The Approach to Collapse of Molecular Clouds

Abstract

The dense molecular cloud cores that form stars, like other self-gravitating objects, undergo bulk oscillations. Just at the point of gravitational instability, their fundamental oscillation mode has zero frequency. We study, using perturbation theory, the evolution of a spherical cloud that possesses such a frozen mode. We find that the cloud undergoes a prolonged epoch of subsonic, accelerating contraction. This slow contraction occurs whether the cloud is initially inflated or compressed by the oscillation. The subsonic motion described here could underlie the spectral infall signature observed in many starless dense cores.

References in corpus (25)

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Cited by in corpus (6)

• Starless Cloud Core L1517B in Envelope Expansion with Core Collapse
• Molecular Line Profiles from Contracting Dense Cores
• Externally Fed Star Formation: A Numerical Study
• On the internal dynamics of starless cores: stability of starless cores with internal motions and collapse dynamics
• Dense Molecular Cores Being Externally Heated
• Externally Fed Accretion onto Protostars