On Tue, 20 Feb 2007 17:21:22 +0000, jimhigh66 wrote:

(I've never heard this discussed.)
Could systems form where the center mass is insufficient to start a
nuclear reaction? If so any idea how prevalent they might be? Have any
such systems ever been observed (by infrared emissions or a pecular
spectra)? Might they be part of "dark matter" ? Jim H.

If you are thinking of a brown dwarf with a planetary system, see
Sincell M, Science 2001, 292: 1984-85. Protoplanetary disk has been
discovered around brown dwarfs.

--
gautam