(9) Metis
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Asteroid (9) Metis 
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| Properties of the orbit ( animation ) | |
| Orbit type | Main belt asteroid |
| Major semi-axis | 2.386 AU |
| eccentricity | 0.122 |
| Perihelion - aphelion | 2.094 AU - 2.678 AU |
| Inclination of the orbit plane | 5.6 ° |
| Length of the ascending node | 68.9 ° |
| Argument of the periapsis | 6.3 ° |
| Time of passage of the perihelion | February 9, 2009 |
| Sidereal period of rotation | 3 a 250 d |
| Mean orbital velocity | 19.21 km / s |
| Physical Properties | |
| Medium diameter | 190 km |
| Dimensions | ≈ 9 · 10 18 kg |
| Albedo | 0.12 |
| Medium density | ≈ 2.7 g / cm³ |
| Rotation period | 5.1 h |
| Absolute brightness | 6.3 mag |
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Spectral class (according to Tholen) |
S. |
| history | |
| Explorer | Andrew Graham |
| Date of discovery | April 25, 1848 |
| 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. | |
(9) Metis is an asteroid of the main asteroid belt discovered on April 25, 1848 by Andrew Graham at the Markree Observatory as the ninth asteroid. The name refers to the Greek goddess Metis , the mother of Pallas Athene .
Metis moves at a distance of 2.1 ( perihelion ) to 2.7 ( aphelion ) astronomical units , in 3.7 years on an eccentric orbit around the sun . The orbit is inclined 5.6 ° to the ecliptic , the orbit eccentricity is 0.22.
Metis has a diameter of 190 km. It rotates around its own axis in around 5 hours. The albedo is 0.12. During opposition , Metis attains a brightness of 9.1 mag , making it one of the brightest asteroids in the night sky. To find them, however, you need a telescope or bright prism binoculars .
Evaluations of the light curves from Metis gave rise to the assumption that the asteroid is accompanied by a natural satellite. However, this has not yet been confirmed.
In 1993 Metis was observed with the help of the Hubble telescope . It turned out that the asteroid has an irregular shape. Satellites were not found.
