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 a distant, inclined, and often eccentric and retrograde orbit. They have been captured by their parent planet, unlike regular s ...

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

. It was discovered by a team of astronomers from the

University of Hawaii A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...

including: David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier led by

Scott S. Sheppard Scott Sander Sheppard (born 1977) is an American astronomer and a discoverer of numerous moons, comets and minor planets in the outer Solar System. He is an astronomer in the Department of Terrestrial Magnetism at the Carnegie Institution for Scie ...

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 the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic agains ...

(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, the mother/wife of Oedipus in

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the lives and activities ...

. 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