Jupiter's natural satellites
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Jupiter has 63 known natural satellites.
Contents |
Discovery of the moons
Image:Galilean satellites.jpg The first moons of Jupiter to be discovered were the large Galilean moons, discovered by Galileo in 1610. An earlier discovery by ancient Chinese astronomer Gan De may have occurred in 362 BC. Over the next four centuries after Galileo, nine smaller moons were discovered by ground-based astronomers.
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.
The most recent discoveries
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, on December 9-11, 2001, eleven other moons were discovered, bringing the total to 39. The year 2002 bore less fruit, netting only one moon, Arche. However, four months later, between February 5 and 9, 2003, 23 more moons were found, making for a complete sum of 63 moons.
References:
- David C. Jewitt, Scott S. Sheppard, An abundant population of small irregular satellites around Jupiter, Nature, Vol 423, p. 261, May 2003
- David C. Jewitt, Scott S. Sheppard and Carolyn Porco, Jupiter's Outer Satellites and Trojans, Nov 2003
- New Satellites of Jupiter Discovered in 2003
Table of known moons
The Jovian moons are listed here by orbital period, from shortest to longest. Moons massive enough for their surfaces to have collapsed into a spheroid are highlighted in purple; these are the "Galilean Moons", which are comparable in size to Earth's moon. Irregular (captured) moons are indicated by light grey.
Name | Diameter (km) | Mass (kg) | Orbital radius (km)(3) | Orbital period (d)(3) | Inclination (°)(4) (to Jupiter's equator) | Eccentricity | Group | |
---|---|---|---|---|---|---|---|---|
Metis | mee'-təs | 43 | 1.2E+17 | 127 690(1) | 0.294780(2) | 0.000° | 0.0012 | Amalthea |
Adrastea | ad'-rə-stee'-ə | 26×20×16 | 7.5E+15 | 128 690(1) | 0.29826(2) | 0.000° | 0.0018 | |
Amalthea | am'-əl-thee'-ə | 262×146×134 | 2.1E+18 | 181 170(1) | 0.49817905(2) | 0.360° | 0.0031 | |
Thebe | thee'-bee | 110×90 | 1.5E+18 | 221 700(1) | 0.6745(2) | 0.901° | 0.0177 | |
Io | eye'-oe | 3660.0×3637.4×3630.6 | 8.9E+22 | 421 700(1) | 1.769137786(2) | 0.050° | 0.0041 | Galileans |
Europa | ew-roe'-pə | 3121.6 | 4.8E+22 | 671 034(1) | 3.551181041(2) | 0.471° | 0.0094 | |
Ganymede | gan'-ə-meed | 5262.4 | 1.5E+23 | 1 070 412(1) | 7.15455296(2) | 0.204° | 0.0011 | |
Callisto | kə-lis'-toe | 4820.6 | 1.1E+23 | 1 882 709(1) | 16.6890184(2) | 0.205° | 0.0074 | |
Themisto | thə-mis'-toe | 8 | 6.9E+14 | 7 391 645 | 129.827611 | 15.346° | 0.2006 | Themisto |
Leda | lee'-də | 20 | 1.1E+16 | 11 097 245 | 238.824159 | 27.210° | 0.1854 | Himalia |
Himalia | hye-mal'-ee-ə | 170 | 6.7E+18 | 11 432 435 | 249.726305 | 29.590° | 0.1443 | |
Lysithea | lye-sith'-ee-ə | 36 | 6.3E+16 | 11 653 225 | 256.995413 | 25.771° | 0.1132 | |
Elara | ee'-lər-ə | 86 | 8.7E+17 | 11 683 115 | 257.984888 | 30.663° | 0.1723 | |
S/2000 J 11 | 4 | 9.0E+13 | 12 570 575 | 287.931046 | 26.169° | 0.2058 | ||
Carpo | kar'-poe | 3 | 4.5E+13 | 17 144 875 | 458.624818 | 55.098° | 0.2736 | Carpo |
S/2003 J 12 | 1 | 1.5E+12 | 17 739 540 | 482.691255 | 134.861° | 0.4449 | ? | |
