There are 288 discovered natural satellites – or moons, as they are colloquially known – in the Solar system. Most of these are found in the outer gas giants. However, many of these have not received proper names as they were discovered recently and have yet to be confirmed. Only 164 moons have proper names.
Out of those, there are 12 moons whose names start with the letter H. These are all listed in the following table. Below you will also find some additional details about each, including physical characteristics, the original meaning of their names, etc.
| Moon Name | Planet | Name Meaning |
|---|---|---|
| Halimede | Neptune | One of the Nereids in Greek mythology |
| Harpalyke | Jupiter | Princess of Arcadia |
| Hati | Saturn | Giant wolf from Norse mythology. Son of Fenrir |
| Hegemone | Jupiter | One of the Graces or Charities (goddesses of charm, beauty, goodwill, and creativity) |
| Helene | Saturn | Named after Helen of Troy. Granddaughter of Cronus |
| Helike | Jupiter | One of the nymphs |
| Hermippe | Jupiter | Daughter of Boetus. Had a son with Poseidon |
| Herse | Jupiter | Personification of dew. Daughter of Zeus and the Moon (Selene). Also known as Ersa |
| Himalia | Jupiter | Nymph of the island of Rhodes. Had three sons with Zeus: Sparteus, Kronios and Kytos |
| Hippocamp | Neptune | Named after the mythological sea-horse creature |
| Hyperion | Saturn | Titan god of observation. Father of Helios, Eos, and Selene (the Moon) |
| Hyrrokkin | Saturn | A female Jötunn (giant) |
Halimede
Discovered in 2002 by Matthew J. Holman and his team, Halimede is one of Neptune’s irregular satellites. Named after one of the fifty Nereids (sea nymphs) in Greek mythology, it is approximately 62 kilometers in diameter. The moon follows a highly inclined, eccentric orbit at an average distance of 16.6 million kilometers from Neptune. Its gray coloration and orbital characteristics suggest it may be a captured object from the Kuiper Belt.
Harpalyke
Discovered in 2000 by Scott S. Sheppard and his team, Harpalyke is one of Jupiter’s irregular satellites. Named after the tragic princess of Arcadia in Greek mythology, this small moon is approximately 4 kilometers in diameter. It orbits Jupiter at an average distance of 21.1 million kilometers in a retrograde direction. It is a member of the Ananke group, suggesting it originated from a single parent body that broke apart.
Hati
Discovered in 2004 by Scott S. Sheppard and his team, Hati is one of Saturn’s irregular satellites. Named after the giant wolf from Norse mythology who chases the moon across the sky and is the son of Fenrir, this small moon is approximately 6 kilometers in diameter. It follows a retrograde orbit at an average distance of 20.3 million kilometers from Saturn, characteristic of captured irregular satellites.
Hegemone
Discovered in 2003 by Scott S. Sheppard’s team, Hegemone is one of Jupiter’s irregular satellites. Named after one of the Graces (Charities) in Greek mythology who personified charm and beauty, this moon is approximately 3 kilometers in diameter. It orbits Jupiter at an average distance of 23.7 million kilometers in a retrograde direction, suggesting it was captured rather than formed alongside Jupiter.
Helene
Discovered in 1980 by Pierre Laques and Jean Lecacheux at Pic du Midi Observatory, Helene is one of Saturn’s trojan moons, sharing an orbit with the larger moon Dione. Named after Helen of Troy from Greek mythology, it measures about 35 kilometers across. Helene orbits at approximately 377,400 kilometers from Saturn, following Dione in its orbit at the L4 Lagrange point. Its surface is heavily cratered and covered with unusually smooth material, giving it a distinctive appearance.
Helike
Discovered in 2003 by Scott S. Sheppard’s team, Helike is one of Jupiter’s irregular satellites. Named after one of Zeus’s many nymph lovers in Greek mythology, this small moon is approximately 4 kilometers in diameter. It orbits Jupiter at an average distance of 21.2 million kilometers. Like many of Jupiter’s irregular satellites, it is believed to be a captured asteroid.
Hermippe
Discovered in 2001 by Scott S. Sheppard and his team, Hermippe is one of Jupiter’s irregular satellites. Named after the daughter of Boetus who bore a son to Poseidon in Greek mythology, this moon is approximately 4 kilometers in diameter. It orbits Jupiter at an average distance of 21.3 million kilometers in a retrograde direction, as part of the Ananke group.
Herse
Discovered in 2003 by Brett J. Gladman and his team, Herse is one of Jupiter’s irregular satellites. Named after the personification of dew in Greek mythology (also known as Ersa), this small moon is approximately 2 kilometers in diameter. It orbits Jupiter at an average distance of 23.2 million kilometers. Its highly inclined orbit suggests it was captured by Jupiter’s gravity rather than forming in place.
Himalia
Discovered in 1904 by Charles Dillon Perrine at Lick Observatory, Himalia is Jupiter’s largest irregular satellite with a diameter of about 140 kilometers. Named after the nymph of Rhodes who bore three sons to Zeus in Greek mythology, it is the largest member of the Himalia group of moons. It orbits Jupiter at an average distance of 11.5 million kilometers and has a distinctly reddish color, suggesting a possible asteroidal origin.
Hippocamp
Discovered in 2013 by Mark Showalter using Hubble Space Telescope images, Hippocamp is Neptune’s smallest known inner moon, measuring only about 35 kilometers across. Named after the mythological sea-horse creatures that pulled Poseidon’s chariot, it orbits very close to Neptune at about 105,000 kilometers from the planet’s center. Scientists believe it may be a fragment broken off from the larger moon Proteus during a comet impact billions of years ago.
Hyperion
Discovered in 1848 by William Cranch Bond, George Phillips Bond, and William Lassell, Hyperion is one of Saturn’s larger irregular moons, measuring about 270 kilometers across. Named after the Titan god of observation in Greek mythology, it has a distinctive sponge-like appearance due to its unusually low density and high porosity. It exhibits chaotic rotation, meaning its axis of rotation wobbles so much that its orientation in space is unpredictable. Hyperion orbits Saturn at an average distance of 1.48 million kilometers and is in orbital resonance with Titan.
Hyrrokkin
Discovered in 2004 by Scott S. Sheppard and his team, Hyrrokkin is one of Saturn’s irregular satellites. Named after a giantess in Norse mythology who was strong enough to launch Baldr’s funeral ship that no other god could move, this small moon is approximately 6 kilometers in diameter. It follows a retrograde orbit at an average distance of 18.2 million kilometers from Saturn, suggesting it was captured rather than formed alongside the planet.
Click on a letter below for a list of moons that begin with it.
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
Related:
For more on how moons are named check out this article.