Himalia (moon)
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| Discovery | |
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| Discovered by: | C. D. Perrine |
| Discovery date: | December 3, 1904 |
| Orbital characteristics | |
| Periapsis: | 9,782,900 km (0.065 AU) |
| Apoapsis: | 13,082,000 km (0.087 AU) |
| Mean radius of orbit: | 11,432,430 km (0.07642 AU) |
| Orbital circumference: | 71,456,750 km (0.478 AU) |
| Eccentricity: | 0.1443 |
| Orbital period: | 249.726 d (0.704 a) |
| Avg. orbital speed: | 3.312 km/s |
| Max. orbital speed: | 3.850 km/s |
| Min. orbital speed: | 2.879 km/s |
| Inclination: | 29.88° (to the ecliptic) 29.59° (to Jupiter's equator) |
| Satellite of: | Jupiter |
| Physical characteristics | |
| Mean radius: | 85 km |
| Surface area: | ~90,800 km2 |
| Volume: | ~2,570,000 km3 |
| Mass: | 6.7×1018 kg |
| Mean density: | 2.6 g/cm3 |
| Equatorial surface gravity: | ~0.062 m/s2 (0.006 g) |
| Escape velocity: | ~0.100 km/s |
| Sidereal rotation period: | ~0.4 d (10 h) |
| Albedo: | 0.04 |
| Temperature: | ~124 K |
Himalia (IPA: [haɪˈmeɪ.li.ə], IPA: [hɪˈmɑ.li.ə]; Greek Ἱμαλíα) is the largest irregular satellite of Jupiter. It was discovered by Charles Dillon Perrine at the Lick Observatory in 1904[1] and is named after the nymph, Himalia who bore three sons of Zeus.
On December 19, 2000, the Cassini spacecraft, en route to Saturn, captured a very low resolution image of Himalia, but it was too distant to show any surface details.
Himalia did not receive its present name until 1975; before then, it was simply known as Jupiter VI. It was sometimes called "Hestia".
It is the largest member of the group that bears its name, the moons orbiting between 11.4 and 13 million kilometers from Jupiter at an inclination of about 27.5°.
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[edit] Physical characteristics
Himalia appears neutral (grey), as the other members of its group, with colour indices B-V=0.62, V-R= 0.4, similar to a C-type asteroid.[2] Measurements by Cassini confirm the featureless spectrum, with a slight absorption at 3 μm which could indicate the presense of water.[3]
[edit] Cassini encounter
Cassini pictured Himalia from 4.4 million km as an elongated object with axes 150 ± 20 and 120 ± 20 km, close to the Earth-based estimations.[4]
[edit] New Horizons Encounter
In February and March 2007, the New Horizons spacecraft to Pluto made a number of images of Himalia, culminating in photos from a distance of five million miles.
[edit] See also
[edit] External links
[edit] References
- ^ Astronomical Journal, 24 (1905), 154B [1]
- ^ Rettig, Terrence W.; Walsh, Kevin; Consolmagno, Guy Implied Evolutionary Differences of the Jovian Irregular Satellites from a BVR Color Survey, Icarus, 154, pp. 313-320 (2001)
- ^ Chamberlain, Matthew A.; Brown, Robert H. Near-infrared spectroscopy of Himalia, Icarus, 172 (2004), pp. 163-169.
- ^ Carolyn C. Porco et al. Cassini Imaging of Jupiter's Atmosphere, Satellites, and Rings , Science, 299(March 2003), pp. 1541 - 1547.
| Moons of Jupiter | |
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Listed in increasing distance from Jupiter. Italics indicate ungrouped moons.
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| Amalthea group | Metis · Adrastea · Amalthea · Thebe |
| Galilean moons | Io · Europa · Ganymede · Callisto |
| Themisto | |
| Himalia group | Leda · Himalia · Lysithea · Elara · S/2000 J 11 |
| Carpo · S/2003 J 12 | |
| Ananke group | Ananke · Praxidike · Harpalyke · Iocaste · Euanthe · Thyone (core) Euporie · S/2003 J 3 · S/2003 J 18 · Thelxinoe · Helike · Orthosie · S/2003 J 16 · Hermippe · Mneme · S/2003 J 15 (peripheral) |
| Carme group | S/2003 J 17 · S/2003 J 10 · Pasithee · Chaldene · Arche · Isonoe · Erinome · Kale · Aitne · Taygete · S/2003 J 9 · Carme · S/2003 J 5 · S/2003 J 19 · Kalyke · Eukelade · Kallichore |
| Pasiphaë group | Eurydome · S/2003 J 23 · Hegemone · Pasiphaë · Sponde · Cyllene · Megaclite · S/2003 J 4 · Callirrhoe · Sinope · Autonoe · Aoede · Kore |
| S/2003 J 2 | |
