TY - JOUR
T1 - Disk-driven rotating bipolar outflow in Orion Source i
AU - Hirota, Tomoya
AU - Machida, Masahiro N.
AU - Matsushita, Yuko
AU - Motogi, Kazuhito
AU - Matsumoto, Naoko
AU - Kim, Mi Kyoung
AU - Burns, Ross A.
AU - Honma, Mareki
N1 - Funding Information:
is supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT)/Japan Society for the Promotion of Science (JSPS) KAKENHI grant numbers 21224002, 24684011, 25108005 and 15H03646 and the ALMA Japan Research Grant of the NAOJ Chile Observatory, NAOJ-ALMA-0006,-0028 and-0066. M.N.M. is supported by MEXT/JSPS KAKENHI grant numbers 15K05032 and 17K05387. K.M. is supported by MEXT/JSPS KAKENHI grant number 15K17613. M.H. is supported by MEXT/JSPS KAKENHI grant numbers 24540242 and 25120007. Data analyses were in part carried out on the common use data analysis computer system at the Astronomy Data Center, NAOJ.
Publisher Copyright:
© 2017 Macmillan Publishers Limited.
PY - 2017/3/2
Y1 - 2017/3/2
N2 - One of the outstanding problems in star formation theory concerns the transfer of angular momentum so 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 the transfer of angular momentum 1,2,3,4 and their rotations have been reported for both low-5 and high-mass 6,7 YSOs. However, little quantitative discussion on outflow launching mechanisms has 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 (Si 18 O) reveals a velocity gradient perpendicular to the outflow axis, which is consistent with that of the circumstellar disk traced by a high excitation water line. The launching radii and outward velocity of the outflow are estimated to be >10 au and 10 km s â '1, respectively. These parameters rule out the possibility that the observed outflow is produced by the entrainment of a high-velocity jet 8, and that contributions from the stellar wind 9 or X-wind 10, which have smaller launching radii, are significant in the case of Source I. Thus these results provide convincing evidence of a rotating outflow directly driven by the magneto-centrifugal disk wind launched by a high-mass YSO candidate 6,11.
AB - One of the outstanding problems in star formation theory concerns the transfer of angular momentum so 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 the transfer of angular momentum 1,2,3,4 and their rotations have been reported for both low-5 and high-mass 6,7 YSOs. However, little quantitative discussion on outflow launching mechanisms has 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 (Si 18 O) reveals a velocity gradient perpendicular to the outflow axis, which is consistent with that of the circumstellar disk traced by a high excitation water line. The launching radii and outward velocity of the outflow are estimated to be >10 au and 10 km s â '1, respectively. These parameters rule out the possibility that the observed outflow is produced by the entrainment of a high-velocity jet 8, and that contributions from the stellar wind 9 or X-wind 10, which have smaller launching radii, are significant in the case of Source I. Thus these results provide convincing evidence of a rotating outflow directly driven by the magneto-centrifugal disk wind launched by a high-mass YSO candidate 6,11.
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U2 - 10.1038/s41550-017-0146
DO - 10.1038/s41550-017-0146
M3 - Article
AN - SCOPUS:85027160594
VL - 1
JO - Nature Astronomy
JF - Nature Astronomy
SN - 2397-3366
M1 - 0146
ER -