Fragmentation in molecular clouds and its connection to the IMF

2009/03/18 by Rowan J. Smith, Paul C. Clark, I. A. Bonnell +1 · 87 citations
Chemical Engineering · Physics and Astronomy · #Accretion (finance) #Advanced Combustion Engine Technologies #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Core (optical fiber) #Fragmentation (computing) #Galaxies: Formation, Evolution, Phenomena #Initial mass function #Mass segregation #Molecular cloud #Physics #Star cluster #Star formation #Stars #Substructure #astro-ph.GA

paper · pdf · doi:10.1111/j.1365-2966.2009.14794.x

published in Monthly Notices of the Royal Astronomical Society 396(2), 830-841 (Oxford University Press) · 12 pages, 12 figures and 3 tables. Accepted by MNRAS

arxiv created 2009/03/18 · openalex publication_date 2009/05/13 · arxiv updated 2015/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We present an analysis of star-forming gas cores in a smooth particle hydrodynamics simulation of a giant molecular cloud. We identify cores using their deep potential wells. This yields a smoother distribution with clearer boundaries than density. Additionally, this gives an indication of future collapse, as bound potential cores (p-cores) represent the earliest stages of fragmentation in molecular clouds. We find that the mass function of the p-cores resembles the stellar initial mass function and the observed clump mass function, although p-core masses (∼0.7 M⊙) are smaller than typical density clumps. The bound p-cores are generally subsonic, have internal substructure and are only quasi-spherical. We see no evidence of massive bound cores supported by turbulence. We trace the evolution of the p-cores forward in time, and investigate the connection between the original p-core mass and the stellar mass that formed from it. We find that there is a poor correlation, with considerable scatter suggesting accretion on to the core is dependent on more factors than just the initial core mass. During the accretion process the p-cores accrete from beyond the region first bound, highlighting the importance of the core environment to its subsequent evolution.

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