11 264 Claudiomaccone: Small binary main-belt asteroid

Photometric CCD observations of the small main-belt asteroid 11 264 Claudiomaccone, carried out with the 0.7-m telescope at Chuguev Observation Station (Kharkiv, Ukraine) in November 2004 and the 1-m telescope at Simeiz Observatory (Crimea, Ukraine) in December 2004, have shown the presence of two different periods in asteroid brightness variations. A short period of 3.1872±0.0006 h and long one of 15.11±0.01 h were determined. The analysis of lightcurves allowed us to suppose that asteroid 11264 Claudiomaccone is an asynchronous binary system in the main belt. The short period is interpreted as a rotational period of the larger (primary) body. The long period component has sharp dips characteristic of mutual eclipse phenomena and is therefore interpreted as the orbital period of the secondary. The parameters of the system are estimated to be: the ratio of the secondary to primary diameters is ⩾0.31, based on the depth of the apparently partial eclipses, the ratio of the orbital radius to the primaryʹs diameter is about 1.5 and a bulk density of the primary body is ρp⩾1.2 g/cm3. We obtained the asteroid phase curve parameters H = 14.30 , G = 0.10 and measured color index V - R = 0.52 . These data allow to suppose that the asteroid belongs to S (or Q) type and to estimate effective diameter of the system to be 4.2 km, based on the average albedo of objects of these taxonomic classes.