The catastrophic fragmentation of Comet 332P (Ikeya-Murakami)

Abstract

We describe 2016 January to April observations of the fragments of 332P/Ikeya-Murakami, a comet earlier observed in a 2010 October outburst (Ishiguro et al 2014). We present photometry of the fragments, and perform simulations to infer the time of breakup. We argue that the eastern-most rapidly brightening fragment ($F4$) best corresponds to the original nucleus, rather than the initial bright fragment $F1$. We compute radial and tangential non-gravitational parameters, $A_1=(1.5\pm 0.4)\times 10^{-8}$ AU day${}^{-2}$ and $(7.2\pm 1.9)\times 10^{-9}$ AU day${}^{-2}$; both are consistent with zero at the $4\sigma$ level. Monte Carlo simulations indicate that the fragments were emitted on the outbound journey well after the 2010 outburst, with bright fragment $F1$ splitting in mid--2013 and the fainter fragments within months of the 2016 January recovery. Western fragment $F7$ is the oldest, dating from 2011. We suggest that the delayed onset of the splitting is consistent with a self-propagating crystallization of water ice.

8 pages, 4 figures, published in ApJ Letters

References in corpus (3)

• When Comets Get Old: A Synthesis of Comet and Meteor Observations of the Low Activity Comet 209P/LINEAR
• An Early Look of Comet C/2013 A1 (Siding Spring): Breathtaker or Nightmare?
• Outbursting Comet P/2010 V1 (Ikeya-Murakami): A Miniature Comet Holmes

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