ALMA discovery of a dual dense probably rotating outflow from a massive young stellar object G18.88MME
arXiv:2106.09626 · doi:10.1093/mnrasl/slab070
Abstract
We report the discovery of a very dense jet-like fast molecular outflow surrounded by a wide-angle wind in a massive young stellar object (MYSO) G18.88MME (stellar mass 8 M) powering an Extended Green Object G18.890.47. Four cores MM1-4 are identified in the Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum map (resolution 0.8) toward G18.88MME, and are seen at the center of the emission structure (extent 0.3 pc 0.2 pc) detected in the ALMA map. G18.88MME is embedded in the core MM1 (mass 13-18 M), where no radio continuum emission is detected. The molecular outflow centered at MM1 is investigated in the SiO(5-4), HCN(24-23) and CO(2-1) lines. The detection of HCN in the outflow is rare in MYSOs and indicates its very high density. The position-velocity diagrams display a fast narrow outflow (extent 28000 AU) and a slower wide-angle more extended outflow toward MM1, and both of these components show a transverse velocity gradient indicative of a possible rotation. All these observed features together make G18.88MME as a unique object for studying the unification of the jet-driven and wind-driven scenarios of molecular outflows in MYSOs.
arXiv comment5 pages, 6 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society
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