21th Largest Asteroid, 45 Eugenia

45 Eugenia is a large main belt asteroid, with a diameter of 215 km. Eugenia is the 21th largest asteroid currently known.

Discovery

Eugenia was discovered on June 27, 1857 by the Franco-German amateur astronomer Hermann Goldschmidt. His instrument of discovery was a 4-inch aperture telescope located in his sixth floor apartment in the Latin Quarter of Paris.

Eugenia was the forty-fifth asteroid to be discovered. The preliminary orbital elements were computed by Wilhelm Forster in Berlin, based on three observations in July, 1857.

Naming

The asteroid was named by its discoverer Hermann Goldschmidt after Empress Eugenia di Montijo, the wife of Napoleon III.

Eugenia was the first asteroid to be definitely named after a real person, rather than a figure from classical legend.

Stats

Diameter (mean): 214.6 km
Aphelion: 2.943 AU
Perihelion: 2.50 AU
Semi-major axis: 2.724 AU
Orbital Period: 4.49 years
Rotation period: 5.699 hrs
Date discovered: 1857.6.27
Class: F
Satellite: 2
Type: Main-belt Asteroid
(data from JPL Small-Body Database)

Physical characteristics

Eugenia is an F-type asteroid, which means that it is very dark in colouring (darker than soot) with a carbonaceous composition.

Eugenia's density appears to be unusually low, indicating that it may be a loosely-packed rubble pile, not a monolithic object. Eugenia appears to be almost anhydrous.

Satellite system

Eugenia is famed as one of the first asteroids to be found to have a moon orbiting it. It is also the second known triple asteroid, after 87 Sylvia.