P/2006 VW139: A Main-Belt Comet Born in an Asteroid Collision?

Abstract

In this paper we apply different methods to examine the possibility that a small group of 24 asteroids dynamically linked to main-belt comet P/2006 VW139, recently discovered by the Pan-STARRS1 survey telescope, shares a common physical origin. By applying the Hierarchical Clustering and Backward Integration methods, we find strong evidence that 11 of these asteroids form a sub-group which likely originated in a recent collision event, and that this group includes P/2006 VW139. The objects not found to be part of the 11-member sub-group, which we designate as the P/2006 VW139 family, were either found to be dynamically unstable, or these are likely interlopers which should be expected due to the close proximity of the Themis family. As we demonstrated, statistical significance of P/2006 VW139 family is >99 per cent. We determine the age of the family to be 7.5 +/- 0.3 Myr, and estimate the diameter of the parent body to be about 11 km. Results show that the family is produced by an impact which can be best characterized as a transition from catastrophic to cratering regime. The dynamical environment of this family is studied as well, including the identification of the most influential mean motion and secular resonances in the region. Our findings make P/2006 VW139 now the second main-belt comet to be dynamically associated with a young asteroid family, a fact with important implications for the origin and activation mechanism of such objects.