Vibrationally excited HCN around AFGL 2591: A probe of protostellar structure

Todd J. Veach, Christopher Groppi, Abigail Hedden

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Vibrationally excited molecules with submillimeter rotational transitions are potentially excellent probes of physical conditions near protostars. This study uses observations of the v = 1 and v = 2 ro-vibrational modes of HCN (4-3) to probe this environment. The presence or absence and relative strengths of these ro-vibrational lines probe the gas excitation mechanism and physical conditions in warm, dense material associated with protostellar disks. We present pilot observations from the Heinrich Hertz Submillimeter Telescope and follow-up observations from the Submillimeter Array. All vibrationally excited HCN (4-3) v = 0, v = 1, and v = 2 lines were observed. The existence of the three v = 2 lines at approximately equal intensity imply collisional excitation with a density of greater than (1010 cm-3) and a temperature of >1000 K for the emitting gas. This warm, high-density material should directly trace structures formed in the protostellar envelope and disk environment. Further, the line shapes of the v = 2 emission may suggest a Keplerian disk. This Letter demonstrates the utility of this technique which is of particular interest due to the recent inauguration of the Atacama Large Millimeter Array.

Original languageEnglish (US)
Article numberL34
JournalAstrophysical Journal Letters
Volume765
Issue number2
DOIs
StatePublished - Mar 10 2013

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Keywords

  • ISM: molecules
  • stars: formation
  • stars: individual (AFGL 2591)
  • stars: kinematics and dynamics
  • stars: protostars
  • submillimeter: stars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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