Presentation #202.04 in the session Asteroid Dynamics.
Howardites, Eucrites and Diogenites are achondritic (HED) meteorites with reflectance spectra linking them to asteroid Vesta. Vesta family asteroids have orbital elements like those of Vesta, consistent with their formation in energetic cratering events. Hubble Space Telescope observations revealed one crater, the Rheasilvia basin, and the Dawn spacecraft discovered a second crater, the Veneneia basin. Given their extreme large sizes, these two basins must have produced two families of asteroids, from different surface locations and interior depths, possibly resulting in variations in the properties of the subfamilies and their associated meteorites. However, if one basin is as old as the solar system, then the asteroids from that basin may have been removed from the Main Belt by catastrophic collisions and orbital evolution driven by Yarkovsky forces. Here we show that the distributions of the orbital eccentricities and inclinations of the Vesta family are consistent with the existence of two large subfamilies. To test the reality of these putative subfamilies, we analyze their size-frequency distributions, the correlations observed between the asteroid sizes and orbital elements, and the SDSS color and the WISE albedo distributions.