This page lists 14 moons with names that start with H, ranging alphabetically from “Halimede” to “Hyrrokkin.” They vary widely in size, from tiny objects just a few kilometers across to Himalia at around 170 km wide. Most orbit the giant planets Jupiter, Saturn, and Neptune, with a few circling smaller worlds like Pluto and the dwarf planet Haumea. These moons help scientists understand how planetary systems formed and how objects in the outer solar system behave over time.

Moons are natural objects that orbit a planet or dwarf planet under the pull of gravity. Humans have known Earth’s Moon for all of recorded history, but moons around other planets were only discovered starting in 1610, when Galileo spotted four of Jupiter’s largest satellites with an early telescope. Today astronomers have confirmed dozens of moons around the solar system’s giant planets, and new ones are still being found.

Below you’ll find the table with the Moon name, Parent Planet, Diameter (km), Discovery Year, and Description.

Moon: The name of each moon that starts with H, listed alphabetically so you can find any specific one quickly.

Parent Planet: The planet or dwarf planet that each moon orbits, helping you see which worlds have the most H-named moons.

Diameter (km): The approximate size of each moon in kilometers, giving you a clear sense of how large or small it is compared to others.

Discovery Year: The year each moon was first confirmed by astronomers, showing you how recent or historic each discovery was.

Description: A brief summary of each moon’s key traits, orbit type, and any notable facts that set it apart from the rest.

Moons

MoonParent PlanetDiameter (km)Discovery Year
HalimedeNeptune622002
HarpalykeJupiter42000
HatiSaturn62000
HegemoneJupiter32003
HelikeJupiter42000
HeleneSaturn321980
HermippeJupiter42001
HerseJupiter22003
Hi’iakaHaumea3202005
HimaliaJupiter1701904
HippocampNeptune342013
HydraPluto512005
HyperionSaturn2701848
HyrrokkinSaturn82004

Descriptions

Halimede
An irregular outer moon of Neptune that orbits in a retrograde direction at a vast distance from the planet. It may be a fragment from a collision with the larger moon Nereid.
Harpalyke
A tiny irregular moon of Jupiter belonging to the Ananke group, likely a remnant from a captured body that broke apart long ago. It orbits Jupiter in a retrograde direction.
Hati
A small irregular moon of Saturn in the Norse group, orbiting in a retrograde direction at a great distance. It is named after a wolf from Norse mythology said to chase the Moon.
Hegemone
One of Jupiter’s smallest known moons, belonging to the Pasiphae group and orbiting far from the planet in a retrograde path. Named after a Greek goddess of plants and seasons.
Helike
A small irregular moon of Jupiter in the Ananke group, named after a nymph from Greek mythology. It travels in a retrograde orbit far beyond Jupiter’s main ring system.
Helene
A small moon of Saturn that shares its orbit with the larger moon Dione as a Trojan companion, leading Dione by 60 degrees. Its dusty, irregular surface shows unusual ridge features.
Hermippe
A tiny irregular moon of Jupiter in the Ananke group, named after a figure in Greek mythology. Like its group siblings, it orbits Jupiter in a distant retrograde path.
Herse
One of Jupiter’s smallest confirmed moons, belonging to the Carme group and orbiting in a retrograde direction. It is named after a daughter of Zeus and Selene in Greek myth.
Hi’iaka
The larger of dwarf planet Haumea’s two known moons, named after the Hawaiian goddess of healing and dance. It completes an orbit around Haumea roughly every 49 days.
Himalia
Jupiter’s largest irregular moon and the fifth largest overall, discovered using photographic plates at Lick Observatory. It leads a group of irregular moons that share a similar orbit.
Hippocamp
A tiny inner moon of Neptune discovered in archival Hubble Space Telescope images, orbiting very close to the much larger moon Proteus. It may have broken off from Proteus long ago.
Hydra
One of Pluto’s small outer moons, found by the Hubble Space Telescope. NASA’s New Horizons flyby in 2015 revealed its elongated, irregular shape and surprisingly bright, icy surface.
Hyperion
Saturn’s largest irregularly shaped moon, famous for its sponge-like surface covered in deep pits and unusual dark deposits. It tumbles chaotically in its orbit rather than rotating steadily.
Hyrrokkin
A small irregular moon of Saturn in the Norse group, named after a giantess from Norse mythology renowned for her enormous strength. It follows a distant retrograde orbit around Saturn.
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