Jupiter's natural satellites

Jupiter has many natural satellites.

The Voyager 1 mission discovered 3 moons in 1979, bringing the total then known to 16. The total rested there until 1999, since when sensitive ground-based detectors have found a further 47 tiny moons in long, eccentric, generally retrograde orbits around Jupiter. Most of these are no larger than a kilometer or two in diameter. All of these moons are thought to be captured asteroidal or perhaps cometary bodies, possibly fragmented into several pieces, but very little is actually known about them. The total number of known moons of Jupiter is therefore 63, currently the most of any planet in the solar system. Many additional tiny moons may exist that have not yet been discovered.

On April 4, 2003, the official moon count for Jupiter jumped to 58. The latest discoveries were made by a team led by Scott Sheppard and David Jewitt at the University of Hawaii, along with Jan Kleyna of Cambridge University. The discoveries were made using the world's two largest digital cameras at the Subaru and Canada-France-Hawaii telescopes atop Mauna Kea in Hawaii. All six newfound satellites are estimated to be about 2 kilometers wide. The same team earlier this year found the smallest known moons, a pair of 1-kilometer satellites orbiting the giant planet.

On May 15, 2003, Scott Sheppard published in the journal Nature his discovery of 23 new moons around the giant planet. This brought the total number of known moons to at least 61. Now there are 63 known moons.

References: [1] [1]

