Planet Ten is a hypothetical body in the solar system said to be beyond the eighth planet Neptune and the demoted Pluto. It is theorized to be either around the mass and size of Mars or Earth and lies at the edge of the Kuiper Belt[1]. Like Planet Nine, we haven't confirmed the existence of Planet Ten as of now. It is possibly responsible for the existence of the "Kuiper Cliff" which is located at around 50 AU from our star, the Kuiper Cliff is an area where the Kuiper Belt seems to cut off like there's an unknown body picking up material from it, hence the Planet Ten theory.[2]
Some might call it "Planet Nine" due to it being nearer to the sun than the actual Planet Nine.
Possible Satellites/Moons[]
Planet Ten may have a lot of possible moons, as it could pick up a lot from the Kuiper Cliff. Due to the Kuiper Cliff having icy objects, it can have icy moons.
Name[]
Similar to Planet Nine, Planet Ten would not receive a proper name until its existence has been confirmed. via imaging and such. as for the reasons mentioned on Planet Nine's page, the IAU will certify a name, with the priority being given to a name proposed by Planet Ten's possible discoverers. of course, that likely means that Planet Ten would receive a name hailing from Greek or Roman mythology, if its existence has been confirmed.