Jupiter's Outer Moons

 


Farthest from Jupiter (outward of the Galilean moons) are the eight tiny moons:

Leda Ananke
Himalia Carme
Lysithea Pasiphae
Elara Sinope
Jupiter's eight outer moons fall into two groups: Leda, Himalia, Lysithea and Elara at about 11 million km from Jupiter and Ananke, Carme, Pasiphae and Sinope at about 23 million km. When the first version of The Nine Planets was written that was it. But in recent years several dozen tiny moons in various orbits farther out have been detected.

Leda

Jupiter XIII

Leda ("LEE duh") is the ninth of Jupiter's known satellites and the smallest:
        orbit:    11,094,000 km from Jupiter
        diameter: 16 km
        mass:     5.68e15 kg
Leda was queen of Sparta and the mother, by Zeus in the form of a swan, of Pollux and Helen of Troy.

Discovered by Kowal in 1974.

Leda, Ananke, and Sinope are among the smallest moons in the solar system.


Himalia

Jupiter VI

Himalia ("hih MAL yuh") is the tenth of Jupiter's known satellites:
        orbit:    11,480,000 km from Jupiter
        diameter: 186 km
        mass:     9.56e18 kg
Himalia was a nymph who bore three sons of Zeus (Jupiter).

Discovered by Perrine in 1904.

Unlike the inner satellites, the orbits of Leda, Himalia, Lysithea and Elara are significantly inclined to Jupiter's equator (about 28 degrees).


Lysithea

Jupiter X

Lysithea ("ly SITH ee uh") is the eleventh of Jupiter's known satellites:
        orbit:    11,720,000 km from Jupiter
        diameter: 36 km
        mass:     7.77e16 kg
Lysithea was a daughter of Oceanus and one of Zeus' lovers.

Discovered by Nicholson in 1938.


Elara

Jupiter VII

Elara ("EE lar uh") is the twelfth of Jupiter's known satellites:
        orbit:    11,737,000 km from Jupiter
        diameter: 76 km
        mass:     7.77e17 kg
Elara was the mother by Zeus of the giant Tityus.

Discovered by Perrine in 1905.

Leda, Himalia, Lysithea and Elara may be remnants of a single asteroid that was captured by Jupiter and broken up.


Ananke

Jupiter XII

Ananke ("a NANG kee") is the thirteenth of Jupiter's known satellites:
        orbit:    21,200,000 km from Jupiter
        diameter: 30 km
        mass:     3.82e16 kg
Ananke was the mother of Adrastea, by Jupiter.

Discovered by Nicholson in 1951.

Ananke, Carme, Pasiphae and Sinope have unusual but similar orbits.


Carme

Jupiter XI

Carme ("KAR mee") is the fourteenth of Jupiter's known satellites:
        orbit:    22,600,000 km from Jupiter
        diameter: 40 km
        mass:     9.56e16 kg
Carme was the mother, by Zeus of Britomartis, a Cretan goddess.

Discovered by Nicholson in 1938.

Ananke, Carme, Pasiphae and Sinope are especially unusual in that their orbits are retrograde.


Pasiphae

Jupiter VIII

Pasiphae ("pah SIF ah ee") is the fifteenth of Jupiter's known satellites:
        orbit:    23,500,000 km from Jupiter
        diameter: 50 km
        mass:     1.91e17 kg
Pasiphae was the wife of Minos and mother, by a white bull, of the Minotaur.

Discovered by P. Melotte in 1908.

Ananke, Carme, Pasiphae and Sinope have orbits highly inclined to Jupiter's equator (about 150 degrees).


Sinope

Jupiter IX

Sinope ("sah NOH pee") is the outermost of Jupiter's known confirmed satellites:
        orbit:    23,700,000 km from Jupiter
        diameter: 36 km
        mass:     7.77e16 kg
Sinope was a woman said to have been unsuccessfully (!) courted by Zeus.

Discovered by Nicholson in 1914.

Ananke, Carme, Pasiphae and Sinope may be remnants of a single asteroid that was captured by Jupiter and broken up.


Open Issues

  • Why do they fall into two distinct groups? Are they indeed captured asteroids?
  • We know next to nothing about these moons. Even the basic mass and size data are not very accurate.

Home ... Jupiter ... Callisto ... Leda / ... / Sinope ... S/1999 J 1. ... Data

Bill Arnett; last updated: 1996 April 22

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