Lysithea (moon)

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Lysithea
Discovery
Discovered by S. B. Nicholson
Discovery time July 6, 1938[1]
Names
Adjective Lysithean
Orbit
Avgdistance from the center of its orbital path 11,720,000 km[2]
How egg-shaped its orbit is
("eccentricity")
0.11[2]
How long it takes to complete an orbit 259.20 d (0.69 a)[2]
Average speed 3.29 km/s
Angle above the reference plane
("inclination")
28.30° (to the ecliptic)
25.77° (to Jupiter's equator)[2]
What it orbits Jupiter
Size and Other Qualities
Average distance from its center to its surface 18 km[3]
Area of its surface ~4100 km²
Volume inside it ~24,400 km³
Mass 6.3×1016 kg
Average density 2.6 g/cm³ (assumed)[3]
Gravity at its surface ~0.013 m/s2 (0.001 g)
Slowest speed able to escape into space
("escape velocity")
~0.022 km/s
How much light it reflects 0.04 (assumed)[3]
Avg. surface temp. ~124 K

Lysithea (/lˈsɪθiə/ ly-SITH-ee-ə, /lɨˈsɪθiə/ li-SITH-ee-ə; Greek: Λυσιθέα) is a prograde non-spherical moon of Jupiter. It was found by Seth Barnes Nicholson in 1938 at Mount Wilson Observatory[1] and is named after the mythological Lysithea, daughter of Oceanus and one of Zeus' lovers.[4]

Lysithea did not get 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 11,000,000 and 13,000,000 km from Jupiter at an inclination of about 28.3°.[2] Its orbital elements are as of January 2000. They are changing a lot due to Solar and planetary perturbations.

References[change | change source]

  1. 1.0 1.1 Nicholson, S. B. (1938). "Two New Satellites of Jupiter". Publications of the Astronomical Society of the Pacific 50: 292–293. http://adsabs.harvard.edu//full/seri/PASP./0050//0000292.000.html.
  2. 2.0 2.1 2.2 2.3 2.4 Jacobson, R. A. (2000). "The orbits of outer Jovian satellites". Astronomical Journal 120: 2679-2686. doi:10.1086/316817.
  3. 3.0 3.1 3.2 "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 2008-10-24. http://ssd.jpl.nasa.gov/?sat_phys_par. Retrieved 2008-12-12.
  4. Marsden, B. G. (7 October 1974). "Satellites of Jupiter". IAUC Circular 2846. http://cfa-www.harvard.edu/iauc/02800/02846.html.
  5. Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-134-78107-4.

Other websites[change | change source]