2017/06/12 by Tomoya Hirota, Masahiro N. Machida, Yuko Matsushita +6 · 7 citations
Chemistry · Physics and Astronomy · #Angular momentum #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Bipolar outflow #Jet (fluid) #Mechanics #Millimeter #Molecular Spectroscopy and Structure #Outflow #Physics #Protostar #Rotation (mathematics) #Star formation #Stars #Stellar, planetary, and galactic studies #Submillimeter Array #Young stellar object #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1038/s41550-017-0146
published as Nature Astronomy, 1, 146 (2017) · 16 pages, 8 figures. Accepted version of the manuscript before editing by Nature Astronomy. Published version is available on the SharedIt link; http://rdcu.be/AfTC
openalex publication_date 2017/06/12 · arxiv created 2017/12/13 · arxiv updated 2017/12/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
One of the outstanding problems in star-formation theory concerns the transfer of angular momentum such that mass can accrete onto a newly born young stellar object (YSO). From a theoretical standpoint, outflows and jets are predicted to play an essential role in angular momentum transfer and their rotation motions have been reported for both low- and high-mass YSOs. However, little quantitative discussion on outflow launching mechanisms have been presented for high-mass YSOs due to a lack of observational data. Here we present a clear signature of rotation in the bipolar outflow driven by Orion Source I, a high-mass YSO candidate, using the Atacama Large Millimeter/Submillimeter Array (ALMA). A rotational transition of silicon monoxide (Si18O) reveals a velocity gradient perpendicular to the outflow axis which is consistent with that of the circumstellar disk traced by a high-excitation water (H2O) line. The launching radii and outward velocity of the outflow are estimated to be >10 au and 10 km s-1, respectively. These parameters rule out a possibility that the observed outflow is produced by entrainment of a high-velocity jet, and that contribution from stellar-wind or X-wind which have smaller launching radii are significant in the case of Source I. Thus, present results provide a convincing evidence of a rotating outflow directly driven by the magneto-centrifugal disk wind launched by a high-mass YSO candidate.