Ceres lightcurve analysis—Period determination

The sidereal period of Ceres is refined from 9.075 h to 9.074170±0.0000029.074170±0.000002, making use of recent and historical lightcurves spanning almost 50 years. An observed increase in the amplitude of the lightcurve with solar phase angle is consistent with bright, discrete albedo features contributing a greater fraction of light as the defect of illumination increases. Observations near the same phase angle over this time span show no evidence of changes that would indicate active surface processes.