One 'Oddball' Among 12 Newfound Moons Discovered Orbiting Jupiter

Mindy Sparks
July 17, 2018

One of the new moons in the outer group is particularly unique, according to astronomer Scott Sheppard at the Carnegie Institution for Science, who led the team that first spotted the moons previous year.

Astronomers searching for a planet beyond Pluto discovered instead a dozen new moons orbiting Jupiter. That brings its total known satellites to 79, the most in the solar system.

A research team from the Carnegie Institution for Science, the University of Hawaii and Northern Arizona University was looking in 2017 for very distant objects in our solar system, well beyond Pluto.

"We're looking for new possible planets and dwarf planets in our solar system, just seeing what is out there", Sheppard said.

Gareth Williams, an astronomer at the Harvard-Smithsonian Center for Astrophysics and director at the International Astronomical Union's Minor Planet Center, predicted that "there aren't any bigger objects undiscovered out there" around Jupiter. And after follow-up observations, they've confirmed that Jupiter has even more moons than we thought. While the team did discover 12 new moons, two were announced a year ago.

Nine of the newly discovered moons have retrograde orbits, meaning that they orbit in the opposite direction of the planet's spin. They are thought to be the remnants of larger parent bodies that were broken apart in collisions with asteroids, comets and other moons.

A look at Jupiter's new moons.

The moon, which has the proposed name Valetudo, orbits in the same direction as Jupiter's rotation, unlike all the other moons in the outer group. And these new moons point to a violent and destructive past.

"Our other discovery is a real oddball and has an orbit like no other known Jovian moon", Sheppard said.


Jupiter's moons are sort of like opposite lanes on a highway. "It's also likely Jupiter's smallest known moon, being less than one kilometer in diameter".

"With the discovery of Valetudo, it seems the collisions that broke apart the retrograde moons were between other prograde Jupiter moons, like Valetudo", Sheppard told ScienceAlert.

"This is an unstable situation", said Sheppard.

A greater number of irregular moons because it tells us about a time during Jupiter's formation when the planet was still growing. "Valetudo" - after the great-granddaughter of the Roman god Jupiter - also known as the goddess of health and hygiene.

Elucidating the complex influences that shaped a moon's orbital history can teach scientists about our Solar System's early years. While the scientists' planet hunt has so far come up dry, the team, using the recently upgraded Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile, also had Jupiter in view, leading to the discovery.

The moons are too small to see with the average telescope - measuring only a few kilometers in size. If these raw materials had still been present when Jupiter's first generation of moons collided to form its current clustered groupings of moons, the drag exerted by any remaining gas and dust on the smaller moons would have been sufficient to cause them to spiral inwards toward Jupiter.

Finding a moon that tiny, he noted, means it must have formed after all the gas and dust had cleared.

Of the 12 newly discovered moons, 11 are "normal, "according to a statement from the Carnegie Institution for Science". It took one of the most powerful digital cameras in the world - the Dark Energy Camera - to spot them. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions.

Other reports by Iphone Fresh

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