The Nucleus of Main-Belt Comet 259P/Garradd

TL;DR

This paper reports on observations of main-belt comet 259P/Garradd, determining its nucleus size, phase function, and dust loss, providing insights into its physical properties and activity compared to other main-belt comets.

Contribution

The study provides the first detailed measurements of 259P/Garradd's nucleus size, phase function, and dust loss, enhancing understanding of main-belt comet characteristics.

Findings

Nucleus radius of approximately 0.30 km.

Absolute magnitude and phase slope parameters determined.

Quantified dust mass loss during active phase.

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 $H_R=19.71\pm0.05$ mag and slope parameter of $G_R=-0.08\pm0.05$ for the inactive nucleus, corresponding to an effective nucleus radius of $r_e=0.30\pm0.02$ km, assuming an $R$-band albedo of $p_R=0.05$. 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.