Astronomers Serendipitously Discover 12 Moons Around Jupiter

  • Astronomers Serendipitously Discover 12 Moons Around Jupiter

Astronomers Serendipitously Discover 12 Moons Around Jupiter

A research team led by astronomer Scott Sheppard of the Carnegie Institution for Science in Washington has identified 12 small Jovian moons, including the 10 described on Tuesday. That brings its total known satellites to 79, the most in the solar system.

The new moons, pictured as circles above, were discovered previous year by a team of astronomers. After verification, they are being reported today by the International Astronomical Union, based in Paris.

"Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant Solar System objects, so we were serendipitously able to look for new moons around Jupiter while at the same time looking for planets at the fringes of our Solar System", Sheppard said in a Carnegie press release.

Of the 79 moons now known, most orbit in the same direction as other moons nearest them.

The newly discovered moons await naming, a task for which the public may be enlisted, so it's a good idea to brush up on the IAU's naming rules for Jovian moons - and which names have already been taken. Valetudo orbits Jupiter in the same direction that the planet spins, but a bunch of other small moons share the same orbital path while travelling in the opposite direction.

Astronomers have proposed the name "Valetudo" for the oddball moon, after the Roman god Jupiter's great-granddaughter, the goddess of health and hygiene. Many of Jupiter's outer moons were likely formed by collisions between larger retrograde moons and oddball prograde satellites.

Astronomers spotted the new moons while looking for a possible massive planet beyond Pluto.

Jupiter, the fifth planet from the Sun, has a diameter of 142,984km.

In addition to these two groups, Jupiter has "regular" satellites, or moons with almost circular orbits.

Maybe we need something similar for tiny moons. If small moons like these were around when the solar system was still thick with gas and dust, drag forces would have slowed them down and caused them to fall into Jupiter, never to be seen again.

For example, the discovery that the smallest moons in Jupiter's various orbital groups are still abundant suggests the collisions that created them occurred after the era of planet formation. Each is only one to three kilometres wide, and thus would be very hard to spot using most telescopes.

It takes around 18 months to orbit Jupiter, and its orbit passes that of the retrograde moons, which makes collisions pretty likely. Two of the newly discovered moons, the ones closest to Jupiter, have prograde orbits, too.

In the meantime, "we have to speculate about what they [the new moons] are made of", Sheppard said.

Two more of the moons are in a group that circle much closer to the planet in prograde orbits which travel in the same direction as Jupiter's spin. Sheppard expects there could be even more small moons lurking out there. "New cameras allow us to cover the whole space around Jupiter in a few images, and this camera is well-shaded", Sheppard said.

Valetudo is something of an oddball. They could be rock, ice or a mixture.

"If we do find this planet in the next few years, it would be a pretty wonderful discovery for astronomy". "The only thing that we know at the moment are the orbits and the approximate size", Williams said.