Moons of Jupiter

From Wikipedia, the free encyclopedia

Jupiter's outer moons and their highly inclined orbits.

In astronomy, the moons of Jupiter are Jupiter's natural satellites. Sixty-three moons orbiting Jupiter have been discovered.

[edit] Discovery

The Galilean moons. From left to right, in order of increasing distance from Jupiter: Io, Europa, Ganymede, Callisto.

The Galilean moons and their orbits around Jupiter.

Although claims are made for the observation of one of Jupiter's moons by Chinese astronomer Gan De in 364 BC, the first certain observations of Jupiter's satellites are those of Galileo Galilei in 1610, who sighted the four large Galilean moons with his 33x telescope.

No additional satellites were discovered until E.E. Barnard observed Amalthea in 1892. Further discoveries, aided by telescopic photography, followed quickly over the course of the twentieth century, and by 1975, before the Voyagers reached Jupiter, the planet was known to have at least thirteen satellites.

The Voyager 1 mission discovered three inner moons in 1979, bringing the total then known to 16 (17 if one counted Themisto, which had been found but then lost in 1975). The total rested there until 1999. Since then, researchers using sensitive ground-based detectors have recovered Themisto and found a further 46 tiny moons in long, eccentric, generally retrograde orbits. They average 3 kilometres in diameter, and the largest is barely 9 km across. 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 now stands at 63, currently the most of any planet in the solar system. Many additional tiny moons may exist that have not yet been discovered.

On October 6, 1999, the Spacewatch project discovered an asteroid, 1999 UX₁₈. But it was soon realised that this was in fact a previously undiscovered moon of Jupiter, now called Callirrhoe. One year later, between November 23 and December 5, 2000, the team led by Scott S. Sheppard and David C. Jewitt of the University of Hawaii began a systematic search for small irregular moons of Jupiter. The other members of the team included, at various times, Yanga R. Fernández, Eugene A. Magnier, Scott Dahm, Aaron Evans, Henry H. Hsieh, Karen J. Meech, John L. Tonry, David J. Tholen (all from the University of Hawaii), Jan Kleyna (Cambridge University), Brett J. Gladman (University of Toronto), John J. Kavelaars (Hertzberg Institute of Astrophysics), Jean-Marc Petit (Observatoire de Besançon) and Rhiannon Lynne Allen (University of Michigan / University of British Columbia).

The team used the world's two largest CCD cameras, mounted on two of the thirteen telescopes atop Mauna Kea in Hawaii: the Subaru (8.3 m diameter) and the Canada-France-Hawaii (3.6 m). The 2000 observations revealed ten new moons, putting the count at 28 (Themisto had been rediscovered at the beginning of 2000).

The following year, between December 9 and 11, 2001, eleven other moons were discovered, bringing the total to thirty-nine. The year 2002 bore less fruit, netting only one moon, Arche. However, four months later, between February 5 and 9, 2003, twenty-three more moons were found, making for a complete sum of sixty-three moons.

[edit] Table of Jupiter's moons

The moons of Jupiter are listed below by orbital period, from shortest to longest. Moons massive enough for their surfaces to have collapsed into a spheroid are highlighted in blue; these are the four Galilean moons, which are comparable in size to Earth's moon. Irregular, captured moons are indicated by grey shading: light grey for prograde satellites, dark grey for retrograde.