Euporie | ew-por'-ee-ə | 2 | 1.5E+13 | 19 088 435 | 538.779839 | 131.854° | 0.0960 | Ananke? |
S/2003 J 3 | 2 | 1.5E+13 | 19 621 780 | 561.517739 | 111.592° | 0.2507 | ||
S/2003 J 18 | 2 | 1.5E+13 | 19 812 575 | 569.728015 | 98.461° | 0.1570 | ||
Thelxinoe | thel-zin'-oe-ee | 2 | 1.5E+13 | 20 453 755 | 597.606695 | 102.844° | 0.2685 | Ananke? |
Euanthe | ew-an'-thee | 3 | 4.5E+13 | 20 464 855 | 598.093368 | 123.649° | 0.2000 | Ananke |
Helike | hel'-ə-kee | 4 | 9.0E+13 | 20 540 265 | 601.401918 | 120.908° | 0.1375 | Ananke? |
Orthosie | or-thoe'-see-ə | 2 | 1.5E+13 | 20 567 970 | 602.619143 | 101.861° | 0.2433 | |
Iocaste | eye'-oe-kas'-tee | 5 | 1.9E+14 | 20 722 565 | 609.426611 | 127.043° | 0.2874 | Ananke |
S/2003 J 16 | 2 | 1.5E+13 | 20 743 780 | 610.362159 | 149.279° | 0.3185 | ||
Ananke | ə-nang'-kee | 28 | 3.0E+16 | 20 815 225 | 613.518491 | 149.526° | 0.3963 | |
Praxidike | prak-sid'-ə-kee | 7 | 4.3E+14 | 20 823 950 | 613.904099 | 132.099° | 0.1840 | |
Harpalyke | har-pal'-ə-kee | 4 | 1.2E+14 | 21 063 815 | 624.541797 | 143.944° | 0.2441 | |
Hermippe | hər-mip'-ee | 4 | 9.0E+13 | 21 182 085 | 629.809040 | 149.058° | 0.2290 | Ananke? |
Thyone | thye-oe'-nee | 4 | 9.0E+13 | 21 405 570 | 639.802554 | 116.088° | 0.2526 | Ananke |
Mneme | nee'-mee | 2 | 1.5E+13 | 21 427 110 | 640.768660 | 147.647° | 0.2214 | |
S/2003 J 17 | 2 | 1.5E+13 | 22 134 305 | 672.751882 | 139.842° | 0.2379 | Carme | |
Aitne | et'-nee | 3 | 4.5E+13 | 22 285 160 | 679.641347 | 143.251° | 0.3927 | |
Kale | kay'-lee | 2 | 1.5E+13 | 22 409 210 | 685.323873 | 133.342° | 0.2011 | |
Taygete | tay-ij'-ə-tee | 5 | 1.6E+14 | 22 438 650 | 686.674715 | 140.521° | 0.3678 | |
S/2003 J 19 | 2 | 1.5E+13 | 22 709 060 | 699.124764 | 140.956° | 0.1961 | ||
Chaldene | kal-dee'-nee | 4 | 7.5E+13 | 22 713 445 | 699.326904 | 119.572° | 0.2916 | |
S/2003 J 15 | 2 | 1.5E+13 | 22 721 000 | 699.676116 | 109.168° | 0.0932 | Ananke? | |
S/2003 J 10 | 2 | 1.5E+13 | 22 730 815 | 700.129403 | 115.021° | 0.3438 | Carme? | |
S/2003 J 23 | 2 | 1.5E+13 | 22 739 655 | 700.537990 | 137.576° | 0.3931 | Pasiphaë | |
Erinome | err-rin'-ə-mee | 3 | 4.5E+13 | 22 986 265 | 711.964625 | 143.354° | 0.2552 | Carme |
Aoede | ay-ee'-dee | 4 | 9.0E+13 | 23 044 175 | 714.656754 | 112.763° | 0.6012 | Pasiphaë |
Kallichore | kə-lik'-ə-ree | 2 | 1.5E+13 | 23 111 825 | 717.806112 | 141.240° | 0.2042 | Carme? |
Kalyke | kal'-ə-kee | 5 | 1.9E+14 | 23 180 775 | 721.020662 | 137.125° | 0.2140 | Carme |
Eurydome | ew-rid'-ə-mee | 3 | 4.5E+13 | 23 230 860 | 723.358859 | 143.033° | 0.3770 | Pasiphaë? |
S/2003 J 14 | 2 | 1.5E+13 | 23 238 595 | 723.720459 | 138.885° | 0.2462 | Pasiphaë | |
Pasithee | pə-sith'-ee-ə | 2 | 1.5E+13 | 23 307 320 | 726.932963 | 144.112° | 0.3289 | Carme |
Cyllene | sə-lee'-nee | 2 | 1.5E+13 | 23 396 270 | 731.098603 | 115.507° | 0.4116 | Pasiphaë |
Eukelade | ew-kel'-ə-dee | 4 | 9.0E+13 | 23 483 695 | 735.199980 | 118.384° | 0.2829 | Carme |
S/2003 J 4 | 2 | 1.5E+13 | 23 570 790 | 739.293961 | 98.660° | 0.3003 | Pasiphaë | |
Hegemone | hə-jem'-ə-nee | 3 | 4.5E+13 | 23 702 510 | 745.500007 | 150.314° | 0.4077 | |
