9 Metis facts for kids
- For the moon of Jupiter, see Metis (moon).
| Discovery | |
|---|---|
| Discovered by | A. Graham |
| Discovery date | April 25, 1848 |
| Designations | |
| 1974 QU2 | |
| Main belt | |
| Orbital characteristics | |
| Epoch July 14, 2004 (JD 2453200.5) | |
| Aphelion | 400.548 Gm (2.678 AU) |
| Perihelion | 313.556 Gm (2.096 AU) |
| 357.052 Gm (2.387 AU) | |
| Eccentricity | 0.122 |
| 1346.815 d (3.69 a) | |
|
Average orbital speed
|
19.21 km/s |
| 274.183° | |
| Inclination | 5.576° |
| 68.982° | |
| 5.489° | |
| Physical characteristics | |
| Dimensions | 235×195×140 km |
| Mass | ~9×1018 kg |
|
Mean density
|
~2.7 g/cm³ |
| ~0.070 m/s² | |
| ~0.11 km/s | |
| 0.2116 d (5.078 h) | |
| Albedo | 0.243 (geometric) |
| Temperature | ~173 K max: 282 K (+9° C) |
|
Spectral type
|
S-type |
| 8.1 to 11.83 | |
| 6.28 | |
| 0.23" to 0.071" | |
9 Metis is one of the biggest main belt asteroids. It is made of silicates and metallic nickel-iron, and may be the core remnant of a big asteroid that was destroyed by an ancient collision.
Discovery and naming
Metis was found by Andrew Graham on April 25, 1848; it was his only asteroid discovery. It is also the only asteroid to have been found as a result of observations from Ireland. Its name comes from the mythological Metis, a Titaness and Oceanid, daughter of Tethys and Oceanus. The name Thetis was also considered and rejected (it would later devolve to 17 Thetis).
Characteristics
Metis' direction of rotation is unknown at present.
Hubble space telescope images and lightcurve analyses are in agreement that Metis has a non-spherical stretched shape with one pointed and one broad end. Radar observations suggest the presence of a significant flat area, in agreement with the shape model from lightcurves.
What the surface is made of has been estimated as 30-40% metal-bearing olivine and 60-70% Ni-Fe metal.
Light curve data on Metis led to an assumption that it could have a moon. However, subsequent observations failed to confirm this. Later searches with the Hubble Space Telescope in 1993 found no moons.
Occultations
Metis has been seen to occult stars no less than 5 times.
— Horizons can be used to obtain a current ephemeris.
Images for kids
-
Lightcurve-based 3D-model of Metis
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See also
In Spanish: (9) Metis para niños
