TY - JOUR
T1 - An Ordered Envelope-Disk Transition in the Massive Protostellar Source G339.88-1.26
AU - Zhang, Yichen
AU - Tan, Jonathan C.
AU - Sakai, Nami
AU - Tanaka, Kei E.I.
AU - De Buizer, James M.
AU - Liu, Mengyao
AU - Beltrán, Maria T.
AU - Kratter, Kaitlin
AU - Mardones, Diego
AU - Garay, Guido
N1 - Funding Information:
This paper makes use of the following ALMA data: ADS/ JAO.ALMA#2015.1.01454.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/ NRAO, and NAOJ. Y.Z. acknowledges support from RIKEN Special Postdoctoral Researcher Program. J.C.T. acknowledges support from NSF grant AST1411527 and ERC project 788829 —MSTAR. N.S. acknowledges support from JSPS KAKENHI grant 18H05222. K.E.I.T. acknowledges support from NAOJ ALMA Scientific Research grant No. 2017-05A. D.M. and G.G. acknowledge support from CONICYT project AFB-170002.
PY - 2019
Y1 - 2019
N2 - We report molecular line observations of the massive protostellar source G339.88-1.26 with the Atacama Large Millimeter/Submillimeter Array. The observations reveal a highly collimated SiO jet extending from the 1.3 mm continuum source, which connects to a slightly wider but still highly collimated CO outflow. Rotational features perpendicular to the outflow axis are detected in various molecular emissions, including SiO, SO 2 , H 2 S, CH 3 OH, and H 2 CO emissions. Based on their spatial distributions and kinematics, we find that they trace different parts of the envelope-disk system. The SiO emission traces the disk and inner envelope in addition to the jet. The CH 3 OH and H 2 CO emissions mostly trace the infalling-rotating envelope and are enhanced around the transition region between envelope and disk, i.e., the centrifugal barrier. The SO 2 and H 2 S emissions are enhanced around the centrifugal barrier and also trace the outer part of the disk. Envelope kinematics are consistent with rotating-infalling motion, while those of the disk are consistent with Keplerian rotation. The radius and velocity of the centrifugal barrier are estimated to be about 530 au and 6 , respectively, leading to a central mass of about 11 M o , consistent with estimates based on spectral energy distribution fitting. These results indicate that an ordered transition from an infalling-rotating envelope to a Keplerian disk through a centrifugal barrier, accompanied by changes of types of molecular line emissions, is a valid description of this massive protostellar source. This implies that at least some massive stars form in a similar way to low-mass stars via core accretion.
AB - We report molecular line observations of the massive protostellar source G339.88-1.26 with the Atacama Large Millimeter/Submillimeter Array. The observations reveal a highly collimated SiO jet extending from the 1.3 mm continuum source, which connects to a slightly wider but still highly collimated CO outflow. Rotational features perpendicular to the outflow axis are detected in various molecular emissions, including SiO, SO 2 , H 2 S, CH 3 OH, and H 2 CO emissions. Based on their spatial distributions and kinematics, we find that they trace different parts of the envelope-disk system. The SiO emission traces the disk and inner envelope in addition to the jet. The CH 3 OH and H 2 CO emissions mostly trace the infalling-rotating envelope and are enhanced around the transition region between envelope and disk, i.e., the centrifugal barrier. The SO 2 and H 2 S emissions are enhanced around the centrifugal barrier and also trace the outer part of the disk. Envelope kinematics are consistent with rotating-infalling motion, while those of the disk are consistent with Keplerian rotation. The radius and velocity of the centrifugal barrier are estimated to be about 530 au and 6 , respectively, leading to a central mass of about 11 M o , consistent with estimates based on spectral energy distribution fitting. These results indicate that an ordered transition from an infalling-rotating envelope to a Keplerian disk through a centrifugal barrier, accompanied by changes of types of molecular line emissions, is a valid description of this massive protostellar source. This implies that at least some massive stars form in a similar way to low-mass stars via core accretion.
KW - ISM: individual objects (G339.88-1.26)
KW - ISM: jets and outflows
KW - ISM: kinematics and dynamics
KW - ISM: molecules
KW - stars: formation
KW - stars: massive
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U2 - 10.3847/1538-4357/ab0553
DO - 10.3847/1538-4357/ab0553
M3 - Article
AN - SCOPUS:85063584794
VL - 873
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 73
ER -