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Classification Of Jupiters Moons
There were initially
four groups It used to be thought that Jupiter's
moons were arranged neatly into four groups
of four, but recent discoveries of many
new small outer moons have complicated the
division; there are now thought to be six
main groups, although some are more distinct
than others. |
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Europa , one of Jupiter's many moons.
X
The inner groups of four small moons all have diameters of
less than 200 km, orbit at radii less than 200,000 km, and
have orbital inclinations of less than half a degree.
X The
four Galilean moons were all found by Galileo Galilei , orbit
between 400,000 and 2,000,000 km, and include some of the
largest moons in the solar system.
X Themisto
is in a group of its own, and it orbits halfway between the
Galilean moons and the next group.
X The
Himalia group is a tightly clustered group of moons with orbits
around 11-12,000,000 km from Jupiter.
X Carpo
is another isolated case; at the inner edge of the Ananke
group, it revolves in the direct sense.
X
The Ananke group is a collection with rather indistinct borders,
averaging 21,276,000 km from Jupiter with an average inclination
of 149 degrees.
X The
Carme group is a fairly distinct group that averages 23,404,000
km from Jupiter with an average inclination of 165 degrees.
X
The Pasiphae group is a dispersed and only vaguely distinct
group that covers all the outermost moons.
It is thought that the groups of smaller moons
may each have a common origin, perhaps as a larger
moon or captured body that broke up into the existing
moons of each group.
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