Jupiter, moons

The largest planet in the solar system, Jupiter, has 63 known satellites. With one exception – Themisto – these moons fall into four major groups. The inner group of Metis, Adrastea, Amalthea, and Thebe are small- to medium-sized, orbit in nearly-circular paths at less than 200,000 km, and were discovered as a result of images sent back by the Voyager probes. The Galilean moons, Io, Europa, Ganymede, and Callisto, have orbital radii of 400,000–2,000,000 km and are among the largest satellites in the Solar System. The third group includes Leda, Himalia, Lysithea, and Elara, which were discovered in the 20th century but pre-Voyager, and S/2000 J11; all have diameters of less than 200 km and orbits of 11 to 13 million km with inclinations of 26–29°. The fourth group, composed of several subgroups, includes four moons, Ananke, Carme, Pasiphae, and Sinope, whose 20th-century discovery predates Voyager, plus many others found recently; all, with the exception of Pasiphae, have diameters of less than 50 km and high-inclination, retrograde orbits with radii of 19 to 30 million km. It is thought that the three groups of smaller moons may each have a common origin, perhaps as a larger moon or captured body that broke up into the existing moons of each group.

All Jupiter's moons are tidally locked with the planet so that their rotational periods and orbital periods are the same. All the known moons beyond Carpo move in retrograde orbits. For further details on some of the moons that have been given proper names, see individual entries (click on the names in the table below). They are listed in order of increasing distance from the planet.

The values of semimajor axis and orbital period, eccentricity, and inclination, for all the moons of Jupiter beyond and including Themisto were obtained from the Natural Satellites Empheris Service of the IAU Minor Planet Center (http://cfa-www.harvard.edu/iau/mpc.html).

moon	semimajor axis (km)	orbital period (days)	orbital eccentricity	orbital incl. (°)	diameter (km)
Metis	127,690	0.2948	0.00002	0.06	60 × 40 × 34
Adrastea	128,690	0.2983	0.0015	0.03	20 × 16 × 14
Amalthea	181,370	0.4982	0.0032	0.374	250 × 146 × 128
Thebe	221,890	0.6745	0.0175	1.076	116 × 98 × 84
Io	421,700	1.769	0.0041	0.050	3,643
Europa	671,030	3.551	0.0094	0.471	3,122
Ganymede	1,070,410	7.155	0.0011	0.204	5,262
Callisto	1,882,710	16.69	0.0074	0.205	4,821
Themisto	7,393,220	129.87	0.2116	45.762	8
Leda	11,098,500	238.86	0.1801	27.376	10
Himalia	11,377,500	247.93	0.1361	29.872	170
Lysithea	11,756,000	260.40	0.1277	26.600	36
Elara	11,763,800	260.66	0.1948	30.646	86
S/2000 J11	12,570,600	287.93	0.2058	27.584	4
Carpo	17,144,900	458.62	0.2736	56.001	3
S/2003 J12	17,739,500	-482.69 (r)	0.4449	142.686	1
Euporie	19,088,400	-538.78 (r)	0.0960	144.694	2
S/2003 J3	19,621,800	-561.52 (r)	0.2507	146.363	2
S/2003 J18	19,812,600	-569.73 (r)	0.1570	147.401	2
Ananke	20,439,100	-596.96 (r)	0.3121	150.187	28
Thelxinoe	20,453,800	-597.61 (r)	0.2685	151.293	2
Euanthe	20,464,900	-598.09 (r)	0.2001	143.409	3
Helike	20,540,300	-601.40 (r)	0.1375	154.587	4
Orthosie	20,568,000	-602.62 (r)	0.2433	142.367	2
Iocaste	20,722,600	-609.43 (r)	0.2874	147.249	5
S/2003 J16	20,743,800	-610.36 (r)	0.3185	150.769	2
Praxidike	20,823,900	-613.90 (r)	0.1840	144.206	7
Harpalyke	21,063,800	-624.54 (r)	0.2441	147.224	4
Mneme	21,129,800	-627.48 (r)	0.3169	149.733	2
Hermippe	21,182,100	-629.81 (r)	0.2290	151.242	4
Thyone	21,405,600	-639.80 (r)	0.2526	147.276	4
S/2003 J17	22,134,300	-672.75 (r)	0.2379	162.491	2
Aitne	22,285,200	-679.64 (r)	0.3927	165.563	3
Kale	22,409,200	-685.32 (r)	0.2011	165.379	2
Taygete	22,438,600	-686.67 (r)	0.3678	164.890	5
S/2003 J19	22,709,100	-699.12 (r)	0.1961	164.728	2
Chaldene	22,713,400	-699.33 (r)	0.2916	167.071	4
S/2003 J15	22,721,000	-699.68 (r)	0.0932	141.813	2
S/2003 J10	22,730,800	-700.13 (r)	0.3439	163.813	2
S/2003 J23	22,739,700	-700.54 (r)	0.3931	148.850	2
Pasiphaë	22,928,200	-709.27 (r)	0.2914	144.292	60
Erinome	22,986,300	-711.96 (r)	0.2552	163.738	3
Aoede	23,044,200	-714.66 (r)	0.6012	160.482	4
Kallichore	23,111,800	-717.81 (r)	0.2042	164.605	2
Kalyke	23,180,800	-721.02 (r)	0.2140	165.505	5
Callirrhoe	23,215,000	-722.62 (r)	0.2582	139.850	9
Eurydome	23,230,900	-723.36 (r)	0.3770	149.324	3
Pasithee	23,307,300	-726.93 (r)	0.3289	165.759	2
Carme	22,371,300	-683.58 (r)	0.2593	165.943	46
Cyllene	23,396,300	-731.10 (r)	0.4116	140.149	2
Eukelade	23,483,700	-735.20 (r)	0.2829	163.996	4
S/2003 J4	23,570,800	-739.29 (r)	0.3003	147.176	2
Hegemone	23,702,500	-745.50 (r)	0.4077	152.506	3
Arche	23,717,100	-746.19 (r)	0.1492	164.587	3
Isonoe	23,800,600	-750.13 (r)	0.1776	165.128	4
S/2003 J9	23,857,800	-752.84 (r)	0.2762	164.980	1
S/2003 J5	23,973,900	-758.34 (r)	0.3071	165.550	4
Sinope	24,130,600	-765.79 (r)	0.1970	155.005	38
Sponde	24,252,600	-771.60 (r)	0.4432	154.373	2
Autonoe	24,264,400	-772.17 (r)	0.3690	151.058	4
Kore	24,345,100	-776.02 (r)	0.1951	137.372	2
Megaclite	24,687,200	-792.44 (r)	0.3078	150.398	5
S/2003 J2	30,290,800	-1077.02 (r)	0.1882	153.521	2

r = retrograde

the four largest (Galilean) moons of Jupiter

A montage, to scale, of the four largest moons of Jupiter and Jupiter's Great Red Spot

Archived news

Jovian moons galore (Mar 7, 2003)
Jupiter's moon count surges to 28 (Jan 8, 2001)

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• PLANETS AND MOONS

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