Order	Name (Pronunciation key)			Image	Diameter (km)	Mass (kg)	Semi-major axis (km)(3)	Orbital period (d)(3)(4)	Inclination (°)(5)	Eccentricity	Discovered	Group
1	XVI	Metis	ˈmiːtɪs		60×40×34	~3.6E+16	127 690(1)	+7h 4m 29s(2)	0.06°	0.00002	1980	Amalthea
2	XV	Adrastea	ˌædrəˈstiːə		20×16×14	~2E+15	128 690(1)	+7h 9m 30s(2)	0.03°	0.0015	1979
3	V	Amalthea	ˌæməlˈθiːə		250×146×128	2.08E+18	181 366(1)	+11h 57m 22.67s(2)	0.374°	0.0032	1892
4	XIV	Thebe	ˈθiːbi		116×98×84	~4.3E+17	221 889(1)	+16h 11m 17s(2)	1.076°	0.0175	1980
5	I	Io	ˈaɪoʊ		3660.0×3637.4×3630.6	8.9E+22	421 700(1)	+1.769137786(2)	0.050°	0.0041	1610	Galileans
6	II	Europa	jʊˈroʊpə		3121.6	4.8E+22	671 034(1)	+3.551181041(2)	0.471°	0.0094	1610
7	III	Ganymede	ˈgænɪmiːd		5262.4	1.5E+23	1 070 412(1)	+7.15455296(2)	0.204°	0.0011	1610
8	IV	Callisto	kəˈlɪstoʊ		4820.6	1.1E+23	1 882 709(1)	+16.6890184(2)	0.205°	0.0074	1610
9	XVIII	Themisto	θɪˈmɪstoʊ		8	6.9E+14	7 393 216	+129.87	45.762°	0.2115	1975/2000	Themisto
10	XIII	Leda	ˈliːdə		10	1.1E+16	11 187 781	+241.75	27.562°	0.1673	1974	Himalia
11	VI	Himalia	haɪˈmeɪliə		170	6.7E+18	11 451 971	+250.37	30.486°	0.1513	1904
12	X	Lysithea	laɪˈsɪθiə		36	6.3E+16	11 740 560	+259.89	27.006°	0.1322	1938
13	VII	Elara	ˈɛlərə		86	8.7E+17	11 778 034	+261.14	29.691°	0.1948	1905
14		S/2000 J 11			4	9.0E+13	12 570 424	+287.93	27.584°	0.2058	2001
15	XLVI	Carpo	ˈkɑrpoʊ		3	4.5E+13	17 144 873	+458.62	56.001°	0.2735	2003	Carpo
16		S/2003 J 12			1	1.5E+12	17 739 539	-482.69	142.680°	0.4449	2003	?
17	XXXIV	Euporie	juːˈpɔərɪi		2	1.5E+13	19 088 434	-538.78	144.694°	0.0960	2002	Ananke
18		S/2003 J 3			2	1.5E+13	19 621 780	-561.52	146.363°	0.2507	2003
19		S/2003 J 18			2	1.5E+13	19 812 577	-569.73	147.401°	0.1569	2003
20	XLII	Thelxinoe	θɛlkˈsɪnoʊi		2	1.5E+13	20 453 753	-597.61	151.292°	0.2684	2004
21	XXXIII	Euanthe	juːˈænθi		3	4.5E+13	20 464 854	-598.09	143.409°	0.2000	2002
22	XLV	Helike	ˈhɛlɪki		4	9.0E+13	20 540 266	-601.40	154.586°	0.1374	2003
23	XXXV	Orthosie	ɔrˈθɒsɪi		2	1.5E+13	20 567 971	-602.62	142.366°	0.2433	2002
24	XXIV	Iocaste	ˌaɪəˈkæsti		5	1.9E+14	20 722 566	-609.43	147.248°	0.2874	2001
25		S/2003 J 16			2	1.5E+13	20 743 779	-610.36	150.769°	0.3184	2003
26	XXVII	Praxidike	prækˈsɪdɪki		7	4.3E+14	20 823 948	-613.90	144.205°	0.1840	2001
27	XXII	Harpalyke	hɑrˈpælɪki		4	1.2E+14	21 063 814	-624.54	147.223°	0.2440	2001
28	XL	Mneme	ˈniːmi		2	1.5E+13	21 129 786	-627.48	149.732°	0.3169	2003
29	XXX	Hermippe	hɚˈmɪpi		4	9.0E+13	21 182 086	-629.81	151.242°	0.2290	2002	Ananke?
30	XXIX	Thyone	θaɪˈoʊni		4	9.0E+13	21 405 570	-639.80	147.276°	0.2525	2002	Ananke
31	XII	Ananke	əˈnæŋki		28	3.0E+16	21 454 952	-642.02	151.564°	0.3445	1951
32		S/2003 J 17			2	1.5E+13	22 134 306	-672.75	162.490°	0.2379	2003	Carme
33	XXXI	Aitne	ˈaɪtni		3	4.5E+13	22 285 161	-679.64	165.562°	0.3927	2002
34	XXXVII	Kale	ˈkeɪli		2	1.5E+13	22 409 207	-685.32	165.378°	0.2011	2002
35	XX	Taygete	teiˈɪdʒɪti		5	1.6E+14	22 438 648	-686.67	164.890°	0.3678	2001
36		S/2003 J 19			2	1.5E+13	22 709 061	-699.12	164.727°	0.1961	2003
37	XXI	Chaldene	kælˈdiːni		4	7.5E+13	22 713 444	-699.33	167.070°	0.2916	2001
38		S/2003 J 15			2	1.5E+13	22 720 999	-699.68	141.812°	0.0932	2003	Ananke?
39		S/2003 J 10			2	1.5E+13	22 730 813	-700.13	163.813°	0.3438	2003	Carme?
40		S/2003 J 23			2	1.5E+13	22 739 654	-700.54	148.849°	0.3930	2004	Pasiphaë
41	XXV	Erinome	ɪˈrɪnəmi		3	4.5E+13	22 986 266	-711.96	163.737°	0.2552	2001	Carme
42	XLI	Aoede	eɪˈiːdi		4	9.0E+13	23 044 175	-714.66	160.482°	0.6011	2003	Pasiphaë
43	XLIV	Kallichore	kəˈlɪkəri		2	1.5E+13	23 111 823	-717.81	164.605°	0.2041	2003	Carme?
44	XXIII	Kalyke	ˈkælɪki		5	1.9E+14	23 180 773	-721.02	165.505°	0.2139	2001	Carme
45	XI	Carme	ˈkɑrmi		46	1.3E+17	23 197 992	-721.82	165.047°	0.2342	1938
46	XVII	Callirrhoe	kəˈlɪroʊi		9	8.7E+14	23 214 986	-722.62	139.849°	0.2582	2000	Pasiphaë
47	XXXII	Eurydome	jʊˈrɪdəmi		3	4.5E+13	23 230 858	-723.36	149.324°	0.3769	2002	Pasiphaë?
48	XXXVIII	Pasithee	pəˈsɪθɪi		2	1.5E+13	23 307 318	-726.93	165.759°	0.3288	2002	Carme
49	XLVIII	Cyllene	sɪˈliːni		2	1.5E+13	23 396 269	-731.10	140.148°	0.4115	2003	Pasiphaë
50	XLVII	Eukelade	juːˈkɛlədi		4	9.0E+13	23 483 694	-735.20	163.996°	0.2828	2003	Carme
51		S/2003 J 4			2	1.5E+13	23 570 790	-739.29	147.175°	0.3003	2003	Pasiphaë
52	VIII	Pasiphaë	pəˈsɪfeɪi		60	3.0E+17	23 609 042	-741.09	141.803°	0.3743	1908
53	XXXIX	Hegemone	hɪˈdʒɛməni		3	4.5E+13	23 702 511	-745.50	152.506°	0.4077	2003
54	XLIII	Arche	ˈɑrki		3	4.5E+13	23 717 051	-746.19	164.587°	0.1492	2002	Carme
55	XXVI	Isonoe	aɪˈsɒnoʊi		4	7.5E+13	23 800 647	-750.13	165.127°	0.1775	2001
56		S/2003 J 9			1	1.5E+12	23 857 808	-752.84	164.980°	0.2761	2003
57		S/2003 J 5			4	9.0E+13	23 973 926	-758.34	165.549°	0.3070	2003
58	IX	Sinope	sɪˈnoʊpi		38	7.5E+16	24 057 865	-762.33	153.778°	0.2750	1914	Pasiphaë
59	XXXVI	Sponde	ˈspɒndi		2	1.5E+13	24 252 627	-771.60	154.372°	0.4431	2002
60	XXVIII	Autonoe	ɔˈtɒnoʊi		4	9.0E+13	24 264 445	-772.17	151.058°	0.3690	2002
61	XLIX	Kore	ˈkɔəri		2	1.5E+13	23 345 093	-776.02	137.371°	0.1951	2003
62	XIX	Megaclite	ˌmɛgəˈklaɪti		5	2.1E+14	24 687 239	-792.44	150.398°	0.3077	2001
63		S/2003 J 2			2	1.5E+13	30 290 846	-1077.02	153.521°	0.1882	2003	?

