| while having a comet - like appearance , ( gibbs ) has an orbit native to the main asteroid belt , and physically is a km - sized asteroid which recently ( mid 2011 ) experienced an impulsive mass ejection event . here we report new observations of this object obtained with the keck ii telescope on ut 2014 august 26 . the data show previously undetected scale fragments of the main nucleus , and reveal a rapid nucleus spin with a rotation period of @xmath0 hr . the existence of large fragments and the fast nucleus spin are both consistent with rotational instability and partial disruption of the object . to date , many fast rotators have been identified among the minor bodies , which , however , do not eject detectable fragments at the present - day epoch , and also fragmentation events have been observed , but with no rotation period measured . is unique in that for the first time we detected fragments and quantified the rotation rate of one and the same object . the rapid spin rate of is very close to the spin rates of two other active asteroids in the main belt , 133p / elst - pizarro and ( 62412 ) , confirming the existence of a population of fast rotators among these objects . but while shows impulsive ejection of dust and fragments , the mass loss from 133p is prolonged and recurrent . we believe that these two types of activity observed in the rapidly rotating active asteroids have a common origin in the rotational instability of the nucleus . |