106 Dione

106 Dione is a large main-belt asteroid. It probably has a composition similar to 1 Ceres. It was discovered by J. C. Watson on October 10, 1868, and named after Dione, a Titaness in Greek mythology who was sometimes said to have been the mother of Aphrodite, the Greek goddess of love and beauty. It is listed as a member of the Hecuba group of asteroids that orbit near the 2:1 mean-motion resonance with Jupiter. The orbital period for this object is 5.66 years and it has an eccentricity of 0.17.

Measurements made with the IRAS observatory give a diameter of 169.92±7.86 km and a geometric albedo of 0.07±0.01. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 168.72±8.89 km and a geometric albedo of 0.07±0.01. Dione was observed to occult a dim star on January 19, 1983, by observers in Denmark, Germany and the Netherlands. A diameter of 147±3 km was deduced, closely matching the value acquired by the IRAS satellite. As of 2012, the mean diameter derived through occultation measurements is 176.7±0.4 km.

Photometric observations of this asteroid collected during 2004–2005 show a rotation period of 16.26±0.02 hours with a brightness variation of 0.08±0.02 magnitude. It is classified as a rare G-type asteroid, suggesting it has a carbonaceous composition with phyllosilicate minerals also being detected.