P/2010 A2 LINEAR

II. Dynamical dust modelling

J. Kleyna¹, O. R. Hainaut² and K. J. Meech¹

¹ Institute for Astronomy (IfA), University of Hawai’i, 2680 Woodlawn Drive, Honolulu HI 96822, USA
e-mail: kleyna@ifa.hawaii.edu
² European Southern Observatory (ESO), Karl Schwarzschild Straße, 85748 Garching bei München, Germany
e-mail: ohainaut@eso.org

Received: 10 November 2011
Accepted: 25 August 2012

Abstract

P/2010 A2 is an object on an asteroidal orbit that was observed to have an extended tail or debris trail in January 2010. In this work, we fit the outburst of P/2010 A2 with a conical burst model, and verify previous suspicions that this was a one-time collisional event rather than a sustained cometary outburst, implying that P/2010 A2 is not a new main belt comet driven by ice sublimation. We find that the best-fit cone opening angle is ~40° to ~50°, in agreement with numerical and laboratory simulations of cratering events. Mapping debris orbits to sky positions suggests that the distinctive arc features in the debris correspond to the same debris cone inferred from the extended dust. From the velocity of the debris, and from the presence of a velocity maximum at around 15 cm s^-1, we infer that the surface of A2 probably has a very low strength (≲1 kPa), comparable to lunar regolith.