Iocaste (moon)

Not to be confused with the minor planet named 899 Jokaste.

Iocaste

Iocaste imaged by the Canada-France-Hawaii Telescope in December 2001
Discovery [1]
Discovered by	Scott S. Sheppard David C. Jewitt Yanga R. Fernandez Eugene A. Magnier
Discovery site	Mauna Kea Observatory
Discovery date	23 November 2000
Designations
Designation	Jupiter XXIV
Pronunciation	/aɪoʊˈkæstiː/
Named after	Ιοκάστη Iokástē or Jocasta
Alternative names	S/2000 J 3
Adjectives	Iocastean /ˌaɪoʊkæˈstiːən/[2]
Orbital characteristics [3]
Epoch 17 December 2020 (JD 2459200.5)
Observation arc	17.39 yr (6,350 days)
Semi-major axis	0.1432617 AU (21,431,650 km)
Eccentricity	0.3294908
Orbital period (sidereal)	–640.97 d
Mean anomaly	289.50565°
Mean motion	0° 33^m 41.927^s / day
Inclination	149.42446° (to ecliptic)
Longitude of ascending node	343.53045°
Argument of perihelion	110.27239°
Satellite of	Jupiter
Group	Ananke group
Physical characteristics[4]
Mean diameter	5 km
Mean radius	1.6 miles (2.6 km)
Albedo	0.04 (assumed)
Apparent magnitude	21.8[5]
Absolute magnitude (H)	15.5[3]

Iocaste, also known as Jupiter XXIV, is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii including: David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier led by Scott S. Sheppard in 2000, and given the temporary designation S/2000 J 3.^[6][1]

Iocaste orbits Jupiter at an average distance of 20.723 million kilometers in 632 earth days, at an inclination of 147° to the ecliptic (146° to Jupiter's equator) with an eccentricity of 0.2874.

It was named in October 2002 after Jocasta,^[7] the mother/wife of Oedipus in Greek mythology. The name ending in "e" was chosen in accordance with the International Astronomical Union's policy for designating outer moons with retrograde orbits.

Iocaste belongs to the Ananke group, believed to be the remnants of a break-up of a captured heliocentric asteroid.^[8][9]

The satellite is about 5 kilometres in diameter^[10] and appears grey (colour indices B−V=0.63, R−V=0.36), similar to C-type asteroids.^[11]

See also

• Moons of Jupiter
• Praxidike

References

1. Brian G. Marsden (5 January 2001). "S/2000 J 2, S/2000 J 3, S/2000 J 4, S/2000 J 5, S/2000 J 6". International Astronomical Union Minor Planet Center.
2. Kin'ya Tsuruta (1996) Shiga Naoya's A Dark Night's Passing, p. 92
3. "M.P.C. 127087" (PDF). Minor Planet Circular. Minor Planet Center. 17 November 2020.
4. "Planetary Satellite Physical Parameters". Jet Propulsion Laboratory. 19 February 2015. Retrieved 26 November 2020.
5. Sheppard, Scott. "Scott S. Sheppard - Jupiter Moons". Department of Terrestrial Magnetism. Carnegie Institution for Science. Retrieved 26 November 2020.
6. Daniel W. E. Green (5 January 2001). "Satellites of Jupiter". International Astronomical Union Central Bureau for Astronomical Telegrams.
7. Daniel W. E. Green (22 October 2002). "Comet P/2002 T5 (Linear)". International Astronomical Union Central Bureau for Astronomical Telegrams.
8. Sheppard, S. S.; Jewitt, D. C.; "An Abundant Population of Small Irregular Satellites Around Jupiter" Archived August 13, 2006, at the Wayback Machine, Nature, Vol. 423 (May 2003), pp. 261–263
9. Nesvorný, D.; Alvarellos, J. L. A.; Dones, L.; and Levison, H. F.; "Orbital and Collisional Evolution of the Irregular Satellites", The Astronomical Journal, Vol. 126 (2003), pp. 398–429 ^{[dead link‍]}
10. Sheppard, S. S.; Jewitt, D. C.; Porco, C. C.; "Jupiter's Outer Satellites and Trojans" Archived June 14, 2007, at the Wayback Machine, in Jupiter: The Planet, Satellites and Magnetosphere, edited by Fran Bagenal, Timothy E. Dowling, and William B. McKinnon, Cambridge Planetary Science, Vol. 1, Cambridge, UK: Cambridge University Press, ISBN 0-521-81808-7, 2004, pp. 263–280
11. Grav, T.; Holman, M. J.; Gladman, B. J.; and Aksnes, K.; "Photometric survey of the irregular satellites", Icarus, Vol. 166 (2003), pp. 33–45

Further reading

• Ephemeris IAU-MPC NSES
• Mean orbital parameters NASA JPL