Planet X
Planet X : In 2016 further work showed this unknown distant planet is likely on an inclined, eccentric orbit that goes no closer than about 200 AU and no further than about 1600 AU from the Sun. The orbit is predicted to be anti-aligned to the clustered extreme trans-Neptunian objects. Because Pluto is no longer considered a planet by the International Astronomical Union, this new hypothetical object has become known as Planet Nine.
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