Astronomy

A Stellar Future Ahead?

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Science  01 May 2009:
Vol. 324, Issue 5927, pp. 568
DOI: 10.1126/science.324_568a
CREDIT: ESO

Barnard 68 is a dark molecular cloud about 400 light years away from Earth. It contains mostly molecular hydrogen mixed with other molecules and dust grains in such high concentrations as to render it completely opaque at optical wavelengths. Stars are thought to be born in dark, cold places such as this. Yet Barnard 28 is still starless; before a star can form within the core, it needs to contract under the force of gravity for a period sufficient to ignite nuclear fusion. There is contradictory evidence as to whether Barnard 68 is still stable or already in a very early phase of gravitational collapse. Burkert and Alves now argue that Barnard 68, far from being a stable, isolated molecular cloud, is colliding with another, smaller cloud, as suggested by its asymmetric and distorted shape. Their numerical simulations of the collision imply that signs of an impending gravitational collapse can already be seen in Barnard 68, and the cloud should condense into a Sun-like star within the next 200,000 years.

Astrophys. J. 695, 1308 (2009).

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