Mimas (moon)
|
|
| Discovery | |
|---|---|
| Discovered by | William Herschel |
| Discovery date | 17 September 1789 |
| Designations | |
| Pronunciation | /ˈmaɪməs/ or /ˈmiːməs/ |
| Saturn I | |
| Adjectives | Mimantean, Mimantian |
| Orbital characteristics | |
| Periapsis | 181902 km |
| Apoapsis | 189176 km |
| 185539 km | |
| Eccentricity | 0.0196 |
| 0.942 d | |
|
Average orbital speed
|
14.28 km/s (calculated) |
| Inclination | 1.574° (to Saturn's equator) |
| Satellite of | Saturn |
| Physical characteristics | |
| Dimensions | 415.6 × 393.4 × 381.2 km (0.0311 Earths) |
|
Mean radius
|
198.2±0.4 km |
| 490000–500000 km2 | |
| Volume | 32600000±200000 km3 |
| Mass |
(3.7493±0.0031)×1019 kg (6.3×10−6 Earths) |
|
Mean density
|
1.1479±0.007 g/cm3 |
| 0.064 m/s2 (0.00648 g) | |
| 0.159 km/s | |
| synchronous | |
| zero | |
| Albedo | 0.962±0.004 (geometric) |
| Temperature | ≈ 64 K |
| 12.9 | |
Mimas is a moon of Saturn which was discovered in 1789 by William Herschel. It is named after Mimas, a son of Gaia in Greek mythology, and is also designated Saturn I.
With a diameter of 396 kilometres (246 mi) it is the smallest astronomical body that is known to be rounded in shape because of self-gravitation.
Mimas was discovered by the astronomer William Herschel on 17 September 1789. He recorded his discovery as follows: "The great light of my forty-foot [12 m] telescope was so useful that on the 17th of September, 1789, I remarked the seventh satellite, then situated at its greatest western elongation."
Mimas is named after one of the Giants in Greek mythology, Mimas. The names of all seven then-known satellites of Saturn, including Mimas, were suggested by William Herschel's son John in his 1847 publication Results of Astronomical Observations made at the Cape of Good Hope. He named them after Titans specifically because Saturn (the Roman equivalent of Cronus in Greek mythology), was the leader of the Titans and ruler of the world for some time.
The adjectival form of Mimas is Mimantean or Mimantian.
The surface area of Mimas is slightly less than the land area of Spain. The low density of Mimas, 1.15 g/cm3, indicates that it is composed mostly of water ice with only a small amount of rock. Due to the tidal forces acting on it, Mimas is noticeably prolate; its longest axis is about 10% longer than the shortest. The ellipsoidal shape of Mimas is especially noticeable in some recent images from the Cassini probe.
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