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Scientists have discovered another marker on the track towards the so-called Planet Nine.
This index is 2015 TG387, a new object discovered in the outdoor solar system, far beyond Pluto. The 2015 TG387 orbit shares some peculiarities with those of other extremely distant bodies, which seem to have been shaped by the gravity of a very large object in this far-flung and icy realm – the hypothesis Planet Nine, also known as Planet X.
"These distant objects are like crumbs of bread that take us to Planet X," said Scott Sheppard, head of the study, from the Carnegie Institution for Science in Washington, DC, in a statement. [The Evidence for ‘Planet Nine’ in Our Solar System (Gallery)]
"The more we find, the better we can understand the outer solar system and the possible planet that we believe is shaping their orbits – a discovery that would redefine our understanding of the evolution of the solar system," he added. .
And 2015 TG387 is special among these breadcrumbs, as it was found during a relatively uniform survey of northern and southern skies rather than a targeted hunt for clustered objects in some parts of the world. heaven, said Sheppard. Targeted hunts can produce biased results – for example, clustering where there may not be one, he explained.
Sheppard said: TG387 2015 has two companions of the dwarf planet in the low-bias class: VP113 2012, which he and his colleague Chadwick Trujillo (who is also co-author of the new paper) spotted in 2014 as part of the same ongoing long-term survey; and the Sedna relatively bright (because all the sky was searched at its level of brightness).
"And then, if you bring some of the other extreme objects, many of them have also been found in our investigation," Sheppard told Space.com. "The statistics are improving more and more, according to which this planet is probably there"
Images from the TG387 2015 discovery taken at the 8-meter Subaru telescope at the top of Mauna Kea in Hawaii on October 13, 2015. Images were taken approximately 3 hours apart. We can see 2015 TG387 moving between images near the center, while stars and galaxies much farther away are motionless.
Credit: Scott Sheppard
Sheppard and her colleagues first discovered the 2015 TG387 in October 2015, using the 8-foot Subaru Japanese Telescope located atop the Mauna Kea Volcanic Peak in Hawaii. The researchers nicknamed the object "The goblin", because of the date of discovery and the "TG" in the provisional designation.
Three more years were needed for the team to fix the goblin's orbit, thanks to observations from the Las Campanas Observatory in Chile and the Discovery Channel telescope in Arizona.
2015 TG387 loops around the sun on an extremely elliptical path, lying at about 65 astronomical units (AU) from the sun to its nearest point (called perihelion) and standing at about 2,300 AU at its furthest distance (aphelion) ).
An AU is the average Sun-Earth distance – about 150 million miles (150 million kilometers). 2015 TG387 is a solution, a solution. Indeed, it takes about 40 000 Earth years for the new object found to complete a tour of the sun. [Our Solar System: A Photo Tour of the Planets]
Only two known bodies of the solar system have more peripheral outlying areas than the Goblin (2012 VP113 and Sedna), and only one (2014 FE72) has a greater distance of aphelion. (For perspective: Plutonever is closer to the sun than 29.7 AU, or farther than 49.3 AU.)
The orbits of the new extreme dwarf planet 2015 TG387 and its other objects Inner Oort Cloud 2012 VP113 and Sedna, compared to the rest of the solar system.
Credit: Roberto Molar Candanosa and Scott Sheppard, courtesy of Carnegie Institution for Science
Sheppard and her colleagues think that the 2015 TG387 is about 300 km wide and that it's probably spherical. In this case, it would be called a dwarf planet. But that's all they can really say about the physical characteristics of Goblin.
"It's pretty weak, so we can really see that it's there," Sheppard told Space.com. "We do not even know the color of the object, we have not yet got spectroscopy, or anything like that."
(The 186-mile diameter is not a measurement but rather an estimate, assuming a "moderate" reflectivity for 2015 TG387.)
But back to the orbit: that of Goblin is similar to that of some other extremely distant bodies, especially in an element called "longitude of perihelion". Basically, the elongated parts of their elliptical orbits are grouped in the same part of the sky, which is compatible with the gravitational shepherd of planet X.
The existence of Planet X was seriously proposed for the first time in 2014 by Sheppard and Trujillo, potentially to explain the strange orbits of 2012, VP113, Sedna and some other trans-Neptunian objects.
In 2016, astronomers Konstantin Batygin and Mike Brown presented more evidence of such a "disrupt", which they called Planet Nine. Batygin and Brown have suggested that this world would be about 10 times larger than the Earth and gravitate around 600 AU of the average sun.
Illustration by an artist of the supposed but undiscovered Planet X, which could shape the orbits of more distant objects of the outermost solar system such as 2015 TG387.
Credit: Roberto Molar Candanosa and Scott Sheppard, courtesy of Carnegie Institution for Science
In the new study, researchers also conducted computer simulations to test the impact of Planet X's gravity tug on the Goblin's orbit. They discovered that the shepherd was similar to the one that had been deduced for other distant objects – and determined that the 2015 TG387 orbit was still stable for the solar system age.
"What makes this result really interesting, is that Planet X seems to affect 2015 TG387 in the same way as all other extremely distant objects in the solar system," said Trujillo, based at Northern Arizona University, in the same release. prove that there is another massive planet in our solar system, but they are further proof that something big could be out there. "
Sheppard estimates that the probability of planet X being around 85%. And he says that it's not at all surprising that astronomers have not seen it yet.
"Where we think the planet is – at hundreds of AU's, if it's 1,000 AU -, something as big as Neptune would be weaker than most telescopes could see, "Sheppard told Space.com. (If it sounds strange or incongruous to you: the goblin was found near perihelion, about 80 AU from the sun.)
"And most of our investigations so far are not going so badly, do not go that far, we have very little covered the sky to the depth that we have to cover to find something so weak" , he added. "You can very easily hide a very big thing in the external solar system."
The document describing the discovery of 2015 TG387 has been submitted to The Astronomical Journal.
Follow Mike Wall on Twitter @michaeldwall and Google+. follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.
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