Deborah & William Hillyard
Deborah & William Hillyard
Deborah & William Hillyard
Deborah & William Hillyard
Deborah & William Hillyard

Solar System -

Jupiter's Moons

Himalia Group

The Himalia Group of irregular moons comprises the following members: Leda, Himalia, Lysithea, Elara, and S/2000 J 11.  They all orbit Jupiter in a prograde direction at between 11.4 and 13 million kilometers radius, at around 27.5° to the plane of the ecliptic. 
Discovered in December 3rd, 2904, Himalia is believed to be between about 135 and 170 km across, making it the largest of Jupiter's irregular satellites.  In November 2000, Cassini approached to within 4.4 million km, and it appears that Himalia is elongated and about 150 ±20 km by 120 ±20 km.  It is also the heaviest after the four Galilean moons.  Himalia's orbit is eccentric varying between 9,782,900 and 13,082,000 km.  It takes 250.56 days to orbit Jupiter, and about 10 hours to rotate once on its axis.  To the right is a faint image of Himalia taken by the New Horizons spacecraft in 2007 from a distance of 5.5 million km. 
Lysithea was discovered 1938 at Mount Wilson Observatory.  On average, it is only about 36 km across, and orbits in a somewhat eccentric orbit at an average distance of about 11,720,000 km once every 259.2 days. 
Credit: NASA
Leda
Elara was discovered in 1905 at the Lick Observatory.  On average, it is about 86 km across, and orbits in an eccentric orbit at an average distance of about 11,740,000 km once every 259.64days. 
2000 J 11
Leda was discovered on September 14, 1974 at the Mount Palomar Observatory.  On average, it is only about 20 km across, and orbits in an eccentric orbit at an average distance of about 11,160,000 km once every 240.92 days.   
Himalia
Lysithea
Elara
Discovered in 2000, S/2000 J 11 is about 4 km in diameter, and orbits in an eccentric orbit at an average distance of 12,555,000 km once every 287 days.  Since then, it appears to have disappeared, and may have collided with Himalia.  In March 2010, NASA reported that a very faint new ring had been spotted by New Horizons that may be the result of this collision.  The ring had not been seen prior to 2003. 
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Jupiter's moons are grouped as follows.  Select to see details of the moon or the group of moons: