(221) Eos
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Asteroid (221) Eos |
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| Properties of the orbit ( animation ) | |
| Orbit type | Outer main belt |
| Asteroid family | Eos family |
| Major semi-axis | 3.009 AU |
| eccentricity | 0.105 |
| Perihelion - aphelion | 2,695 AU - 3,324 AU |
| Inclination of the orbit plane | 10.9 ° |
| Length of the ascending node | 141.8 ° |
| Argument of the periapsis | 193.4 ° |
| Sidereal period | 5.22 a |
| Mean orbital velocity | 17.16 km / s |
| Physical Properties | |
| Medium diameter | 95.469 (± 1.684) km |
| Albedo | 0.166 (± 0.013) |
| Rotation period | 10.443 h |
| Absolute brightness | 7.67 likes |
| Spectral class | S. |
| history | |
| Explorer | Johann Palisa |
| Date of discovery | January 18, 1882 |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items. | |
(221) Eos is an asteroid of the outer main asteroid belt , which was discovered on January 18, 1882 by Johann Palisa at the University Observatory in Vienna .
The celestial body was named after Eos , the goddess of the dawn from Greek mythology .
Eos moves around the Sun at a distance of 2.70 ( perihelion ) to 3.32 ( aphelion ) astronomical units in 5 years and 81 days . The orbit is inclined 10.9 ° to the ecliptic , the orbital eccentricity is 0.105.
Eos is 95.5 kilometers in diameter and has a relatively light, silicate-rich surface with an albedo of 0.166. The planetoid rotates around its own axis in around 10 hours and 26 minutes.
Eos family
The asteroid is the namesake of the Eos family . This is one of the first three asteroid groups described by the Japanese astronomer Kiyotsugu Hirayama in 1918, and with around 4400 asteroids is one of the largest. This group of asteroids typically has large semiaxes from 2.95 to 3.1 AU , orbital inclinations between 8 ° and 12 ° and is limited inwardly by the Kirkwood gap of the 7: 3 resonance with Jupiter . It is believed that the family was created by a collision about 1.1 billion years ago.
See also
Web links
- Asteroid Eos: Discovery Circumstances according to the Minor Planet Center of the International Astronomical Union at the Harvard-Smithsonian Center for Astrophysics, Cambridge, USA
- (221) Eos in the Small-Body Database of the Jet Propulsion Laboratory .
- (221) Eos in the database of the "Asteroids - Dynamic Site" (AstDyS-2, English).
Individual evidence
- ↑ JPL: 221 Eos. In: NASA . Retrieved July 14, 2017 (English).
- ↑ Yoshihide Kozai: Kiyotsugu Hirayama and His Families of Asteroids. In: The SAO / NASA Astrophysics Data System. 1993, accessed July 14, 2017 .
- ↑ a b David Vokrouhlický , Miroslav Brož , Alessandro Morbidelli , William Bottke , David Nesvorny , Daniel Lazzaro , Andy Rivkin : Yarkovsky footprints in the Eos family. (PDF) 2006, accessed on July 14, 2017 (English).