The Inevitable Future of the Starless Core Barnard 68 - AstrophysicsReport as inadecuate

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Abstract: Dense, small molecular cloud cores have been identified as the directprogenitors of stars. One of the best studied examples is Barnard 68 which isconsidered a prototype stable, spherical gas core, confined by a diffusehigh-pressure environment. Observations of its radial density structure howeverindicate that Barnard 68 should be gravitationally unstable and collapsingwhich appears to be inconsistent with its inferred long lifetime and stability.We argue that Barnard 68 is currently experiencing a fatal collision withanother small core which will lead to gravitational collapse. Despite the factthat this system is still in an early phase of interaction, our numericalsimulations imply that the future gravitational collapse is already detectablein the outer surface density structure of the globule which mimicks the profileof a gravitationally unstable Bonnor-Ebert sphere. Within the next 200,000years Barnard 68 will condense into a low-mass solar-type stars, formed inisolation, and surrounded by diffuse, hot interstellar gas. As witnessed insitu for Barnard 68, core mergers might in general play an important role intriggering star formation and shaping the molecular core mass distribution andby that also the stellar initial mass function.

Author: Andreas Burkert Munich, Joao Alves Calar Alto Obs.


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