Space · Moons

Himalia

A moon of Jupiter — The largest of Jupiter's outer irregular moons — discovered photographically a year after the technique was first applied to moon-hunting.

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Quick facts

Parent planet

Jupiter

Diameter (mean)

139 km

Mass

6.7 × 10¹⁸ kg
9.11e-05 Moon masses

Mean orbital radius

11,460,000 km

Orbital period

250.6 Earth days

Discovery year

1904

Discoverer

Charles Dillon Perrine

Naming origin

Greek nymph, mother of three sons by Zeus

Surface conditions

Himalia is the largest of Jupiter's outer irregular satellites, orbiting at 11.5 million km — more than 25 times the orbital radius of the Galileans. The surface is dark and red-gray, similar to other captured outer solar system bodies; Himalia is probably a captured asteroid or Kuiper Belt object rather than a native moon. Cassini's distant flyby in 2000 produced the only resolved imagery, showing an elongated body roughly 150×120 km.

Himalia gives its name to the Himalia group, a cluster of small Jovian moons (Elara, Lysithea, Leda, Dia) sharing similar inclined prograde orbits, likely fragments of a common parent body that broke up after capture.

Missions and observations

Every Jupiter-system mission has had an opportunity to image or characterize Himalia. The list below is the Jupiter-system mission catalog; specific Himalia encounters are documented in mission archives.

Mission	Year at Jupiter	Status
Pioneer 10 NASA	1973	Completed
Pioneer 11 NASA	1974	Completed
Voyager 1 NASA	1979	Completed
Voyager 2 NASA	1979	Completed
Ulysses NASA/ESA	1992	Completed
Galileo NASA	1995	Completed
Cassini-Huygens NASA/ESA/ASI	2000	Completed
New Horizons NASA	2007	Completed
Juno NASA	2016	Active
Europa Clipper NASA	2030	On the way
JUICE ESA	2031	On the way

Naming etymology

Himalia was a Greek nymph from the island of Rhodes who bore three sons to Zeus. The name went unused for the moon for nearly seven decades after discovery — Perrine called it 'Jupiter VI,' and the IAU did not formally name it until 1975. The Himalia group naming convention (Jovian outer moons ending in -a for prograde, -e for retrograde) became the IAU standard from the 1970s onward.

Methodology & sources

Diameter, mass, and orbital parameters from JPL Solar System Dynamics — Physical Parameters. Discovery year and discoverer from the JPL Satellite Discovery Circumstances. Naming etymology from the IAU Working Group for Planetary System Nomenclature. Stylized SVG hero composed from NASA / JPL imagery as visual reference; no photographs are reproduced.