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Structure and Evolution of the Envelopes of Deeply Embedded Massive Young Stars

  • van der Tak, Floris F. S.
  • van Dishoeck, Ewine F.
  • Evans, Neal J.
  • Blake, Geoffrey A.
Published Article
Publication Date
Feb 01, 2000
Submission Date
Jan 31, 2000
DOI: 10.1086/309011
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The physical structure of the envelopes around a sample of fourteen massive (1000-100,000 solar L) young stars is investigated on 100- 100,000 AU scales using maps and spectra in submillimeter continuum and lines of C17O, CS and H2CO. The total column densities and the temperature profiles are obtained by fitting self-consistent dust models to submillimeter photometry. Both the molecular line and dust emission data indicate density gradients ~r^{-alpha}, with alpha=1.0-1.5, significantly flatter than the alpha=2.0 generally found for low-mass objects. This flattening may indicate that in massive young stellar objects, nonthermal pressure is more important for the support against gravitational collapse, while thermal pressure dominates for low-mass sources. We find alpha=2 for two hot core-type sources, but regard this as an upper limit since in these objects, the CS abundance may be enhanced in the warm gas close to the star.


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