The Magellan telescope in Chile captured these recovery images of the oddball Jovian moon, known as Valetudo, in May.
Why are we just now hearing about it? Sheppard said. "That is what we are trying to answer".
It has an angled prograde orbit that takes about a year and a half to complete. He has also been involved in the discovery of 25 of Saturn's known moons, two moons around Uranus and one orbiting Neptune, two comets, and over a dozen minor planets, which includes the farthest known object of the solar system - 2012 VP113(nicknamed Biden). Those 2017 moons were labeled S/2016 J1 and S/2017 J1.
The astronomers were looking for objects on the fringes of the solar system when they spotted the Jupiter moons. It is also likely Jupiter's smallest known moon, being less than one kilometre [0.6 miles] in diameter'. The researchers think these moons are also fragmented remnants of larger moons broken apart after colliding with another body.
If they had formed earlier, the influence of gas and dust would have created drag and caused them to spiral inward to the planet, lost forever.
Nine of the new moons belong to an outer "retrograde" swarm circling against the direction of Jupiter's rotation. Nine objects, which are in three different groups, are likely the remnants of larger moons that broke apart during collisions. The orbits of the new moons are marked with thicker curves. It is more distant (for good reason!), more inclined, takes longer to orbit Jupiter than its siblings, and crosses the outer retrograde moons.
12 new moons spotted around Jupiter - but one may destroy them all
It's been nicknamed Valetudo after the Roman goddess of health and hygiene who is the great-granddaughter of the god Jupiter.
The orbits of the twelve newly discovered moons of Jupiter are shown here in bold.
This moon, now called Valetudo, moves in a prograde motion, though it is slightly inclined compared to the orbits of the other moons.
A head-on collision between two moons would "grind the objects down to dust", he added. And in fact all the groups of shattered retrograde objects do lend credence to this idea. It would be like driving down a highway going the wrong way. Even so, it's a bit of a surprise to see that this week astronomers announced finding an even dozen more moons orbiting the king of the planets!
Jupiter's family has really grown since Galileo first recorded its four largest moons in 1610.
The oddball moon, along with two other new moon discoveries, orbit in the prograde, or same direction as the planet's rotation. One moon detected by Sheppard and his colleagues is the smallest Jovian moon ever discovered. It was probably forming in the giant planet region and grew to be several Earth masses in size, and then it got close to one of the giant planets and was thrown out into the outer solar system. So hey, why not look for some more moons? We actually found, on some of the best nights we had, we could image objects even deeper - things that are right on the edge of our noise. It's just very hard to follow those. For the other 11 moons, Sheppard said they might let the public help out.
Putin summit: USA leader cautious ahead of Helsinki talks
The US president also renewed accusations that the European Union was taking advantage of the United States in trade. Trump and Putin have held talks several times before.
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