283 Emma

283 Emma is a large asteroid of the asteroid belt and the namesake of the Emma family. It was discovered by Auguste Charlois on 8 February 1889, in Nice, France. The reason for its name is unknown.
Measurements made with the IRAS observatory give a diameter of and a geometric albedo of. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of and a geometric albedo of. When the asteroid was observed occulting a star, the results showed a diameter of.

Satellite

A companion for 283 Emma was detected on 14 July 2003 by W. J. Merline et al. using the Keck II telescope and is designated S/2003 1. The discovery was reported in the International Astronomical Union Circular 8165. The satellite orbits at a semi-major axis of about 581 km with an eccentricity of 0.12. Emma has a Hill sphere with a radius of about 28,000 km.