Iocaste, also known as , is a retrograde

irregular satellite In astronomy, an irregular moon, irregular satellite, or irregular natural satellite is a natural satellite following an orbit that is irregular in some of the following ways: Distant; inclined; highly elliptical; retrograde. They have often be ...

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

. It was discovered by a team of astronomers from the

University of Hawaii A university () is an educational institution, institution of tertiary education and research which awards academic degrees in several Discipline (academia), academic disciplines. ''University'' is derived from the Latin phrase , which roughly ...

including: David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier led by Scott S. Sheppard in 2000, and given the temporary designation . Iocaste orbits Jupiter at an average distance of 20.723 million kilometers in 632 earth days, at an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 147° to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

(146° to Jupiter's equator) with an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.2874. It was named in October 2002 after

Jocasta In Greek mythology, Jocasta (), also rendered as Iocaste ( ) and EpicasteHomer, ''Odyssey'', Vol. XI11.271/ref> (; ), was Queen of Thebes through her marriages to Laius and her son, Oedipus. She is best known for her role in the myths surroundi ...

, the mother/wife of

Oedipus Oedipus (, ; "swollen foot") was a mythical Greek king of Thebes. A tragic hero in Greek mythology, Oedipus fulfilled a prophecy that he would end up killing his father and marrying his mother, thereby bringing disaster to his city and family. ...

Greek mythology Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories conc ...

. 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.Sheppard, S. S.; Jewitt, D. C.
"An Abundant Population of Small Irregular Satellites Around Jupiter"
, ''Nature,'' Vol. 423 (May 2003), pp. 261–263 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 The satellite is about 5 kilometres in diameterSheppard, S. S.; Jewitt, D. C.; Porco, C. C.
"Jupiter's Outer Satellites and Trojans"
, 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, , 2004, pp. 263–280 and appears grey ( colour indices B−V=0.63, R−V=0.36), similar to

C-type asteroid C-type (carbonaceous ) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...

s. Grav, T.; Holman, M. J.; Gladman, B. J.; and Aksnes, K.
"Photometric survey of the irregular satellites"
''Icarus'', Vol. 166 (2003), pp. 33–45

See also

References

Further reading