Himalia group

The Himalia group is a group of prograde non-spherical moons of Jupiter that follow similar orbits to Himalia and are thought to have a common origin.

The known members of the group are (in order from closest to farthest from Jupiter):
 Leda
 Himalia (the biggest, which gives its name to the group)
 Lysithea
 Elara
The orbit estimate of the recently found moon S/2000 J 11 also qualified it as a member of the group (it appeared to have the same inclination, and a slightly bigger semi-major axis)Scott S. Sheppard, David C. Jewitt
An abundant population of small irregular satellites around Jupiter, Nature, 423 (May 2003), pp.261-263 
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but its orbit is not known exactly and the mean orbital elements have not yet been calculated.

The International Astronomical Union (IAU) reserves names in -a for the moons in this group.

Characteristics and origin

The objects in the Himalia group have semi-major axes (distances from Jupiter) in the range of 11,150,000 and 11,750,000 km, inclinations between 26.6° and 28.3°, and eccentricities of between 0.11 and 0.25.
All moons in the group are grey similar to C-type asteroids. It has been suggested that the group could be a remnant of the break-up of an asteroid from the main asteroid belt.Grav, Tommy; Holman, Matthew J.; Gladman, Brett J.; Aksnes, Kaare Photometric survey of the irregular satellites, Icarus, 166,(2003), pp. 33-45. Preprint The radius of the parent asteroid was probably about 89 km, only a bit bigger than that of Himalia, which retains approximately 87% of the mass of the original body. This indicates the asteroid was not heavily disturbed.

References

Category:Jupiter's moons