331P/Gibbs

{{infobox comet

|name = 331P/Gibbs (P/2012 F5)

|discoverer = A. R. Gibbs
{{small|(Mount Lemmon Survey)}}

|discovery_date = March 22, 2012

|epoch = 4 February 2012 (JD 2455961.5)

|observation_arc = 11.3 years

|obs = 148

|aphelion = 3.130 AU

|perihelion = 2.877 AU

|semimajor = 3.004 AU

|eccentricity = 0.042

|period = 5.21 years (1902 days)

|inclination = 9.740°

| asc_node = 216.86°

| arg_peri = 177.40°

|tjup = 3.229

|Earth_moid = 1.88 AU

|Jupiter_moid = 2.08 AU

|dimensions = ~2-5 km

|M1 = 12.3

|M2 = 15.4

|last_p = 29 September 2020
16 June 2015

|next_p = 2025-Dec-25{{mpc|331p}}

}}

331P/Gibbs (P/2012 F5) is a small periodic Encke-type and rare main-belt comet, discovered by American amateur 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.{{cite web|title=JPL Small-Body Database Search Engine|url=http://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=com;obj_numbered=all;OBJ_field=0;ORB_field=0;combine_mode=AND;c1_group=ORB;c1_item=Bi;c1_op=%3E%3D;c1_value=1.6;c2_group=ORB;c2_item=Bn;c2_op=%3C%3D;c2_value=4;table_format=HTML;max_rows=100;format_option=comp;c_fields=AcBhBgBjBkBlBiBnBsCkCqCnAi;.cgifields=format_option;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=combine_mode;.cgifields=ast_orbit_class;.cgifields=table_format;.cgifields=com_orbit_class&query=1|website=Jet Propulsion Laboratory|publisher=NASA|access-date=10 December 2016}}

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, P/2012 F5 had begun to spin so quickly that, being a likely rubble pile, parts began to be thrown off, leaving a very long dust trail.{{cite web|title=Active asteroid spun so fast that it exploded|url=https://astronomynow.com/2015/03/23/active-asteroid-spun-so-fast-that-it-exploded/|website=Astronomy Now|access-date=10 December 2016}} 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 P/2010 A2 (LINEAR)).

References

{{reflist|refs=

{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=331P;cad=1#cad |title=JPL Small-Body Database Browser: (331P/Gibbs) |type=last observation: 2015-12-14}}

}}

External links

[http://skyserver.sdss.org/dr8/en/tools/explore/obj.asp?id=1237666091125310059 331P in SDSS (26 August 2004)]
[http://www.cobs.si/show?id=128 331P confirmation observations, Malina River Observatory (23 March 2012)] {{Webarchive|url=https://web.archive.org/web/20211205155224/https://cobs.si/show?id=128 |date=5 December 2021 }}

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