331P/Gibbs

331P/Gibbs (P/2012 F5) is a small Encke-type comet and active asteroid, discovered by American astronomer Alex Gibbs.

Description

It is a rare type of comet called a main-belt comet. Although most comets come from the Oort cloud or the Kuiper belt, main-belt comets are instead members of the asteroid belt that have a coma and tail. As of 2016, it is one of only 15 known main-belt comets.

Precovery observations of 331P/Gibbs in Sloan Digital Sky Survey data were found dating to August 2004, in which the object was visible as a regular asteroid. Further observations in 2014 by the Keck Observatory showed that the comet was fractured into 5 pieces and rotating rapidly, with a rotation period of only 3.2 hours. Due to the YORP effect, 331P/Gibbs had begun to spin so quickly that, being a likely rubble pile, parts began to be thrown off, leaving a very long dust trail. This is very similar to 311P/PANSTARRS, being the best-established cause for main-belt comets along with impacts between small asteroids (such as with 596 Scheila and 354P/LINEAR).

Orbit

The orbit of 331P/Gibbs is found within the dynamically cold region of the outer asteroid belt at distances between 2.88–3.13AU (431–468millionkm) from the Sun. A 2014 study revealed that it is a member of a previously unknown extremely compact cluster of nine asteroids now known as the Gibbs cluster, which was likely formed by a catastrophic collision event of their parent body more than 1.5 million years ago. Its orbit in the outer main belt is dynamically stable over timescales of 1 billion years.

Notes

External links

• at theJPL Small-Body Database·····
• 5 December 2021 at theWayback Machine
• at Seiichi Yoshida's website
• at Gideon van Buitenen's website