324P/La Sagra is an active asteroid with an orbital period of 5.44 years. It has been found to be active in more than one perihelia, indicating that the source of activity is sublimation.
Discovery and observation The asteroid was first noticed in images taken by La Sagra Observatory on 14 September 2010 with a 0.45-m f/2.8 reflector by J. Nomen, who also noticed it was diffuse. The asteroid was also found in images obtained in 13 August, but showed no cometary features. On 17 September was noticed that it has a coma with a diameter of 6 arcseconds and a tail 11 arcseconds long.
The comet was recovered on 21 March 2015 by Scott S. Sheppard at Las Campanas Observatory. The object was one magnitude brighter than expected, indicating dust production at a heliocentric distance of , and in May and June a dust tail was observed.
Orbit 324P has an elliptical orbit around the Sun at an average distance of , placing it in the main asteroid belt. With an orbital eccentricity of 0.15, its distance from the Sun ranges from 2.62 AU at perihelion to 3.57 AU at aphelion. It has a high orbital inclination of 21.4° with respect to the ecliptic plane, unusual for a main-belt comet. It is associated with the Alauda family, a roughly 640 million year old asteroid family. Within the Alauda famiy is a small candidate subgroup of 39 asteroids associated with 324P.
Physical characteristics The nucleus of the comet has an effective radius of . The source of activity is water ice sublimation from an area that covers about 0.2% of the surface of the nucleus. The mass loss of the comet is estimated to be 0.2 kg/s, and reached 4.0 kg/s during the 2010 perihelion.
It exhibits non-gravitational acceleration due to outgassing.
Notes
References
External links
at the Minor Planet Center database 324P/La Sagra at Seiichi Yoshida's website 324P/La Sagra at Gideon van Buitenen's website