Lysithea (moon)

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Discovered by S. B. Nicholson
Discovery date July 6, 19381
Adjective Lysithean
Orbital characteristics
Mean orbit radius 11,720,000 km2
Eccentricity 0.112
Orbital period 259.20 d (0.69 a)2
Average orbital speed 3.29 km/s
Inclination 28.30° (to the ecliptic)
25.77° (to Jupiter's equator)2
Satellite of Jupiter
Physical characteristics
Mean radius 18 km3
Surface area ~4100 km²
Volume ~24,400 km³
Mass 6.3×1016 kg
Mean density 2.6 g/cm³ (assumed)3
Equatorial surface gravity ~0.013 m/s2 (0.001 g)
Escape velocity ~0.022 km/s
Albedo 0.04 (assumed)3
Temperature ~124 K

Lysithea (/lˈsɪθiə/ ly-SITH-ee-ə, /lɨˈsɪθiə/ li-SITH-ee-ə; Greek: Λυσιθέα) is a prograde irregular satellite of Jupiter. It was discovered by Seth Barnes Nicholson in 1938 at Mount Wilson Observatory1 and is named after the mythological Lysithea, daughter of Oceanus and one of Zeus' lovers.4

Lysithea didn't receive its present name until 1975; before then, it was simply known as Jupiter X. It was sometimes called "Demeter"5 from 1955 to 1975.

It belongs to the Himalia group, five moons orbiting between 11 and 13 Gm from Jupiter at an inclination of about 28.3°.2 Its orbital elements are as of January 2000. They are continuously changing due to solar and planetary perturbations.

See also


  1. ^ a b Nicholson, S.B. (1938). "Two New Satellites of Jupiter". Publications of the Astronomical Society of the Pacific 50: 292–293. Bibcode:1938PASP...50..292N. doi:10.1086/124963. 
  2. ^ a b c d e Jacobson, R.A. (2000). "The orbits of outer Jovian satellites". Astronomical Journal 120 (5): 2679–2686. Bibcode:2000AJ....120.2679J. doi:10.1086/316817. 
  3. ^ a b c "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 2008-10-24. Retrieved 2008-12-12. 
  4. ^ Marsden, B. G. (1974-10-07). "Satellites of Jupiter". IAUC Circular 2846. 
  5. ^ Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-13-478107-4. 

External links

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