A Photometric Survey of over 200 V-type Asteroids and Their Phase-curve Analysis

Abstract V-type asteroids are considered to be crustal fragments of asteroid (4) Vesta and possibly of other differentiated parent bodies that once existed in the main asteroid belt. A dedicated photometric survey of 213 V-type asteroids and V-type candidates is presented, based on unfiltered CCD observations roughly calibrated with stars from the Carlsberg Meridian Catalogue. The rotation properties and phase-curve slope parameters ( G ) were derived for most of the targets. Additional phase-curve parameters ( G 12 , G 1 , and G 2 ) were determined for selected apparitions, and approximate empirical relationships between G and the indexed phase-curve parameters were established. The median and mean values of these parameters, together with the standard deviations, can provide practical approximations for V-type asteroids with poorly determined parameters. Contamination of the sample by a few asteroids of a different taxonomic type is not ruled out, but is expected to have a negligible effect on the result. A comparison between V-types within the Vesta family and the overall sample indicates subtle but systematic differences in phase-curve parameters. A weak correlation between phase-curve parameters and orbital distance from (4) Vesta is tentatively found within the family. As the internal magnitude level is close to the Cousins R band, absolute magnitudes H R can be estimated for the entire dataset, with a typical uncertainty of approximately 0.2 mag, especially for their mean values from multiple apparitions.