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Posted on 3 Oct. 2018
"These distant objects are like crumbs of bread that lead us to Planet X," said Scott Sheppard of the Carnegie Institution for Sciences. "The more we find, the better we can understand the outer solar system and the planet that we think shapes their orbits – a discovery that would redefine our understanding of the evolution of the solar system."
Astronomers have discovered a new object at the edge of our solar system. The new extremely distant object, well beyond Pluto, has an orbit that supports the presence of a larger planet X. The object was discovered as part of the ongoing hunting of the team looking unknown dwarf planets and planet X. distant objects of the solar system.
The goblin is a recently confirmed dwarf planet that moves to the confines of the solar system. Known officially as the TG387 2015, the nickname comes from the "TG" part of the designation and the fact that it was first seen around Halloween in 2015, according to the Carnegie Institution for Science.
The discovery was made by Sheppard, Chad Trujillo from the University of Northern Arizona and David Tholen from the Institute of Astronomy at the University of Hawaii.
2015 TG387, announced by the Center of the Minor Planet of the International Astronomical Union, was discovered at about 80 astronomical units (AU) of the sun. An AU is the distance between the Earth and the Sun. For contextual reasons, the Pluto distance is about 34 AU; the TG387 2015 is about two and a half times more distant from the sun than Pluto.
"We think that there could be thousands of small bodies like the TG387 2015 at the periphery of the solar system, but their distance makes their search very difficult," Tholen said. "Currently, we would only detect the TG387 2015 when it is getting closer to its closest approach to the sun. For some 99% of its 40,000 years of orbit, it would be too weak to see it, even with today's largest telescopes. "
Tholen first observed the 2015 TG387 in October 2015 at the 8-meter Subaru Japanese Telescope in Maunakea, Hawaii. The team's software detected the object in unusual motion, which caused Tholen to more accurately measure the position of the object and to orient it to other telescopes for further observations.
It took a few years of observations to the team to get a good orbit for 2015T G387 as it was moving slowly, in a big orbit, so it had a very long orbital period. Tracking observations at the Magellan telescope at the Carnegie Observatory of Las Campanas in Chile and the Discovery Channel Telescope in Arizona were obtained in 2015, 2016, 2017 and 2018 to measure the 2015 TG387 orbit.
With these data in hand, they determined that the new found object was in a very elongated orbit and that the closest point of it to the sun, a point called perihelion, was about 65 AU. . Only the 2012 VP113 and Sedna, at 80 and 76 UA respectively, have a more distant perihelion than the 2015 TG387. Although 2015 TG387 has the third most distant perihelion, its orbital semi-major axis is larger than the 2012 VP113 and Sedna, which means that it moves much farther from the Sun than they do. At its furthest point, it reaches about 2,300 AU. 2015 TG387 is one of the few known objects to never get close enough to the giant planets of the solar system, such as Neptune and Jupiter, to have meaningful gravitational interactions with them.
"These objects called Inner Oort Cloud such as 2015 TG387, 2012 VP113 and Sedna are isolated from most of the known mass of the solar system, which makes them extremely interesting," Sheppard explained. "They can be used as probes to understand what is happening at the edge of our solar system."
The object with the most distant orbit at perihelion, 2012 VP113, was also discovered by Sheppard and Trujillo in 2014. The discovery of 2012, VP113, led Sheppard and Trujillo to see similarities between orbits of several objects of the solar system extremely far away. the presence of an unknown planet several times larger than Earth – sometimes called Planet X – orbiting the Sun, far beyond Pluto, to hundreds of AU.
2015 TG387 is probably a dwarf planet, since it has a diameter of about 300 km. The location in the sky where 2015 TG387 reaches perihelion is similar to VP113, Sedna, and most other well-known trans-Neptunian objects, suggesting that something is dragging them into different types. similar orbits.
Nathan Kaib of Trujillo and the University of Oklahoma conducted computer simulations to determine the impact of different hypothetical orbits on Planet X in the 2015 TG387 orbit. The simulations included a super-terrestrial planet with several hundred AU in an elongated orbit, proposed by Caltech's Konstantin Batygin and Michael Brown in 2016, based on previous work by Sheppard and Trujillo.
Most of the simulations showed that not only was the TG387's 2015 orbit stable for the age of the solar system, but it was actually guided by the gravity of Planet X, which keeps the 2015 TG387 smaller in size. away from the planet. This gravitational incentive could explain why the objects furthest from our solar system have similar orbits. These orbits prevent them from getting too close to the proposed planet, as Pluto never gets too close to Neptune, even if their orbits intersect.
"What makes this result really interesting is that Planet X seems to affect 2015 TG387 in the same way as all the other extremely distant objects in the solar system. These simulations do not prove that there is another gigantic planet in our solar system, but they provide further evidence that something might be great, "Trujillo concludes.
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