Formation of stellar clusters in magnetized, filamentary infrared dark clouds

Journal Article · 18 November 2017 · Monthly Notices of the Royal Astronomical Society

DOI: https://doi.org/10.1093/mnras/stx2611 · OSTI ID:1523826

Li, Pak Shing ^[1]; Klein, Richard I. ^[2]; McKee, Christopher F. ^[1]

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1. Univ. of California, Berkeley, CA (United States)
2. Univ. of California, Berkeley, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Star formation in a filamentary infrared dark cloud (IRDC) is simulated over the dynamic range of 4.2 pc to 28 au for a period of 3.5 × 10⁵ yr, including magnetic fields and both radiative and outflow feedback from the protostars. At the end of the simulation, the star formation efficiency is 4.3 per cent and the star formation rate per free-fall time is ε_ff ≃ 0.04, within the range of observed values. The total stellar mass increases as ~t², whereas the number of protostars increases as ~t^1.5. We postulate that the density profile around most of the simulated protostars is ~ρ ∝ r^-1.5. At the end of the simulation, the protostellar mass function approaches the Chabrier stellar initial mass function. We infer that the time to form a star of median mass 0.2 M_⊙ is about 1.4 × 10⁵ yr from the median mass accretion rate. We find good consensus among the protostellar luminosities observed in the large sample of Dunham et al., our simulation and a theoretical estimate, and we conclude that the classical protostellar luminosity problem is resolved. The multiplicity of the stellar systems in the simulation agrees, to within a factor of 2, with observations of Class I young stellar objects; most of the simulated multiple systems are unbound. Bipolar protostellar outflows are launched using a subgrid model, and extend up to 1 pc from their host star. The mass–velocity relation of the simulated outflows is consistent with both observation and theory.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC52-07NA27344; AC02-05CH11231
• OSTI ID: 1523826
• Journal Information: Monthly Notices of the Royal Astronomical Society, Vol. 473, Issue 3; ISSN 0035-8711
• Publisher: Royal Astronomical SocietyCopyright Statement
• Country of Publication: United States
• Language: English