• ⁽¹⁾ Computed using the IAU-MPC Satellites Ephemeris Service µ value
• ⁽²⁾ Source: JPL/NASA
• ⁽³⁾ Source (for Themisto outward): IAU-MPC Satellites Ephemeris Service
• ⁽⁴⁾ Periods with negative values are retrograde.
• ⁽⁵⁾ Computed from IAG Travaux 2001 for Metis through Callisto, showing inclination to Jupiter's equator; taken from IAU-MPC Satellites Ephemeris Service orbital elements for the others, using inclination to the local Laplace plane.

[edit] Grouping the moons

Jupiter's satellites fall into two main categories:

• Regular satellites, which consist of the Amalthea group of inner moons and the four Galilean moons, both of which groups formed in situ.
• Irregular satellites, substantially smaller objects with more distant and eccentric orbits; most of these satellites were bodies with originally heliocentric orbits that were captured by Jupiter's gravity.

Irregular satellites of Jupiter.

The first diagram illustrates the orbits of the irregular satellites of Jupiter discovered so far. The eccentricity of the orbits is represented by the segments (extending from the pericentre to the apocentre) with the inclination represented on Y axis. The satellites above the axis are prograde, the satellites beneath are retrograde. The X axis is labelled in Gm (million km) and the fraction of the Hill sphere's (gravitational influence) radius (~53 Gm for Jupiter). The following diagram shows separately the distribution of inclination versus eccentricity for the retrograde satellites, facilitating the identification of the groupings.

[edit] Prograde irregular moons

Himalia group is "tight", spread over barely 1.4 Gm in semi-major axis and 1.6° in inclination (27.5 ± 0.8°). The eccentricities vary between 0.11 and 0.25.

Themisto and Carpo are isolated in space.

