The Dust Environment of Main-Belt Comet P/2010 R2 (La Sagra)

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 ~4 kg s[SUP]-1[/SUP], and maintaining a sustained, cometary-like, activity of about 3-4 kg s[SUP]-1[/SUP] up to at least 200 days after perihelion, the date of the latest observation. The size distribution function is characterized by particles in the 5 × 10[SUP]-4[/SUP] cm to 1 cm 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 2.7 AU, with values of 10-20 cm s[SUP]-1[/SUP] for particle radius of 1 cm, and inverse square root dependence on particle size, typical of hydrodynamical gas drag.