Naming of natural satellites

Historically the naming of natural satellites did not always match the times of their discovery:

• The moons of Mars were named by their discoverer in 1878 soon after their discovery in 1877.

• The Galilean moons of Jupiter (Io, Europa, Ganymede and Callisto) were named by Simon Marius soon after their discovery in 1610. However, by the late 19th century these names had fallen out of favor, and for a long time (until the mid 20th century) it was most common to refer to them in the astronomical literature simply as "Jupiter I", "Jupiter II", "Jupiter III" and "Jupiter IV", or as "the first satellite of Jupiter", "Jupiter's second satellite", etc.

• The moons of Jupiter discovered between 1904 and 1951 were not named until 1975, being known until then simply by their Roman numeral designations (Jupiter VI through Jupiter XII). The moon Amalthea (Jupiter V), discovered in 1892, was unofficially named but its name was also not made official until 1975. Most likely Charles Kowal's discovery of Leda (Jupiter XIII) in 1974 finally prompted the IAU to act. Since the names of the Galilean satellites themselves had fallen out of favor, it is perhaps not unusual that the discoverers of the new smaller satellites did not see fit to name them either.

• The seven known moons (at the time) of Saturn were named in 1847 by John Herschel. Until then, Titan was known as the "Huygenian (or Huyghenian) satellite of Saturn". Hyperion was discovered soon after in 1848 and also named in accordance with Herschel's naming scheme, and the eight moons had Roman numeral designations in order of their distance from Saturn. The ninth moon Phoebe was named by its discoverer in 1899 soon after its discovery.

• The four known moons (at the time) of Uranus were named in 1852 by John Herschel, not long after the discovery of the later two in 1851. Later, the fifth known moon Miranda was named by its discoverer in 1949 soon after its discovery.

• The one known moon (at the time) of Neptune was not named for many decades. Although the name Triton was suggested in 1880, it did not come into general use until the mid 20th-century. In the astronomical literature it was simply referred to as "the satellite of Neptune". Later, the second known moon Nereid was named by its discoverer in 1949 soon after its discovery.

The names of all subsequently discovered satellites were officially approved by the IAU's committee for Planetary System Nomenclature, which was formed in 1973 and is today known as the Working Group for Planetary System Nomenclature (WGPSN). In some cases, names such as Janus and Leda and Charon were suggested by their discoverers.

See also

• Timeline of natural satellites

• Jupiter's natural satellites
• Saturn's natural satellites
• Uranus's natural satellites
• Neptune's natural satellites

References

• John Herschel names the seven known satellites of Saturn: MNRAS 8 (1848) 42 in his 1847 publication of Results of Astronomical Observations made at the Cape of Good Hope)
• John Herschel names the four known satellites of Uranus: AN, 34 (1852) 325/326 in 1852
• Asaph Hall names his two newly-discovered satellites of Mars: AN, 92 (1878) 47/48 in 1878.
• Seth Barnes Nicholson declines to name satellites of Jupiter he has discovered: PASP 51 (1939) 93

• IAUC 2846: Names for some satellites of Jupiter
• IAUC 3872: Names for some satellites of Jupiter and Saturn
• IAUC 4157: Names for some satellites of Saturn and satellite of Pluto
• IAUC 4609: Names for some satellites of Saturn and Uranus
• IAUC 5347: Names for some satellites of Saturn and Neptune
• IAUC 7479: Names for some satellites of Uranus
• IAUC 7998: Names for some satellites of Jupiter (error for Megaclite) correction
• IAUC 8177: Names for some satellites of Jupiter, Saturn, Uranus (later changed for Skathi, Suttungr, Thrymr)

• Astronomical Headlines
• Astronomical headlines (old)

• Gazetteer of Planetary Nomenclature