Himalia (moon)
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| Discovery | |||||||
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| Discovered by | C. D. Perrine | ||||||
| Discovered on | December 3, 1904 | ||||||
| Orbital characteristics | |||||||
| Mean radius | 11,432,430 km (0.07642 AU) | ||||||
| Eccentricity | 0.1443 | ||||||
| Periapsis | 9,782,900 km (0.065 AU) | ||||||
| Apoapsis | 13,082,000 km (0.087 AU) | ||||||
| Orbital period | 249.726 d (0.704 a) | ||||||
| Orbital circumference | 71,456,750 km (0.478 AU) | ||||||
| Orbital velocity | max: 3.850 km/s mean: 3.312 km/s min: 2.879 km/s |
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| Inclination | 29.88° (to the ecliptic) 29.59° (to Jupiter's equator) |
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| Is a satellite of | Jupiter | ||||||
| Physical characteristics | |||||||
| Mean diameter | 170 km | ||||||
| Surface area | ~90,800 km2 | ||||||
| Volume | ~2,570,000 km3 | ||||||
| Mass | 6.7×1018 kg | ||||||
| Mean density | 2.6 g/cm3 | ||||||
| Surface gravity | ~0.062 m/s2 (0.006 g) | ||||||
| Escape velocity | ~0.100 km/s | ||||||
| Rotation period | ~0.4 d (10 h) | ||||||
| Axial tilt | ?° | ||||||
| Albedo | 0.04 | ||||||
| Surface temp. |
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| Atmospheric pressure | 0 kPa | ||||||
Himalia (hye-mal'-ee-ə, also hi-mahl'-ee-ə, IPA: [haɪˈmæliə, hɪˈmɑliə]; 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
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.[2]
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.[3] Measurements by Cassini confirm the featureless spectrum, with a slight absorption at 3 μm which could indicate the presence of water.[4]
[edit] See also
[edit] External links
[edit] References
- ^ Astronomical Journal, 24 (1905), 154B [1]
- ^ Carolyn C. Porco et al. Cassini Imaging of Jupiter's Atmosphere, Satellites, and Rings , Science, 299(March 2003), pp. 1541 - 1547.
- ^ 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.
 edit Jupiter's natural satellites |
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| Inner satellites | Galilean moons | Themisto | Himalia group | Carpo | S/2003 J 12 | Ananke group | Carme group | Pasiphaë group | S/2003 J 2 |
| See also: Pronunciation key | Rings of Jupiter |
