The nucleus of main-belt comet 259p/Garradd

Abstract

We present observations of the main-belt comet 259P/Garradd, previously known as P/2008 R1 (Garradd), obtained in 2011 and 2012 using the Gemini North Telescope on Mauna Kea in Hawaii and the SOAR telescope at Cerro Pachon in Chile, with the goal of computing the object's phase function and nucleus size. We find an absolute magnitude of HR = 19.71 ± 0.05mag and slope parameter of GR = -0.08 ± 0.05 for the inactive nucleus, corresponding to an effective nucleus radius of re = 0.30 ± 0.02km, assuming an R-band albedo of pR = 0.05. We also revisit observations reported for 259P while it was active in 2008 to quantify the dust mass loss and compare the object with other known main-belt comets. © © 2012. The American Astronomical Society. All rights reserved..