2018/09/19 by Yiping Ao, Y. Ao, J. Yang +9 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Kinetic energy #Line (geometry) #Luminosity #Protostar #Stellar, planetary, and galactic studies #Turbulence #Virial theorem #Young stellar object #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/aae259
published in The Astronomical Journal 156(5), 210 (Institute of Physics) · 20 pages, 4 figures, accepted for publication in AJ
arxiv created 2018/09/19 · openalex created_date 2018/09/27 · openalex publication_date 2018/10/18 · arxiv updated 2018/11/14 · openalex updated_date 2026/08/06
Abstract We present the results of CS J = 2 → 1 mapping observations toward 39 massive star-forming regions selected from the previous CO line survey of cold IRAS sources with high-velocity CO flows along the Galactic plane. All sources are detected in CS J = 2 → 1, showing the existence of CS clumps around the IRAS sources. However, one-third of the sources are not deeply embedded in the dense clumps by comparison of the central powering IRAS sources and the morphologies of CS clumps. Physical parameters of the dense molecular clumps are presented. We have identified 12 high-mass protostellar object (HMPO) candidates by checking the association between the dense cores and the IRAS sources, the detection of water maser, and the radio properties toward the IRAS sources. We find that the HMPO sources are characterized by low FIR luminosity to virial mass ratios since they are in very early evolutionary stages when the massive protostars have not reached their full luminosities, which are typical for zero-age main-sequence stars. Large turbulent motion in the HMPO sources may be largely due to the large kinetic energy ejected by the central protostars formed in the dense clumps. However, alternative means or undetected outflows may also be responsible for the turbulence in the clumps.