Photoelectric lightcurves and rotation period of the minor planet 201 Penelope

Results of photoelectric observations of the asteroid 201 Penelope carried out at the European Southern Observatory and Perth Observatory during the 1980 opposition of the asteroid between October 6 and November 7 are presented. Observations were made in the standard UBV and Geneva systems at ESO, and in V-prime at Perth. Examination of composite light curves shows the presence of two distinct maxima and two distinct minima, with a total amplitude of the V light curve of 0.52 magnitudes. A mean synodic rotation period of 3 h, 44 min, 51.6 + or - 7.4 sec is derived. Using a mean phase coefficient beta[SUB]V[/SUB] = 0.037 mag/deg, a primary V (1,0) maximum of 8.51 + or - 0.01 magnitudes is obtained. Color indices are measured as B-V = 0.70 + or - 0.01 and U-B = 0.23 + or - 0.02 magnitudes, and previously reported color variations (Surdej and Cramer, 1980) are attributed to a failure in the reduction procedure.