0.2$, including one candidate observed well outside the cut (at a mean $i-z$ of -0.11). Three A-type asteroids were also identified. Six V-type asteroids were observed beyond the 3:1 mean motion resonance with Jupiter, including the identification of two new V-type asteroids (63085 and 105041) at this distance. Six V-type asteroids were observed with low ($<5\deg$) orbital inclination, outside of the normal dynamical range of classic Vestoids, and are suggestive of a non-Vesta origin for at least some of the population.