Lysithea (moon)

Lysithea /laɪˈsɪθiə/ is a prograde irregular satellite of Jupiter. It was discovered 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.[9]

Lysithea

Discovery
Discovered by	S. B. Nicholson
Discovery date	July 6, 1938[1]
Designations
Designation	Jupiter
Pronunciation	/laɪˈsɪθiə/[2][3]
Named after	Λυσιθέα Lysithea
Adjectives	Lysithean /laɪˈsɪθiən/[4]
Orbital characteristics [5]
Semi-major axis	11717000 km
Eccentricity	0.112
Orbital period	+259.2 days
Mean anomaly	329.1°
Inclination	28.30°
Longitude of ascending node	5.5°
Argument of perihelion	49.5°
Satellite of	Jupiter
Group	Himalia group
Physical characteristics
Mean diameter	42.2±0.7 km[6]
Mass	6.3×10^16 kg
Mean density	2.6 g/cm^3 (assumed)[7]
Rotation period	12.78±0.10 h[8]
Albedo	0.036±0.006[6]
Temperature	~124 K
Apparent magnitude	18.2

Lysithea did not receive its present name until 1975; before then, it was simply known as Jupiter X. It was sometimes called "Demeter"[10] 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°.[11] Its orbital elements are as of January 2000. They are continuously changing due to solar and planetary perturbations.

Lysithea observed by the Wide-field Infrared Survey Explorer (WISE) spacecraft in 2014

See also

• Irregular satellites
• Jupiter's moons in fiction

References

1. Nicholson, S. B. (October 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. "Lysithea". Dictionary.com Unabridged. Random House.
3. Cf. also 'Lysithous' in Noah Webster (1884) A Practical Dictionary of the English Language
4. Yenne (1987) The Atlas of the Solar System.
5. S.S. Sheppard (2019), Moons of Jupiter, Carnegie Science, on line
6. Grav, T.; Bauer, J. M.; Mainzer, A. K.; Masiero, J. R.; Nugent, C. R.; Cutri, R. M.; et al. (August 2015). "NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal. 809 (1): 9. Bibcode:2015ApJ...809....3G. doi:10.1088/0004-637X/809/1/3. 3.
7. "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). Retrieved December 12, 2008.
8. Luu, Jane (September 1991). "CCD photometry and spectroscopy of the outer Jovian satellites". Astronomical Journal. 102: 1213–1225. Bibcode:1991AJ....102.1213L. doi:10.1086/115949. ISSN 0004-6256.
9. Marsden, Brian G. (October 7, 1975). "Satellites of Jupiter". International Astronomical Union.
10. Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-13-478107-4.
11. Jacobson, R.A. (2000). "The orbits of outer Jovian satellites" (PDF). Astronomical Journal. 120 (5): 2679–2686. Bibcode:2000AJ....120.2679J. doi:10.1086/316817.

External links

• Lysithea: Overview by NASA's Solar System Exploration
• David Jewitt pages
• Jupiter's Known Satellites (by Scott S. Sheppard)