878 Mildred is an asteroid orbiting the Sun in the main asteroid belt. It has been proposed to host an asteroid family called the Mildred family, which is thought to belong in the Nysa–Polana complex. The Mildred subgroup, and by extension 878 Mildred itself, is thought to have been formed by a recent fragmentation event from a larger asteroid.
Discovery 878 Mildred was originally discovered in 1916 using the 1.5 m Hale Telescope at the Mount Wilson Observatory, but was subsequently lost until it was again observed on single nights in 1985 and 1991 (a lost asteroid). Initially only two observations of the asteroid were taken on 1916-09-06 which does not allow for an accurate orbital determination, however interest in the object prompted further investigation and more measurements were taken in late September and October. The asteroid was re-discovered in 1991 by Gareth V. Williams. It is named after Mildred Shapley Matthews.
Physical properties By comparing the asteroid's perceived brightness and the then computed distance from the Sun the discoverers arrived at an absolute visual magnitude of 14.3, which if one assumes Mars-like albedo gives an approximate diameter of 3 to 5 kilometers.
References
External links Minor Planet Center Database entry on (878) Mildred 878 Mildred at AstDyS-2, Asteroids—Dynamic Site Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info 878 Mildred at the JPL Small-Body Database