Elara (moon)

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Categories: Jupiter's moons | Irregular satellites

**Elara**
Discovery
Discovered by	C. D. Perrine
Discovery date	January 2, 1905^[1]^[2]
Orbital characteristics
Mean orbit radius	11,740,00 km (0.07810 AU)^[4]
Eccentricity	0.22^[4]
Orbital period	259.64 d (0.708 a)^[4]
Average orbital speed	3.27 km/s^[4]
Inclination	26.63° (to the ecliptic) 30.66° (to Jupiter's equator)^[4]
Satellite of	Jupiter
Physical characteristics
Mean radius	43 km
Surface area	~23,200 km²
Volume	~333,000 km³
Mass	8.7×10¹⁷ kg
Mean density	2.6 g/cm³ (assumed)
Equatorial surface gravity	~0.031 m/s² (0.003 g)
Escape velocity	~0.052 km/s
Sidereal rotation period	~0.5 d (12 h)
Albedo	0.04 (assumed)
Temperature	~124 K

Elara (el'-ər-ə, IPA: /ˈɛlərə/; Greek Ελάρα) is a prograde irregular satellite of Jupiter. It was discovered by Charles Dillon Perrine at Lick Observatory in 1905^[1]^[2] and is named after the mother by Zeus of the giant Tityus.^[5]

Elara did not receive its present name until 1975; before then, it was simply known as Jupiter VII. It was sometimes called "Hera"^[6] between 1955 and 1975.

Elara belongs to the Himalia group, five moons orbiting between 11 and 13 Gm from Jupiter at an inclination of about 27.5°.^[4] Its orbital elements are as of January 2000. They are continuously changing due to Solar and planetary perturbations.

1 New Horizons encounter
2 See also
3 References
4 External links

New Horizons encounter

In February and March 2007, the New Horizons spacecraft to Pluto made a number of images of Elara, culminating in photos from a distance of five million miles.

References

^ ^a ^b Perrine, C. D. (1905 February 27). "Satellites of Jupiter". Harvard College Observatory Bulletin 178.
^ ^a ^b Perrine, C. D. (1905). "The Seventh Satellite of Jupiter". Publications of the Astronomical Society of the Pacific 17 (101): 62–63.
^ [1]
^ ^a ^b ^c ^d ^e ^f Jacobson, R. A. (2000). "The orbits of outer Jovian satellites". Astronomical Journal 120: 2679-2686. doi:10.1086/316817.
^ Marsden, B. G. (7 October 1974). "Satellites of Jupiter". IAUC Circular 2846.
^ Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-134-78107-4.

External links

v • d • e

Moons of Jupiter

Listed in increasing distance from Jupiter. Temporary names in italics.

Inner moons

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

core	Ananke · Praxidike · Harpalyke · Iocaste · Euanthe · Thyone
peripheral	Euporie · S/2003 J 3 · S/2003 J 18 · Thelxinoe · Helike · Orthosie · S/2003 J 16 · Hermippe · Mneme · S/2003 J 15

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