Analysis of the asteroids' photometric observations

In this study, four bright main-belt asteroids which have relatively short rotation period were selected and observed photometrically to redetermine the lightcurve shapes, sidereal rotation periods and pole directions by using the convex inversion method described in Kaasalainen & Torppa (2001) and Kaasalainen et al. (2001).Actually, the lightcurve shapes and the spin state models of these four selected asteroids (201Penelope, 511Davida, 694Ekard, 776Berbericia) were known in the literature; however, the large photometric data spanned over a long period of time is always needed to obtain reliable parameters. Our limited photometric data were taken into account together with those in the literature to perform the first sample convex inversion application in Turkey.New observations of these four asteroids were carried out at Canakkale Onsekiz Mart University Astrophysics Research Center & Ulupinar Observatory. Some observations of 201Penelope were performed at TUBITAK National Observatory of Turkey (TUG).In analyses, the code developed by Mikko Kaasalainen in Fortran and later converted to C by Josef Durech and MPO LCInvert described in Warner (2007), a Windows-based program which is based on the original code, were used. The consistent solutions were found with those in the literature and model lightcurves were fitted to new lightcurves by means of the convex inversion method.Keywords: Asteroids, photometry, rotation, shape, convex inversion