<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (December 2016) (Learn how and when to remove this template message) </Td> </Tr> <P> A rogue planet (also termed an interstellar planet, nomad planet, free - floating planet, orphan planet, wandering planet, starless planet, sunless planet, or Planemo) is a planetary - mass object that orbits the galaxy center directly . Such objects have either been ejected from the planetary system in which they formed or have never been gravitationally bound to any star or brown dwarf . The Milky Way alone may have billions of rogue planets . </P> <P> Some planetary - mass objects are thought to have formed in a similar way to stars, and the IAU has proposed that those objects be called sub-brown dwarfs . A possible example is Cha 110913 - 773444, which might have been ejected and become a rogue planet, or otherwise formed on its own to become a sub-brown dwarf . The closest free - floating planetary - mass object to Earth yet discovered, WISE 0855 − 0714, is at 7 light years, though it may be a sub-brown dwarf . </P> <P> Recent observations of a very young free - floating planetary - mass object, OTS 44, with the Herschel Space Observatory and the Very Large Telescope demonstrate that the processes that characterize the canonical star - like mode of formation apply to isolated objects down to a few Jupiter masses . Herschel far - infrared observations show that this young free - floating planetary - mass object is surrounded by a disk of at least 10 Earth masses, and thus eventually, can form a mini planetary system . Spectroscopic observations of OTS 44 with the SINFONI spectrograph at the Very Large Telescope reveal that the disk is actively accreting matter, in a similar way to young stars . In December 2013, a candidate exomoon of a rogue planet was announced . </P>

How many rogue planets are in our solar system