A simulation of the collapse and fragmentation of cooling molecular clouds

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We describe the application of the Smoothed Particle Hydrodynamics method to the fragmentation of rotating cloud and disk systems, allowing for molecular cooling due to H2 and CO. We also describe a novel approach to solving Poisson's equation for disklike structures, which exploits the multigrid algorithm. Numerical studies are presented which investigate the evolution of both rotating clouds and Maclaurin disks, in each case with both an isothermal equation of state and with molecular cooling. Our results establish the influence of molecular cooling on the fragmentation of molecular clouds. The isothermal sequences, if they fragment at all, do so into far fewer lumps than the cooling sequences. This is not due to a cooling instability as such, but rather to the reduced thermal support. One of our sequences shows a remarkable similarity to the W49A star-forming region.

Original languageEnglish
Pages (from-to)177-189
Number of pages13
JournalThe Astrophysical Journal
Issue number1
Publication statusPublished - 1 Jul 1991


  • Hydrodynamics
  • Interstellar: molecules
  • Nebulae: individual (W49)
  • Nebulae: structure

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