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Eos family





A family of asteroids, first detected by the Japanese astronomer Kiyotsugu Hirayama (1874-1943) in 1918, that moves in the outer asteroid belt at a mean distance of 3.02 AU from the Sun. Most Eos asteroids appear to belong class C (carbonaceous) or S (silicaceous); spectral studies have linked some Eos family members specifically with carbonaceous chondrites of the CO and CV type, while others have yet to be matched with known meteorite counterparts. This compositional variation suggests that the Eos parent body was partially differentiated. The family is named after (221) Eos, discovered on Jan. 18, 1882 by Johann Palisa.


Data for (221) Eos
diameter 112 km
class S
semimajor axis 3.014 AU
perihelion 2.72 AU
aphelion 3.31 AU
eccentricity 0.077
inclination 10.9°
period 5.23 years


Related category

   • ASTEROIDS AND OTHER MINOR PLANETS: TYPES AND GROUPS