Chan-Kao Chang (IANCU); Hsing-Wen Lin (Univ. of Michigan); Ting-Shuo Yeh (IANUC); Wing-Huen Ip (IANCU); the PTF Team
Super-fast rotators (SFRs) are a special group of asteroid, which is against the current understanding of asteroid interior structure (i.e., the rubble-pile structure; gravitationally bounded aggregations). Therefore, any physical properties sheared by SFRs is important to understand their formation and also to the entire asteroid system. One of the fundamental quantities is the population size of SFRs, which can tell the probability to form a SFR. In order to constrain their population of SFRs, we conducted several high-cadence survey on asteroid rotation periods using the PTF. The preliminary result shows the SFRs could be very rare comparing to the average asteroids. This suggests that SFRs could have a special formation history other than the rest of asteroids.