(13) Egeria
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Asteroid (13) Egeria 
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| Properties of the orbit ( animation ) | |
| Orbit type | Main belt asteroid |
| Major semi-axis | 2.575 AU |
| eccentricity | 0.086 |
| Perihelion - aphelion | 2.354 AU - 2.796 AU |
| Inclination of the orbit plane | 16.5 ° |
| Length of the ascending node | 43.27711 ± 0.00002 ° |
| Argument of the periapsis | 80.46368 ± 0.00005 ° |
| Time of passage of the perihelion | November 21, 2008 |
| Sidereal period | 4 a 48 d |
| Mean orbital velocity | 18.5 km / s |
| Physical Properties | |
| Medium diameter | 217 × 196 km |
| Dimensions | 9.4 x 10 18 kg |
| Albedo | geometric albedo: 0.083 ± 0.007 radar albedo: 0.059 ± 0.023 |
| Medium density | approx. 2 g / cm³ |
| Rotation period | 7 h 3 min |
| Absolute brightness | 6.7 likes |
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Spectral class (according to Tholen) |
G |
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Spectral class (according to SMASSII) |
Ch |
| history | |
| Explorer | Annibale De Gasparis |
| Date of discovery | November 2, 1850 |
| 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. | |
(13) Egeria is an asteroid of the main asteroid belt discovered by Annibale De Gasparis as the thirteenth asteroid on November 2, 1850 .
The heavenly body was named after Egeria , a prophetic spring nymph in Roman mythology .
description
Egeria moves at a distance of about 2.4 ( perihelion ) to about 2.8 ( aphelion ) astronomical units , in 4.1 years around the sun . The orbit is strongly inclined towards the ecliptic at about 16.5 ° , the orbit eccentricity is about 0.086.
With a mean diameter of around 200 kilometers, Egeria is one of the largest asteroids in the main belt. It has a dark carbonaceous surface with a geometric albedo of about 0.08. It rotates around its own axis in 7 hours and 3 minutes.
On January 8, 1992 was occultation Egeria observed. By evaluating the light curve , it was possible to determine the extent of the asteroid to 217 × 196 km.
Spectral analyzes have shown that Egeria consists of 10.5–11.5% water ice.
See also
Individual evidence
- ↑ Christopher Magri, Michael C. Nolan, Steven J. Ostroc, Jon D. Giorgini: A radar survey of main-belt asteroids: Arecibo observations of 55 objects during 1999-2003 . In: Icarus . Number 186, 2007, p. 137, DOI: 10.1016 / j.icarus.2006.08.018 .
- ↑ http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1414.pdf