[edit] Retrograde irregular moons

Retrograde satellites: inclinations (°) vs eccentricities with Carme's (orange) and Ananke's (yellow) groups identified.

What is left of the outer retrograde irregular satellites of Jupiter can be grouped into three families, based on shared orbital characteristics and bearing the name of the largest member in each case. These families are clumps in semi-major axis, but also in inclination and in eccentricity.

Carme's group is obvious, centered on a = 23 404 Mm; i = 165.2±0.3° and e = 0.238–0.272. Only S/2003 J 10 seems somewhat apart, because of its great eccentricity.

Ananke's group is centered on a = 21 276 Mm; i = 149.0±0.5° and e = 0.216–0.244; but its borders are less definite. The eight core members (S/2003 J 16, Mneme, Euanthe, Orthosie, Harpalyke, Praxidike, Thyone, Thelxinoe, Ananke, Iocaste) are well-clumped, but the attribution of the remaining eight members to the group is debatable to varying degrees.

Pasiphaë's group, finally, picks up the remainder, with the exception of the moons at the inner and outer limits of the groups (S/2003 J 12 and S/2003 J 2); it is centered on a = 23 624 Mm; i = 151.4±6.9° and e = 0.156–0.432 (note the much larger spreads). If it is real, it must be ancient to explain the dispersion of its membership.

S/2003 J 12, and S/2003 J 2, the most exterior moon, are again isolated.

[edit] Naming

Main article: Naming of natural satellites

The seven satellites discovered between 1904 and 1951—Himalia, Elara, Pasiphaë, Sinope, Lysithea, Carme and Ananke—were not officially named until 1975, 24–71 years after being discovered. They were for the most part simply known by their Roman numeral designations, Jupiter VI through Jupiter XII, although various names were proposed in 1955, 1962, and 1973.

Some asteroids share the same names as moons of Jupiter: 9 Metis, 38 Leda, 52 Europa, 85 Io, 113 Amalthea, 239 Adrastea. Two more asteroids previously shared the names of Jovian moons until spelling differences were made permanent by the IAU:

• Ganymede and asteroid 1036 Ganymed
• Callisto and asteroid 204 Kallisto

See also: Name conflicts of solar system objects

[edit] See also

• Galilean moons
• Jupiter's moons in fiction
• Natural satellites of Earth · Mars · Saturn · Uranus · Neptune

[edit] Notes

[edit] References

• Scott S. Sheppard, David C. Jewitt An abundant population of small irregular satellites around Jupiter, Nature, 423 (May 2003), pp.261-263 Full text(pdf).
• Scott S. Sheppard, David C. Jewitt, Carolyn Porco Jupiter's outer satellites and Trojans, In: Jupiter. The planet, satellites and magnetosphere Edited by Fran Bagenal, Timothy E. Dowling, William B. McKinnon. Cambridge planetary science, Vol. 1, Cambridge, UK: Cambridge University Press, ISBN 0-521-81808-7, 2004, p. 263 - 280. Full text(pdf).

[edit] External links

• Jupiter's Moons by NASA's Solar System Exploration
• Jupiter satellite data
• 43 more moons orbiting Jupiter

v • d • e Jupiter
Major Moons	Io · Europa · Ganymede · Callisto
Characteristics	Cloud pattern on Jupiter · Great Red Spot · Jupiter's magnetosphere · Oval BA · Rings of Jupiter · Moons
Exploration	Pioneer program · Voyager program · Galileo (spacecraft) · Juno (spacecraft) · Europa Orbiter
Other	Jupiter-crosser asteroid · Earthly Branches · Colonization · Jupiter mass · Comet Shoemaker-Levy 9

v • d • e Natural satellites of the Solar System
Planetary satellites	Terrestrial · Martian · Jovian · Saturnian · Uranian · Neptunian
Other satellite systems	Plutonian · Eridian · Asteroid satellites
Largest satellites	Ganymede · Titan · Callisto · Io · Moon · Europa · Triton Titania · Rhea · Oberon · Iapetus · Charon · Umbriel · Ariel · Dione · Tethys  · Enceladus · Miranda · Proteus · Mimas
Inner satellites · Trojans · Irregulars · List · List by diameter · Timeline of discovery · Naming

v • d • e The Solar System
The Sun · Mercury · Venus · Earth · Mars · Ceres · Jupiter · Saturn · Uranus · Neptune · Pluto · Eris
Planets · Dwarf planets · Moons: Terrestrial · Martian · Jovian · Saturnian · Uranian · Neptunian · Plutonian · Eridian
Small bodies:   Meteoroids · Asteroids/Asteroid moons (Asteroid belt) · Centaurs · TNOs (Kuiper belt/Scattered disc) · Comets (Oort cloud)
See also astronomical objects, the solar system's list of objects, sorted by radius or mass, and the Solar System Portal