The dust environment of main-belt comet P/2010 R2 (LA SAGRA)

Abstract

We present a model of the dust environment of Main-Belt Comet P/2010 R2 (La Sagra) from images acquired during the period 2010 October-2011 January. The tails are best simulated by anisotropic ejection models, with emission concentrated near the nucleus south pole, the spin axis having an obliquity near 90°, indicative of a possible seasonally driven behavior. The dust mass loss rate increases rapidly shortly before perihelion, reaching a maximum value of 4kgs-1, and maintaining a sustained, cometary-like, activity of about 3-4kgs-1 up to at least 200days after perihelion, the date of the latest observation. The size distribution function is characterized by particles in the 5 × 10-4cm to 1cm radius range, assuming a time-constant power-law distribution with an index of -3.5. The ejection velocities are compatible with water-ice sublimation activity at the heliocentric distance of 2.7AU, with values of 10-20cms-1 for particle radius of 1cm, and inverse square root dependence on particle size, typical of hydrodynamical gas drag. © 2011. The American Astronomical Society. All rights reserved.