CCD Photometry of Asteroids 168, 206 and 506

Abstract

A quantity of C-type asteroids with intermediate size has been selected as the targets of our observational program in Yunnan Observatory, China since 2000. In this paper, we report the results of the photometric observation for three of them, 168 Sibylla, 206 Hersilia and 506 Marion during 2002–2003. The synodic period of 9.100±0.009 h of 206 is different from the value given by Harris (2003). The synodic periods of 168 and 506 we estimated are 24.41±0.01 h, and 13.51±0.01 h, respectively, which are slightly different from the values given by Harris (2003). Their composed lightcurves using new periods are presented.