Jupiter's satellites

(redirected from Moons of Jupiter)
Also found in: Wikipedia.

Jupiter's satellites

(Jovian satellites) A system of diverse satellites orbiting Jupiter at distances between 128 000 km and 24 million km and ranging in size from the planet-like Galilean satellites to tiny worlds of rock and ice measuring barely 1 kilometer across. At the end of 2004, 63 Jovian satellites were known, most of which were discovered after 2000 through analysis of photographs taken either by spacecraft such as the Voyager probes or Galileo mission or by high-quality groundbased instruments using large-format CCDs. Their physical and orbital properties are given in Table 2, backmatter.

The satellites can be divided into three main groups. The largest is an outer group of at least 48 small bodies moving in loosely bound retrograde orbits (see direct motion) that are highly eccentric and are inclined to Jupiter's equatorial plane by an angle of about 150°–160°; most of them orbit the planet in periods of about 700 days and at mean distances of roughly 21 to 24 million km. Chief among them are Ananke, Carme, Pasiphae, and Sinope. The most remote one of this group so far known, designated S/2003 J2, in fact orbits Jupiter in more than 900 days at a mean distance of more than 28 million km. An intermediate group of five small satellites (Leda, Himalia, Lysithea, Elara, and S/2000 J11) move in approximately 250-day direct orbits at mean orbital distances between 11 and 12 million km; the orbits are generally less eccentric than those of the outer group and are inclined at an angle of about 28° to Jupiter's equatorial plane. Two other satellites follow direct orbits that do not fit neatly into either the outer or intermediate groups. These are Themisto, which orbits Jupiter in 130 days at a mean distance of about 7 million km and with an inclination of 43°, and S/2003 J20, which completes an orbit every 456 days at a mean distance of 17 million km and an inclination of 51°. The inner group is comprised of the four large Galilean satellitesIo, Europa, Ganymede, and Callisto – together with Amalthea and the three satellites Thebe, Adrastea, and Metis; these all move in near-circular direct orbits that lie close to the plane of Jupiter's equator.

The members of the outer and intermediate groups are probably captured asteroids, although the capturing process that would place objects into one group rather than the other has not been defined. Possibly some of them were former members of the Trojan group of asteroids. All eight inner satellites are believed to have formed out of the dust particles that surrounded the disk of gas and dust from which Jupiter formed. These inner satellites all lie within Jupiter's magnetosphere and are effective in sweeping up the charged particles found there, becoming intensely radioactive in the process.

Metis, Jupiter's innermost satellite, was unknown before Voyager 2 photographed it in 1979. So too were Thebe and Adrastea. The irregularly shaped Amalthea had been discovered in 1892, but few details of it were known before the visit of the Voyager probes. The Galilean satellites, however, have been studied throughout the telescopic era but came under much more intensive scrutiny from Pioneer 10 and 11, as well as the Voyager and Galileo missions.

References in periodicals archive ?
They are the four largest moons of Jupiter Io, Europa, Ganymede, and Callisto," Yelk said.
Summary: TEHRAN (FNA)- Using Earth's most powerful array of radio telescopes, astronomers have made the first observations of a circumplanetary disk of gas and dust like the one that is believed to have birthed the moons of Jupiter.
This includes the moons of Jupiter and Saturn, as well as our own Moon.
Which of these moons of Jupiter is the largest: Europa; Himalia; Callisto; Io?
ON JULY 17TH, the IAU's Minor Planet Center announced that a search team led by Scott Sheppard (Carnegie Institution for Science) has identified 10 new moons of Jupiter, bringing the known total to 79--the most of any planet in our solar system.
They all turned out to be moons of Jupiter. The confirmation of 10 was announced Tuesday.
In a surprise discovery, a team of researchers stumbled upon 12 more moons of Jupiter, the biggest and one of the most famous planets in our Solar System.
The Galilean moons of Jupiter are named after the lovers of which Greek god?
Scientists at NASA believe that some of the moons of Jupiter may be habitable celestial objects with the abundance of water; therefore, they don't want a foreign object from Planet Earth to land in a moon while spreading earthly-germs in them, threatening the alien existence.
Researchers suspect that several moons of Jupiter and Saturn harbor subterranean seas.
The icy moons of Jupiter and Saturn, such as Europa and Enceladus, are likely to have undergone cometary bombardment.
Spacecraft have snapped pictures of impact craters on Mercury, Venus and many of the moons of Jupiter, Saturn and Uranus (see slideshow below).