221 Eos

221 Eos

Discovery
Discovered by	Johann Palisa
Discovery date	January 18, 1882
Designations
Named after	Eos
Minor planet category	Main belt (Eos)
Orbital characteristics
Epoch 30 January 2005 (JD 2453400.5)
Aphelion	496.912 Gm (3.322 AU)
Perihelion	404.104 Gm (2.701 AU)
Semi-major axis	450.508 Gm (3.011 AU)
Eccentricity	0.103
Orbital period	1908.778 d (5.23 a)
Average orbital speed	17.16 km/s
Mean anomaly	351.618°
Inclination	10.887°
Longitude of ascending node	141.959°
Argument of perihelion	196.03°
Physical characteristics
Dimensions	103.52 ± 5.60[1] km
Mass	(5.87 ± 0.34) × 10^18 kg[1]
Mean density	10.10 ± 1.74[1] g/cm^3
Rotation period	10.436 h
Albedo	0.140
Spectral type	K
Absolute magnitude (H)	7.67

221 Eos /ˈiːɒs/ is a large main-belt asteroid that was discovered by Johann Palisa on January 18, 1882, in Vienna. In 1884, it was named after Eos, the Greek goddess of dawn, to honour the opening of a new observatory that was hoped to bring about a new dawn for Viennese astronomy.^[2]

Based upon its spectral characteristics, this object is classified as a K-type asteroid. The orbital properties show it to be a member of the extensive Eos asteroid family, which is named after it.^[3]

References

1. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
2. Lutz D. Schmadel, Dictionary of Minor Planet Names, p.35
3. Veeder, G. J.; et al. (March 1995), "Eos, Koronis, and Maria family asteroids: Infrared (JHK) photometry", Icarus 114, pp. 186–196, Bibcode:1995Icar..114..186V, doi:10.1006/icar.1995.1053, CiteSeerX: 10.1.1.31.2739, retrieved 2013-04-06.

External links

• The Asteroid Orbital Elements Database
• Minor Planet Discovery Circumstances
• Asteroid Lightcurve Data File
• 221 Eos at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters