Outbursting Comet P/2010 V1 (Ikeya-Murakami): A Miniature Comet Holmes
  Short-period comet P/2010 V1 (Ikeya-Murakami, hereafter V1) was discovered visually by two amateur astronomers. The appearance of the comet was peculiar, consisting of an envelope, a spherical coma near the nucleus and a tail extending in the anti-solar direction. We investigated the brightness and the morphological development of the comet by taking optical images with ground-based telescopes. Our observations show that V1 experienced a large-scale explosion between UT 2010 October 31 and November 3. The color of the comet was consistent with the Sun (g'-RC=0.61+-0.20, RC-IC=0.20+-0.20, and B-RC=0.93+-0.25), suggesting that dust particles were responsible for the brightening. We used a dynamical model to understand the peculiar morphology, and found that the envelope consisted of small grains (0.3-1 micron) expanding at a maximum speed of 500+-40 m/s, while the tail and coma were composed of a wider range of dust particle sizes (0.4-570 micron) and expansion speeds 7-390 m/s. The total mass of ejecta is ~5x10^8 kg and kinetic energy ~5x10^12 J. These values are much smaller than in the historic outburst of 17P/Holmes in 2007, but the energy per unit mass (1x10^4 J/kg) is comparable. The energy per unit mass is about 10% of the energy released during the crystallization of amorphous water ice suggesting that crystallization of buried amorphous ice can supply the mass and energy of the outburst ejecta. 
Masateru Ishiguro, David Jewitt, Hidekazu Hanayama, Fumihiko Usui,   Tomohiko Sekiguchi, Kenshi Yanagisawa, Daisuke Kuroda, ...
astro-ph.EP