2005/09/09 by Kevin R. Covey, Thomas P. Greene, Greg W. Doppmann +1 · 4 citations
Chemistry · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #astro-ph
paper · pdf · doi:10.1086/498064
published as Astron.J.131:512-519,2006 · 9 pages in emulate ApJ format, accepted for publication in AJ
arxiv created 2005/09/09 · openalex publication_date 2006/01/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We analyze radial velocities for a sample of 31 Class I and flat-spectrum protostars in Taurus-Auriga, ρ Ophiuchi, and Serpens for evidence of the global dynamical state of extremely young stellar populations buried within parental molecular clouds. Comparing the radial velocity of each protostar to that of the local CO gas, we are able to constrain the one-dimensional radial velocity dispersion of Class I and flat-spectrum objects to ∼2.5 km s -1 or below. This upper limit to the protostellar velocity dispersion is consistent with the velocity dispersions of surrounding CO gas, which we measure to be ∼1.4 km s -1 , suggesting that the motions of protostars and local CO gas are dynamically linked and are dominated by the gravitational potential of the molecular cloud. However, the upper limit on the protostellar velocity dispersion could still allow for slightly inflated motions of protostars relative to the local molecular gas. Four of the protostars analyzed appear to have velocities more than 3 σ (7.5 km s -1 ) away from the central local CO gas velocity while showing spectroscopic indicators of youth and accretion such as H 2 emission, H I Brγ emission, or K -band continuum veiling. These radial velocity outliers may represent protostellar spectroscopic binaries or ejected cluster members.