2006/07/07 by Satoko Takahashi, Masao Saito, Shigehisa Takakuwa +1 · 2 citations
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Angular momentum #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Envelope (radar) #Millimeter #Molecular Spectroscopy and Structure #Outflow #Physics #Protostar #Specific relative angular momentum #Star formation #Stars #Submillimeter Array #Total angular momentum quantum number #astro-ph
paper · pdf · doi:10.1086/507482
published as Astrophys.J.651:933-944,2006 · 19 pages, 9 figures, ApJ accepted paper
arxiv created 2006/07/07 · openalex publication_date 2006/11/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report the results of H 13 CO + (1-0), CO (1-0), and 3.3 mm dust continuum observations toward MMS 7, one of the strongest millimeter-wave sources in OMC-3, with the Nobeyama Millimeter Array (NMA) and the Nobeyama 45 m telescope. With the NMA, we detected centrally condensed 3.3 mm dust continuum emission, which coincides with the mid-infrared (MIR) source and the free-free jet. Our H 13 CO + observations revealed a disklike envelope around MMS 7, whose size and mass are 0.15 × 0.11 pc and 5.1 M ☉ , respectively. The outer portion of the disklike envelope has a fan-shaped structure, which delineates the rim of the observed CO outflow. The position-velocity diagrams in the H 13 CO + (1-0) emission show that the velocity field in the disklike envelope is composed of a dispersing gas motion and a possible rigid-like rotation. The mass-dispersing rate is estimated to be 3.4 × 10 -5 M ☉ yr -1 , which implies that MMS 7 has an ability to disperse ~10 M ☉ during the protostellar evolutional time. The specific angular momentum in the disklike envelope is nearly 2 orders of magnitude larger than that in low-mass cores. The turnover point of the power law of the angular momentum distribution in the disklike envelope (≤0.007 pc), which is likely to be related to the outer radius of the central mass accretion, is similar in size to the 3.3 mm dust condensation. We propose that MMS 7 is in the last stage of the main accretion phase and that a substantial portion of the outer gas has already been dispersed, while mass accretion may still be ongoing at the innermost region, traced by the dusty condensation.