Planet Foramtion without stars

[TShock]

has anyone ever done research on the accretion of planets into a system without a star forming? Just a dark system. How likely is this to happen as opposed to a system forming with a star?

[g33kski11z]

..what would the planets orbit?

[Borek]

Central body can be massive, but it can be not massive enough to become a star. Like a brown dwarf (check wikipedia article). See also wiki entry on Cha 110913-773444.

Borek
--
http://www.chembuddy.com
http://www.ph-meter.info

[Chronos]

As Borek noted, planet formation does not require a star. An oversized 'Jupiter' would be sufficient. I expect any such planets would, however, be small.

[g33kski11z]

"David Bennett of the University of Notre Dame has discovered an extra-solar planet of about three Earth masses orbiting a star with a mass so low that its core may not be large enough to maintain nuclear reactions"

I noticed this on Science Daily this morning.

http://www.sciencedaily.com/releases/2008/06/080602131105.htm

[Orion1]

A rogue planet is an object which has equivalent mass to a planet and is not gravitationally bound to any star, and that therefore moves through space as an independent object.

Sub-brown dwarf is a planetary-mass object whose mass is smaller than the low-mass cut-off for brown dwarfs (around 13 times the mass of Jupiter). Unlike proper brown dwarfs, they are not massive enough to fuse deuterium. Sub-brown dwarfs are formed in the manner of stars, through the collapse of a gas cloud, and not through accretion or core collapse from a circumstellar disc.

Reference:
Interstellar planet - Wikipedia (http://en.wikipedia.org/wiki/Interstellar_planet)
Sub-brown dwarf - Wikipedia (http://en.wikipedia.org/wiki/Sub-brown_dwarf)