Lightcurve Study of Vp-Type Asteroids

Clifford Hall, Room 210

A massive impact event on (4) Vesta is believed to have created the Vesta family of asteroids (Asphaug, 1997). The rotational characteristics of the Vesta family provide important clues about this event, including its timing, the make‐up of the resulting debris, the subsequent migration of members of the family into Earth‐crossing orbits, and the deposition of the Howardite‐Eucrite‐Diogenite meteorites on the Earth’s surface. This study conducted lightcurve measurements of ten Vp‐type asteroids, drawn from an asteroid taxonomy defined by Carvano et al. (2010) and based on the Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC4). These measurements identified a range of asteroid rotation periods from approximately 2.5 to 9.5 hours, as well as a potential synchronous binary system, (15121) 2000 EN14. The lightcurve results were combined with those of other V/Vp‐type asteroids available in LightCurve Database (LCDB; Warner et al., 2009), and matched with both WISE diameter/albedo (J. Masiero et al., 2011) and near‐infrared spectroscopic (Hardersen et al., 2014‐2018) data. This integrated approach identified a set of Vesta family asteroids with relatively fast spin rates, nearly spherical shapes, and loose aggregate compositions. These findings, combined with the non‐ Maxwellian shape of this population’s spin rate distribution, highlighted the importance of thermal Yarkovsky‐YORP effects on the evolution of the Vesta family.