13 Egeria
From Wikipedia, the free encyclopedia
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Discovery
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| Discovered by | Annibale de Gasparis |
| Discovery date | November 2, 1850 |
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Designations
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| Alternative names | none |
| Minor planet category |
Main belt |
| Epoch July 14, 2004 (JD 2453200.5) | |
| Aphelion | 417.953 Gm (2.794 AU) |
| Perihelion | 352.719 Gm (2.358 AU) |
| Semi-major axis | 385.336 Gm (2.576 AU) |
| Eccentricity | 0.085 |
| Orbital period | 1509.977 d (4.13 a) |
| Average orbital speed | 18.56 km/s |
| Mean anomaly | 339.787° |
| Inclination | 16.540° |
| Longitude of ascending node | 43.305° |
| Argument of perihelion | 81.401° |
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Physical characteristics
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| Dimensions | 207.6 km (217×196 km) |
| Mass | ~9.4×1018 kg |
| Mean density | 2 ? g/cm³ |
| Equatorial surface gravity | ~0.0580 m/s² |
| Escape velocity | ~0.1098 km/s |
| Rotation period | 0.2935 d[1] |
| Albedo | 0.083[2] |
| Temperature | ~174 K |
| Spectral type | G-type asteroid |
| Absolute magnitude | 6.74 |
13 Egeria (pronounced /ɪˈdʒɪəriə/, Latin: Æge?ria) is a large Main belt G-type asteroid.[3]
It was discovered by A. de Gasparis on November 2, 1850, and was named by Urbain J. J. Le Verrier, whose computations led to the discovery of Neptune. Egeria was a goddess (other sources say a nymph) of Aricia, in Italy, and the wife of Numa Pompilius, second king of Rome.
Egeria occulted a star on January 8, 1992. The former's disc was determined to be quite circular (217×196 km).
[edit] References
- ^ [1][dead link]
- ^ [2][dead link]
- ^ Rivkin, A. S.; J. K. Davies, S. L. Ellison, L. A. Lebofsky. HIGH-RESOLUTION 2.5–3.5 �M OBSERVATIONS OF C-, B- AND G-CLASS ASTEROIDS. (English). Retrieved on 2008-04-20.
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