Turbulence in Class 0 and I protostellar envelopes |
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| Authors: | D Ward-Thompson L Hartmann D J Nutter |
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| Institution: | Department of Physics and Astronomy, Cardiff University, Cardiff CF24 3YB;Harvard-Smithsonian Centre for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA |
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| Abstract: | We estimate the levels of turbulence in the envelopes of class 0 and I protostars using a model based on measurements of the peak separation of double-peaked asymmetric line profiles. We use observations of 20 protostars of both class 0 and I taken in the HCO+(J = 3 → 2) line that show the classic double-peaked profile. We find that some class 0 sources show high levels of turbulence, whilst others demonstrate much lower levels. In class I protostars, we find predominantly low levels of turbulence. The observations are consistent with a scenario in which class 0 protostars form in a variety of environments and subsequently evolve into class I protostars. The data do not appear to be consistent with a recently proposed scenario in which class 0 protostars can only form in extreme environments. |
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| Keywords: | radiative transfer stars: formation ISM: clouds submillimetre |
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