A Pilot Study of Asteroid Spin Rate Using the CNEOST at Xu-Yi Observatory

摘要

Several important physical properties of asteroid can be derived from light curve, such as rotation sense (e.g. rotation period and spin pole orientation), general shape (e.g., axis ratio estimated form light curve amplitude and shape model from light curve inversion), interior structure (i.e., the 2.2 hr spin-rate limit of rubble-pile asteroids) and taxonomic type (e.g., phase-curve relation). Moreover, the statistics on asteroid spin rate and pole orientation are also important to understand how rotational starus was affected by various mechanisms (e.g., mutual collision, tidal force and the YORP effect). To have a comprehensive study on the aforementioned questions, it relies on a large sample of asteroid rotation. Therefore, we initiated our cross-strait bilateral cooperation with the Purple Mountain Observatory (PMO) to collect asteroid light curves using the CNEOST (Chinese Near-Earth Object Survey Telescope) at Xu-Yi station. A pilot survey of~40 square degrees using 8-min cadence had been carried out during February 27 - March 2 2017. 1650 light curves were collected, from which 79 highly reliable rotation periods were derived. In order to collect more samples, we will continue to carry out more high-cadence observations in next two years.