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31.7: Selected Moons of the Planets (Appendix G)

  • Page ID
    19719
  • Note: As this book goes to press, nearly two hundred moons are now known in the solar system and more are being discovered on a regular basis. Of the major planets, only Mercury and Venus do not have moons. In addition to moons of the planets, there are many moons of asteroids. In this appendix, we list only the largest and most interesting objects that orbit each planet (including dwarf planets). The number given for each planet is discoveries through 2015. For further information see https://solarsystem.nasa.gov/planets/solarsystem/moons and https://en.wikipedia.org/wiki/List_of_natural_satellites.

    Table \(\PageIndex{1}\): Selected Moons of the Planets
    Planet (moons) Satellite Name Discovery Semimajor Axis (km × 1000) Period (d) Diameter (km) Mass (1020 kg) Density (g/cm3)
    Earth (1) Moon 384 27.32 3476 735 3.3
    Mars (2) Phobos Hall (1877) 9.4 0.32 23 1 × 10−4 2.0
    Deimos Hall (1877) 23.5 1.26 13 2 × 10−5 1.7
    Jupiter (67) Amalthea Barnard (1892) 181 0.50 200
    Thebe Voyager (1979) 222 0.67 90
    Io Galileo (1610) 422 1.77 3630 894 3.6
    Europa Galileo (1610) 671 3.55 3138 480 3.0
    Ganymede Galileo (1610) 1070 7.16 5262 1482 1.9
    Callisto Galileo (1610) 1883 16.69 4800 1077 1.9
    Himalia Perrine (1904) 11,460 251 170
    Saturn (62) Pan Voyager (1985) 133.6 0.58 20 3 × 10−5
    Atlas Voyager (1980) 137.7 0.60 40
    Prometheus Voyager (1980) 139.4 0.61 80
    Pandora Voyager (1980) 141.7 0.63 100
    Janus Dollfus (1966) 151.4 0.69 190
    Epimetheus Fountain, Larson (1980) 151.4 0.69 120
    Mimas Herschel (1789) 186 0.94 394 0.4 1.2
    Enceladus Herschel (1789) 238 1.37 502 0.8 1.2
    Tethys Cassini (1684) 295 1.89 1048 7.5 1.3
    Dione Cassini (1684) 377 2.74 1120 11 1.3
    Rhea Cassini (1672) 527 4.52 1530 25 1.3
    Titan Huygens (1655) 1222 15.95 5150 1346 1.9
    Hyperion Bond, Lassell (1848) 1481 21.3 270
    Iapetus Cassini (1671) 3561 79.3 1435 19 1.2
    Phoebe Pickering (1898) 12,950 550 (R)1 220
    Uranus (27) Puck Voyager (1985) 86.0 0.76 170
    Miranda Kuiper (1948) 130 1.41 485 0.8 1.3
    Ariel Lassell (1851) 191 2.52 1160 13 1.6
    Umbriel Lassell (1851) 266 4.14 1190 13 1.4
    Titania Herschel (1787) 436 8.71 1610 35 1.6
    Oberon Herschel (1787) 583 13.5 1550 29 1.5
    Neptune (14) Despina Voyager (1989) 53 0.33 150
    Galatea Voyager (1989) 62 0.40 150
    Larissa Voyager (1989) 118 1.12 400
    Triton Lassell (1846) 355 5.88 (R)2 2720 220 2.1
    Nereid Kuiper (1949) 5511 360 340
    Pluto (5) Charon Christy (1978) 19.7 6.39 1200 1.7
    Styx Showalter et al (2012) 42 20 20
    Nix Weaver et al (2005) 48 24 46 2.1
    Kerberos Showalter et al (2011) 58 24 28 1.4
    Hydra Weaver et al (2005) 65 38 61 0.8
    Eris (1) Dysnomea Brown et al (2005) 38 16 684
    Makemake (1) (MK2) Parker et al (2016) 160
    Haumea (2) Hi’iaka Brown et al (2005) 50 49 400
    Namaka Brown et al (2005) 39 35 200

    Footnotes

    1R stands for retrograde rotation (backward from the direction that most objects in the solar system revolve and rotate).

    2R stands for retrograde rotation (backward from the direction that most objects in the solar system revolve and rotate).