Mimas

Mimas
Mimas imaged by the Cassini orbiter, February 2010. Mimas's surface is dominated by craters; the large crater at the right is Herschel
Discovery
Discovered byWilliam Herschel
Discovery date17 September 1789[1]
Designations
Designation
Saturn I
Pronunciation/ˈmməs/[2] or as Greco-Latin Mimas (approximated /ˈmməs/)
Named after
Μίμας Mimās
AdjectivesMimantean,[3] Mimantian[4] (both /mɪˈmæntiən/)
Orbital characteristics[5]
Periapsis181902 km
Apoapsis189176 km
185539 km
Eccentricity0.0196
0.942421959 d
14.28 km/s (calculated)
Inclination1.574° (to Saturn's equator)
Satellite ofSaturn
Physical characteristics
Dimensions415.6 × 393.4 × 381.2 km
(0.0311 Earths)[6]
198.2±0.4 km[6][7]
490000500000 km2
Volume32600000±200000 km3
Mass(3.75094±0.00023)×1019 kg[7]
(6.3×10−6 Earths)
Mean density
1.1501±0.0070 g/cm3[7]
0.064 m/s2 (0.00648 g)
0.159 km/s
synchronous
zero
Albedo0.962±0.004 (geometric)[8]
Temperature≈ 64 K
12.9 [9]

Mimas, also designated Saturn I, is the seventh-largest natural satellite of Saturn. With a mean diameter of 396.4 kilometres or 246.3 miles, Mimas is the smallest astronomical body known to be roughly rounded in shape due to its own gravity. Mimas's low density, 1.15 g/cm3, indicates that it is composed mostly of water ice with only a small amount of rock, and study of Mimas's motion suggests that it may have a liquid ocean beneath its surface ice. The surface of Mimas is heavily cratered and shows little signs of recent geological activity. A notable feature of Mimas's surface is Herschel, one of the largest craters relative to the size of the parent body in the Solar System. Herschel measures 139 kilometres (86 miles) across, about one-third of Mimas's mean diameter,[10] and formed from an extremely energetic impact event. The crater's name is derived from the discoverer of Mimas, William Herschel, in 1789. The moon's presence has created one of the largest 'gaps' in Saturn's ring, named the Cassini Division, due to orbital resonance destabilising the particles' orbit there.

  1. ^ Cite error: The named reference CosmoVisions was invoked but never defined (see the help page).
  2. ^ "Mimas". Merriam-Webster.com Dictionary. Merriam-Webster.
  3. ^ "JPL (2009) Cassini Equinox Mission: Mimas". Archived from the original on 6 April 2009. Retrieved 6 April 2009.
  4. ^ Harrison (1908) Prolegomena to the study of Greek religion, ed. 2, p. 514
  5. ^ Cite error: The named reference Harvey-2007 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Roatsch-2009 was invoked but never defined (see the help page).
  7. ^ a b c Jacobson, Robert. A. (1 November 2022). "The Orbits of the Main Saturnian Satellites, the Saturnian System Gravity Field, and the Orientation of Saturn's Pole*". The Astronomical Journal. 164 (5): 199. Bibcode:2022AJ....164..199J. doi:10.3847/1538-3881/ac90c9. S2CID 252992162.
  8. ^ Cite error: The named reference Verbiscer-2007 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference ARVAL-2007 was invoked but never defined (see the help page).
  10. ^ "Herschel". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.