Description
A rogue planet (also termed a free-floating planet (FFP) , isolated planetary-mass object (iPMO) , interstellar , nomad , orphan , starless , unbound or wandering planet ) is an interstellar object of planetary mass which is not gravitationally bound to any star or brown dwarf. Rogue planets may originate from planetary systems in which they are formed and later ejected, or they can also form on their own, outside a planetary system. The Milky Way alone may have billions to trillions of rogue planets, a range the upcoming Nancy Grace Roman Space Telescope will likely be able to narrow down.
Some planetary-mass objects may have formed in a similar way to stars, and the International Astronomical Union has proposed that such objects be called sub- brown dwarfs. A possible example is Cha 110913−773444, which may have been ejected and become a rogue planet, or formed on its own to become a sub-brown dwarf.
