313 New Asteroid Rotation Periods from Palomar Transient Factory Observations

A new asteroid rotation period survey has been carried out by using the Palomar Transient Factory (PTF). Twelve consecutive PTF fields, which covered an area of 87 deg² in the ecliptic plane, were observed in the R band with a cadence of ~20 minutes during 2013 February 15-18. We detected 2500 known asteroids with a diameter range of 0.5 km <=D <= 200 km. Of these, 313 objects had highly reliable rotation periods and exhibited the "spin barrier" at ~2 hr. In contrast to the flat spin-rate distribution of the asteroids with 3 km <=D <= 15 km shown by Pravec et al., our results deviated somewhat from a Maxwellian distribution and showed a decrease at the spin rate greater than 5 rev day^-1. One superfast rotator candidate and two possible binary asteroids were also found in this work.