Amalthea (moon)

Edward E. Barnard

Amalthea ( Jupiter V) is one of the inner moons of Jupiter.


The moon was discovered on September 9, 1892 by the astronomer Edward E. Barnard at the 91- cm refractor of the Lick Observatory. He was the fifth moon of Jupiter discovered by the Erstbeobachtung of the four Galilean moons in 1610. Moreover, he was the last moon, which was discovered by visual telescopic observations. All subsequent moon finds access based photographic recordings.

It was named after the nymph Amalthea from Greek mythology, who nursed Zeus with goat's milk. The name " Amalthea ", which goes back to a proposal by the French astronomer Camille Flammarion, was approved by the International Astronomical Union ( IAU) officially awarded until 1975, although he was unofficially in use for decades. The moon was usually referred to simply as "Jupiter V " Before 1975.

Structure and physical data

Amalthea is a very irregularly shaped body with an area of ​​270 km × 168 km × 150 km, the longitudinal axis being directed to Jupiter. The density is very low at 0.86 g/cm3; that speaks for a porous structure of water ice. Maybe it is a " stray" object that comes either from the outer Jovian system or created on a large distance from the Sun and has been captured by Jupiter's gravitational influence.

Amalthea has a very dark, deep red colored surface with an albedo of 0.09; This means that only 9% of the incoming sunlight will be reflected. The red color may be due to deposits of sulfur, which was thrown from the moon Io by volcanic eruptions in space. In addition, bright greenish patterns are visible, whose origin is still unknown.

The surface is heavily cratered. Some of the craters are very large compared to Amalthea's size. The largest crater pan has a diameter of 100 km and 8 km deep. The crater Gaea has a diameter of 90 km and is probably 16 km deep. Two mountain ranges, Mons and Mons Ida facula, approximately 20 km collect.

Amalthea rotates in 11 hours and 57 minutes around its own axis, thus showing how the Earth's Moon and the other inner moons of Jupiter, a tidally locked to.

The apparent magnitude is 14.1 m.

As Io, Amalthea is more heat than the body receives from the Sun. This could be due to electric currents that are induced by Jupiter's magnetic field during the motion of the moons.

Pictures of Amalthea (moon)