Astronomers say they've spotted lonesome planet without a sun

[MicaelS]

30. The term usually used is "Rogue Planet".

http://en.wikipedia.org/wiki/Rogue_planet

also known as an interstellar planet, nomad planet, free-floating planet or orphan planet

A rogue planet — also known as an interstellar planet, nomad planet, free-floating planet or orphan planet — is a planetary-mass object which has either been ejected from its system or was never gravitationally bound to any star, brown dwarf or other such object, and that therefore orbits the galaxy directly. Astronomers agree that either way, the definition of planet should depend on its current observable state and not its origin.

Larger planetary-mass objects which were not ejected, but have always been free-floating, are thought to have formed in a similar way to stars, and the IAU has proposed that those objects be called sub-brown dwarfs (an example of this is Cha 110913-773444, which may be an ejected rogue planet or may have formed on its own and be a sub-brown dwarf).The closest rogue planet to Earth yet discovered, PSO_J318.5-22, is around 80 light years away.

The subject is fascinating, and I'm glad to see more attention being paid to this subject.