Possible dwarf planet: celestial body with extreme orbit behind Neptune found

A research team from the USA has discovered 2017 OF₂₀₁, an extreme celestial body at the edge of the solar system, which suggests that there could be many more that cannot currently be discovered. The Institute for Advanced Study (IAS) has made this public and declared that 2017 OF₂₀₁, with a diameter of 700 km, could be large enough to be recognized as a dwarf planet. The orbit in which the object orbits the sun is also a challenge for theories that postulate a large ninth planet at the edge of the solar system, the team also writes.

Not detectable on most of the orbit

As Sihao Cheng's team explains, the closest point to the Sun (perihelion) of the orbit of 2017 OF₂₀₁ is about 44.5 astronomical units (AU) away from our home star, which is about the distance between Pluto and the Sun. However, the furthest point from the sun (aphelion) is therefore 1600 AU and the celestial body requires around 25,000 Earth years for one orbit. Only during one percent of this orbit is 2017 OF₂₀₁ close enough to us to be detectable with current technology. This suggests that there are still around 100 similar objects out there that cannot currently be found. So there is still a lot to discover at the edge of the solar system.

The possible dwarf planet was discovered in images taken by the Victor M. Blanco Telescope and the Canada France Hawaii Telescope with the help of a newly developed algorithm, the team writes. The discovery has significant consequences for the understanding of those areas in the solar system behind the orbit of Neptune. Until now, it had been assumed that although the Kuiper Belt exists there, it is “essentially empty” behind it. The discovery now suggests that this is not the case. Instead, there could be around 100 other objects that are similar in size and orbit to 2017 OF₂₀₁.

The extreme orbit of the celestial body indicates that it had a close contact with a gas giant in the solar system behind it, during which it was thrown into orbit, the team says. It could even have taken several steps for the celestial body to reach its current orbit. At the same time, however, it does not match a number of other so-called trans-Neptunian objects. Their grouping was considered an indication that a large ninth planet was still hiding out there. The fact that the orbit of 2017 OF₂₀₁ does not match this could speak against the hypothesis. The discovery is presented in a research article made available in advance.

(mho)