Name Diameter (km) Mass (kg) Mean orbital
radius (km) Orbital period Inclination Group
Metis 40 (40 × 60) 9.56×10¹⁶ 127,600 7.08 hours 0.0° small inner
regulars
Adrastea 20 (23 × 20 × 15) 1.91×10¹⁶ 134,000 7.11 hours 0.0°
Amalthea 189 (270 × 166 × 150) 7.17×10¹⁸ 181,300 11.92 hours 0.4°
Thebe 100 (100 × 90) 7.77×10¹⁷ 222,000 16.23 hours 1.1°
Io 3632 8.92×10²² 421,600 1.76 days 0.0° Galilean
satellites
Europa 3138 4.8×10²² 670,900 3.55 days 0.5°
Ganymede 5262 1.49×10²³ 1,070,000 7.16 days 0.2°
Callisto 4820 1.08×10²³ 1,883,000 16.69 days 0.3°
Themisto 9 Unknown 7,507,000 130.0 days 43.1°
Leda 18 5.68×10¹⁵ 11,165,000 240.9 days 27.5° Himalia
prograde
irregular
group
Himalia 184 9.56×10¹⁸ 11,461,000 250.6 days 27.5°
Lysithea 38 7.77×10¹⁶ 11,717,000 259.2 days 28.3°
Elara 78 7.77×10¹⁷ 11,741,000 259.6 days 26.6°
S/2000 J 11 4 Unknown 12,555,000 287.0 days 28.3°
S/2003 J 20 3 Unknown 17,056,000 455.1 days 55.1°
S/2003 J 3 2 Unknown 18,291,000 505.4 days 143.7° Ananke group?
S/2003 J 12 1 Unknown 18,952,000 533.0 days 145.8° Ananke group?
Euporie 2 Unknown 19,302,000 550.7 days 145.8° Ananke group
S/2003 J 16 2 Unknown 20,434,000 596.8 days 148.6° Ananke group
S/2003 J 21 2 Unknown 20,500,000 599.6 days 148.0° Ananke group
S/2003 J 18 2 Unknown 20,683,000 607.7 days 146.5° Ananke group
Orthosie 2 Unknown 20,721,000 622.6 days 145.9° Ananke group
Euanthe 3 Unknown 20,799,000 620.6 days 148.9° Ananke group
S/2003 J 6 4 Unknown 20,923,000 618.3 days 156.1°
Thyone 4 Unknown 20,940,000 627.3 days 148.5° Ananke group
Harpalyke 4 Unknown 21,105,000 623.3 days 148.6° Ananke group
Hermippe 4 Unknown 21,131,000 633.9 days 150.7° Ananke group
Praxidike 7 Unknown 21,147,000 625.3 days 149.0° Ananke group
Iocaste 5 Unknown 21,269,000 631.5 days 149.4° Ananke group
Ananke 28 3.82×10¹⁶ 21,276,000 610.5 days 148.9° Ananke group
S/2003 J 22 2 Unknown 21,403,000 639.6 days 151.0° Ananke group?
S/2003 J 15 2 Unknown 22,012,000 667.2 days 140.8°
S/2003 J 11 2 Unknown 22,335,000 681.9 days 163.9° Carme group?
S/2003 J 9 1 Unknown 22,382,000 684.1 days 164.4° Carme group?
S/2003 J 17 2 Unknown 22,511,000 690.0 days 164° Carme group?
S/2003 J 19 2 Unknown 22,746,000 700.8 days 162.9° Carme group?
Eurydome 3 Unknown 22,865,000 717.3 days 150.3° Pasiphaë group
S/2002 J 1 3 Unknown 22,931,000 723.9 days 165.0° Carme group
Autonoe 4 Unknown 23,039,000 762.7 days 152.9° Pasiphaë group
Pasithee 2 Unknown 23,096,000 719.5 days 165.1° Carme group
Chaldene 4 Unknown 23,179,000 723.8 days 165.2° Carme group
S/2003 J 4 2 Unknown 23,196,000 721.7 days 144.9° Pasiphaë group?
Kale 2 Unknown 23,217,000 729.5 days 165.0° Carme group
Isonoe 4 Unknown 23,217,000 725.5 days 165.2° Carme group
Aitne 3 Unknown 23,231,000 730.2 days 165.1° Carme group
Erinome 3 Unknown 23,279,000 728.3 days 164.9° Carme group
Taygete 5 Unknown 23,360,000 732.2 days 165.2° Carme group
Carme 46 9.56×10¹⁶ 23,404,000 702.3 days 164.9° Carme group
Sponde 2 Unknown 23,487,000 748.3 days 151.0° Pasiphaë group
S/2003 J 13 2 Unknown 23,545,000 738.1 days 141.0°
Kalyke 5 Unknown 23,583,000 743.0 days 165.2° Carme group
Pasiphaë 58 1.91×10¹⁷ 23,624,000 708.0 days 151.4° Pasiphaë group
S/2003 J 7 4 Unknown 23,744,000 747.5 days 159.4° Pasiphaë group?
Megaclite 6 Unknown 23,806,000 752.8 days 152.8° Pasiphaë group
Sinope 38 7.77×10¹⁶ 23,939,000 724.5 days 158.1° Pasiphaë group
S/2003 J 23 2 Unknown 23,991,000 759.1 days 149.2° Pasiphaë group
S/2003 J 5 4 Unknown 24,020,000 760.5 days 165.0° Carme group?
Callirrhoe 7 Unknown 24,102,000 758.8 days 147.1° Pasiphaë group
S/2003 J 10 2 Unknown 24,185,000 768.4 days 164.1° Carme group?
S/2003 J 8 4 Unknown 24,448,000 781.0 days 152.6° Pasiphaë group?
S/2003 J 1 4 Unknown 24,491,000 783.0 days 163.4° Carme group?
S/2003 J 14 2 Unknown 24,974,000 806.3 days 140.9°
S/2003 J 2 2 Unknown 28,494,000 982.6 days 151.8°

The orbits of S/2003 J 1 through S/2003 J 23 are not yet precisely determined.

Until 2002, it appeared that the outer retrograde irregular satellites could all be assigned to one of three groups based on inclination and mean distance from Jupiter:

Ananke group

i = 145° – 151°

a = 19,302,000 – 21,276,000 km

Carme group

i = 164.9° – 165.2°

a = 22,931,000 – 23,583,000 km

Pasiphaë group

i = 147° – 153° (Sinope 158°)

a = 22,865,000 – 24,102,000 km

The provisionally calculated orbits for some of the 2003 discoveries do not appear to fit into any of these groups, even with modest extensions of the range limits.

Note that the outer satellites do not follow the simple period / axis relationship suggested by Kepler's third law because of the gravitational influence of the sun distorting the orbits.

Table of contents

1 Naming notes
2 See also
3 External links

Naming notes

Some asteroids share the same names as moons of Jupiter: 9 Metis, 38 Leda, 52 Europa, 85 Io, 113 Amalthea, 239 Adrastea.

Note that the satellites discovered between 1904 and 1951 (Himalia, Elara, Pasiphaë, Sinope, Lysithea, Carme and Ananke) were not officially named until 1975, well after their discoverers had passed away. They were simply known by their Roman numeral designations (Jupiter VI through Jupiter XII). See Naming of natural satellites.