9 Metis
| Discovery | |
|---|---|
| Discovered by | A. Graham |
| Discovery date | 25 April 1848 |
| Designations | |
| (9) Metis | |
| Pronunciation | /ˈmiːtɪs/ |
Named after | Mētis |
| 1974 QU2 | |
| Main belt | |
| Adjectives | Metidian /mɛˈtɪdiən/ |
| Symbol | (historical) |
| Orbital characteristics | |
| Epoch 13 September 2023 (JD 2453300.5) | |
| Aphelion | 2.68 AU (401 million km) |
| Perihelion | 2.093 AU (313.1 million km) |
| 2.387 AU (357.1 million km) | |
| Eccentricity | 0.1231 |
| 3.69 yr (1346.74 d) | |
| 345.43° | |
| Inclination | 5.577° |
| 68.87° | |
| 6 November 2023 | |
| 5.75° | |
| Earth MOID | 1.1 AU (160 million km) |
| Proper orbital elements | |
Proper semi-major axis | 2.3864354 AU |
Proper eccentricity | 0.1271833 |
Proper inclination | 4.6853629° |
Proper mean motion | 97.638314 deg / yr |
Proper orbital period | 3.68708 yr (1346.705 d) |
Precession of perihelion | 38.754973 arcsec / yr |
Precession of the ascending node | −41.998090 arcsec / yr |
| Physical characteristics | |
| Dimensions | (222 × 182 × 130) ± 12 km |
| 173±2 km 190±? km (Dunham) | |
| Flattening | 0.39 |
| Mass | (8.0±1.9)×1018 kg (11.3±2.2)×1018 kg |
Mean density | 2.94±0.70 g/cm3 4.12±1.17 g/cm3 |
| 0.2116 d (5.079 h) | |
| 0.18 0.118 | |
| Temperature | max: 282 K (+9 °C) |
| S | |
| 8.1 to 11.83 | |
| 6.33 | |
| 0.23" to 0.071" | |
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9 Metis is one of the larger main-belt asteroids. It is composed of silicates and metallic nickel-iron, and may be the core remnant of a large asteroid that was destroyed by an ancient collision. Metis is estimated to contain just under half a percent of the total mass of the asteroid belt.