The Inevitable Future of the Starless Core Barnard 68

Abstract

Dense, small molecular cloud cores have been identified as the direct progenitors of stars. One of the best studied examples is Barnard 68 which is considered a prototype stable, spherical gas core, confined by a diffuse high-pressure environment. Observations of its radial density structure however indicate that Barnard 68 should be gravitationally unstable and collapsing which appears to be inconsistent with its inferred long lifetime and stability. We argue that Barnard 68 is currently experiencing a fatal collision with another small core which will lead to gravitational collapse. Despite the fact that this system is still in an early phase of interaction, our numerical simulations imply that the future gravitational collapse is already detectable in the outer surface density structure of the globule which mimicks the profile of a gravitationally unstable Bonnor-Ebert sphere. Within the next 200,000 years Barnard 68 will condense into a low-mass solar-type star(s), formed in isolation, and surrounded by diffuse, hot interstellar gas. As witnessed in situ for Barnard 68, core mergers might in general play an important role in triggering star formation and shaping the molecular core mass distribution and by that also the stellar initial mass function.

7 pages, 6 figures, submitted to ApJ

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Cited by in corpus (15)

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• Implementation of Sink Particles in the Athena Code
• The Dependence of Star Formation Efficiency on Gas Surface Density
• Observation of rotation in star forming regions: clouds, cores, disks, and jets
• Turbulence, Coherence and Collapse: Three Phases for Core Evolution
• Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. II. Varied Shock Wave and Cloud Core Parameters
• First Investigation of the Combined Impact of Ionizing Radiation and Momentum Winds from a Massive Star on a Self-Gravitating Core
• From Filaments to Oscillating Starless Cores
• The HP2 Survey - IV. The Pipe nebula: Effective dust temperatures in dense cores
• Prestellar Cores in Turbulent Clouds: Numerical Modeling and Evolution to Collapse
• Formation of accretion centers in simulations of colliding uniform density H${}_2$ cores
• On the interaction of a Bonnor-Ebert sphere with a stellar wind
• The future of low-mass condensations in a core of molecular cloud
• Simulations of un-equal binary collisions embedded in a turbulent gas cloud far away of a massive gravitational center