More news about “Planet Nine” #Planet9

From BBC:

Case made for ‘ninth planet’

Artist's impression of ninth planet

Image copyright Caltech/R. Hurt (IPAC). Artist’s impression of a ninthe planet: Telescopes are sure to try to track down the object… if it really exists

American astronomers say they have strong evidence that there is a ninth planet in our Solar System orbiting far beyond even the dwarf world Pluto.

The team, from the California Institute of Technology (Caltech), has no direct observations to confirm its presence just yet.

Rather, the scientists make the claim based on the way other far-flung objects are seen to move.

But if proven, the putative planet would have 10 times the mass of Earth.

The Caltech astronomers have a vague idea where it ought to be on the sky, and their work is sure to fire a campaign to try to track it down.

“There are many telescopes on the Earth that actually have a chance of being able to find it,” said Dr Mike Brown.

“And I’m really hoping that as we announce this, people start a worldwide search to go find this ninth planet.”

Strange swing

The group’s calculations suggest the object orbits 20 times farther from the Sun on average than does the eighth – and currently outermost – planet, Neptune, which moves about 4.5 billion km from our star.

But unlike the near-circular paths traced by the main planets, this novel object would be in a highly elliptical trajectory, taking between 10,000 and 20,000 years to complete one full lap around the Sun.

The Caltech group has analysed the movements of objects in a band of far-off icy material known as the Kuiper Belt. It is in this band that Pluto resides.

The scientists say they see distinct alignments among some members of the Kuiper Belt – and in particular two of its larger members known as Sedna and 2012 VP113. These alignments, they argue, are best explained by the existence of a hitherto unidentified large planet.

“The most distant objects all swing out in one direction in a very strange way that shouldn’t happen, and we realised the only way we could get them to swing in one direction is if there is a massive planet, also very distant in the Solar System, keeping them in place while they all go around the Sun,” explained Dr Brown.

“I went from trying very hard to be sceptical that what we were talking about was true, to suddenly thinking, ‘this might actually be true’.”


The ‘ninth planet’ – where to look?

Orbital behaviour

Image copyright Caltech/R. Hurt (IPAC)

The six most distant known objects in the Solar System with orbits exclusively beyond Neptune (magenta) all line up in a single direction. Why? Drs Brown and Batygin argue that this is because a massive planet (orange) is anti-aligned with these objects. Can telescopes now find this planet? Could the evidence already be in observational data but no-one has yet recognised it? The hunt is on.


The idea that there might be a so-called Planet X moving in the distant reaches of the Solar System has been debated for more than a hundred years. It has fallen in and out of vogue.

What makes this claim a little more interesting is Dr Brown himself.

He specialises in finding far-flung objects, and it was his discovery of 2,236km-wide Eris in the Kuiper Belt in 2005 that led famously to the demotion of Pluto from full planet status a year later (Dr Brown’s Twitter handle is @PlutoKiller).

At that stage, Pluto was thought to be slightly smaller than Eris, but is now known to be just a little bit bigger.

Others who model the outer Solar System have been saying for some years that the distribution of sizes seen in the objects so far identified in the Kuiper Belt suggests another planet perhaps the size of Earth or Mars could be a possibility. But there is sure to be strong scepticism until a confirmed observation is made.

Nasa’s chief scientist, Ellen Stofan, said she certainly needed telescopic evidence.

“The intriguing point is: we’ve identified lots of planets (beyond our Solar System) in this category of ‘super-Earth’ with our Kepler telescope; over 5,000 planet candidates. The fact that we don’t have a planet in that size class between Earth and Neptune makes us think, ‘well, maybe we are missing one’, and maybe they’ve predicted it,” she told BBC News.

Dr Brown and Dr Konstantin Batygin (@kbatygin) report their work in The Astronomical Journal.

A new planet in our solar system? Introducing Planet Nine!

No, not Pluto. Two scientists from CalTech announced today that there is evidence for a new 9th planet, about the size of Neptune. This planet is thought to orbit the sun every 15,000 years. From Science:

The claim is the strongest yet in the centuries-long search for a “Planet X” beyond Neptune. The quest has been plagued by far-fetched claims and even outright quackery. But the new evidence comes from a pair of respected planetary scientists, Konstantin Batygin and Mike Brown of the California Institute of Technology (Caltech) in Pasadena, who prepared for the inevitable skepticism with detailed analyses of the orbits of other distant objects and months of computer simulations. 

Mike Brown (left) and Konstantin Batygin.

Mike Brown (left) and Konstantin Batygin.

LANCE HAYASHIDA/CALTECH

Outside scientists say their calculations stack up and express a mixture of caution and excitement about the result. “I could not imagine a bigger deal if—and of course that’s a boldface ‘if’—if it turns out to be right,” says Gregory Laughlin, a planetary scientist at the University of California (UC), Santa Cruz. “What’s thrilling about it is [the planet] is detectable.”

Batygin and Brown inferred its presence from the peculiar clustering of six previously known objects that orbit beyond Neptune. They say there’s only a 0.007% chance, or about one in 15,000, that the clustering could be a coincidence. Instead, they say, a planet with the mass of 10 Earths has shepherded the six objects into their strange elliptical orbits, tilted out of the plane of the solar system.

The orbit of the inferred planet is similarly tilted, as well as stretched to distances that will explode previous conceptions of the solar system. Its closest approach to the sun is seven times farther than Neptune, or 200 astronomical units (AUs). (An AU is the distance between Earth and the sun, about 150 million kilometers.) And Planet X could roam as far as 600 to 1200 AU, well beyond the Kuiper belt, the region of small icy worlds that begins at Neptune’s edge about 30 AU.

If Planet X is out there, Brown and Batygin say, astronomers ought to find more objects in telltale orbits, shaped by the pull of the hidden giant. But Brown knows that no one will really believe in the discovery until Planet X itself appears within a telescope viewfinder. “Until there’s a direct detection, it’s a hypothesis—even a potentially very good hypothesis,” he says. The team has time on the one large telescope in Hawaii that is suited for the search, and they hope other astronomers will join in the hunt.

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