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

Lysithea in a 2MASS photograph
Discovery [1]
Discovered by	Seth B. Nicholson
Discovery site	Mt. Wilson Observatory
Discovery date	6 July 1938
Designations
Designation	Jupiter X
Pronunciation	/laɪˈsɪθiə/[2][3]
Named after	Λυσιθέα Lysithea
Adjectives	Lysithean /laɪˈsɪθiən/[4]
Orbital characteristics [5]
Epoch 27 April 2019 (JD 2458600.5)
Observation arc	79.87 yr (29,171 days)
Semi-major axis	0.0782144 AU (11,700,710 km)
Eccentricity	0.1478734
Orbital period	+258.57 d
Mean anomaly	27.18992°
Mean motion	1° 23^m 32.227^s / day
Inclination	26.29254° (to ecliptic)
Longitude of ascending node	343.46495°
Argument of perihelion	94.80010°
Satellite of	Jupiter
Group	Himalia group
Physical characteristics
Mean diameter	42.2±0.7 km[6]
Rotation period	12.78±0.10 h[7]
Albedo	0.036±0.006[6]
Apparent magnitude	18.2[8]
Absolute magnitude (H)	11.2[5]

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 (297): 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. "M.P.C. 115890" (PDF). Minor Planet Circular. Minor Planet Center. 27 August 2019.
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" (PDF). The Astrophysical Journal. 809 (1): 9. Bibcode:2015ApJ...809....3G. doi:10.1088/0004-637X/809/1/3. S2CID 5834661. 3.
7. 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.
8. Sheppard, Scott. "Scott S. Sheppard - Jupiter Moons". Department of Terrestrial Magnetism. Carnegie Institution for Science. Retrieved 26 November 2020.
9. Marsden, Brian G. (7 October 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)