Arche | ar'-kee | 3 | 4.5E+13 | 23 717 050 | 746.185469 | 146.289° | 0.1492 | Carme |
Carme | kar'-mee | 46 | 1.3E+17 | 23 734 465 | 747.008062 | 120.659° | 0.3122 | |
Isonoe | eye-son'-oe-ee | 4 | 7.5E+13 | 23 832 630 | 751.646937 | 118.554° | 0.1665 | |
S/2003 J 9 | 1 | 1.5E+12 | 23 857 810 | 752.838751 | 135.452° | 0.2762 | ||
S/2003 J 5 | 4 | 9.0E+13 | 23 973 925 | 758.341296 | 117.922° | 0.3071 | ||
Pasiphaë | pə-sif'-ə-ee | 60 | 3.0E+17 | 24 094 770 | 764.082032 | 143.037° | 0.2953 | Pasiphaë |
Sinope | sə-noe'-pee | 38 | 7.5E+16 | 24 214 390 | 769.779665 | 146.657° | 0.2468 | |
Sponde | spon'-dee | 2 | 1.5E+13 | 24 252 625 | 771.603566 | 112.409° | 0.4432 | |
Autonoe | aw-ton'-oe-ee | 4 | 9.0E+13 | 24 264 445 | 772.167762 | 129.073° | 0.3690 | |
Callirrhoe | kə-lirr'-oe-ee | 9 | 8.7E+14 | 24 356 030 | 776.543335 | 131.895° | 0.2644 | |
Megaclite | meg'-ə-klye'-tee | 5 | 2.1E+14 | 24 687 240 | 792.436947 | 143.760° | 0.3078 | |
S/2003 J 2 | 2 | 1.5E+13 | 30 290 845 | 1077.018006 | 151.523° | 0.1882 | ? |
- (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) Computed from IAG Travaux 2001 for Metis through Callisto, IAU-MPC Satellites Ephemeris Service orbital elements for the others
Grouping the moons
The interior groups - the four inner moons and the Galileans - seem natural. Themisto is isolated in space. The 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. Carpo and S/2003 J 12 are two other isolated cases, and so is S/2003 J 2, the most exterior moon.
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. In the two plots below, Carme's group is in orange and Ananke's in yellow.
Image:Jupiter sats i vs a.png Image:Jupiter sats i vs e.png Image:Jupiter moons anim.gif 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.
Naming notes
Some asteroids share the same names as moons of Jupiter: 9 Metis, 38 Leda, 52 Europa, 85 Io, 113 Amalthea, 239 Adrastea.
A couple of asteroids shared the names of Jovian moons until spelling differences were made permanent by the IAU. Those contrasting pairs are the moon Ganymede and the asteroid 1036 Ganymed; and the moon Callisto and the asteroid 204 Kallisto. The moon Themisto purposely uses a name derived from the longer gentive form of the source of the name for asteroid 24 Themis.
Note that the satellites discovered between 1904 and 1951 (Himalia, Elara, Pasiphaë, Sinope, Lysithea, Carme and Ananke) were not officially named until 1975, 24 years after the last satellite was discovered. They were simply known by their Roman numeral designations (Jupiter VI through Jupiter XII). See Naming of natural satellites.
See also
- Saturn's natural satellites
- Uranus' natural satellites
- Neptune's natural satellites
- Pluto's natural satellites
External links
edit The Solar System |
---|
Planets: Mercury - Venus - Earth (Moon) - Mars - Jupiter - Saturn - Uranus - Neptune - Pluto |
Other: Sun - Asteroid belt - Main-belt comets - Kuiper belt - Scattered disc - Oort cloud |
See also astronomical objects and the solar system's list of objects, sorted by radius or mass. |
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