dc.description.abstract | 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 spin-rate limits 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 states was affected by various mechanisms (e.g., mutual collision, tidal force and the Yarkovsky–O’Keefe–Radzievskii–Paddack 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 collaboration with the Purple Mountain Observatory (PMO) to collect asteroid light curves using the CNEOST (Chinese Near-Earth Object Survey Telescope) at Xuyi Observation Station. The main goals of this collaboration are to discover super-fast rotators (SFRs) and to carry out asteroid spin-rate distribution. Two campaigns have been conducted: (a) a survey of ~40 deg2 using 8-min cadence during February 27 – March 2 2017, and (b) a survey of ~50 deg2 using 10-min cadence during March 9 – 12 2018. We obtained 217 reliable rotation periods out of 1650 light curves in the first survey and 332 reliable rotation periods out of 2872 light curves in the second survey.
Almost all asteroids in our samples are the Main-Belt asteroids, and we detect some Hilda asteroids and Jupiter Trojans. In total, we obtained 222 rotation periods of U=3 (i.e. the quality code given by different reliability of light curve) and 327 of U=2, and among them, there are 1 SFR candidates of U=3 and 18 SFR candidates of U=2. Moreover, we found a binary candidate, asteroid (2280) Kunikov, which has a relatively long rotation period listed in the LCDB and is ~6.5 km in diameter. This asteroid shows a light curve with a large amplitude and a sharp similar to the feature of mutual eclipse. To confirm the binarity of (2280) Kunikov, we need more follow-up observations.
We carried out the spin-rate distributions of asteroids of different sizes at different locations in main belt. The result shows that there is no obvious relation between the spin-rate distribution and the size and location of asteroid. | en_US |