Researchers Discover a Star's Minimum Possible Mass

paulmac84 writes "Stars that don't have enough mass never shine, dying billions of years before their bigger counterparts. But astronomers have never been able to measure the exact mass limit, because the lightest stars that do shine can be simply too faint to detect. Now, new images show for the first time how big a star must be to avoid impending doom. The long-awaited new images finally lay this question to rest, say the authors. The dimmest stars were measured as being 8.3% of the Sun's mass. All protostars that are smaller than this are headed for life as a brown dwarf."

Comments

For those who are wondering...

[Anonymous Coward]

... that's 87 Jupiters.

Re:Finally a Definitive Answer!

[cswiger2005]

If there were dimmer stars present there, the Hubble's main camera would have been sensitive enough to have seen them...they're pretty sure of this because they were able to notice some very dim white dwarfs (a white dwarf is the remenant stellar core of a bigger star which went nova; they are very hot [initally] but also very tiny), which are dimmer than the smallest M-class stars still in the main sequence.

Basicly, this observation is in reasonably close accordance with the theories about stellar fusion; basicly, an potential star needs to have about ten or fifteen times Jupiter's mass before deuterium fusion is possible, and about 70 times Jupiter's mass before normal hydrogen fusion happens (according to the models).

Jupiter weighs 1.899 * 10^29kg; Sol weighs 1.989 * 10^32 kg (or about 1050 times what Jupiter weighs).
8.4% of Sol's mass is 1.65 * 10^30, or 87 times what Jupiter weighs.