Abstract
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.
| Original language | English (US) |
|---|---|
| Article number | 73 |
| Journal | Astrophysical Journal |
| Volume | 873 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2019 |
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Keywords
- ISM: individual objects (G339.88-1.26)
- ISM: jets and outflows
- ISM: kinematics and dynamics
- ISM: molecules
- stars: formation
- stars: massive
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
An Ordered Envelope-Disk Transition in the Massive Protostellar Source G339.88-1.26. / Zhang, Yichen; Tan, Jonathan C.; Sakai, Nami; Tanaka, Kei E.I.; De Buizer, James M.; Liu, Mengyao; Beltrán, Maria T.; Kratter, Kaitlin; Mardones, Diego; Garay, Guido.
In: Astrophysical Journal, Vol. 873, No. 1, 73, 01.01.2019.Research output: Contribution to journal › Article
}
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
PY - 2019/1/1
Y1 - 2019/1/1
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
UR - http://www.scopus.com/inward/record.url?scp=85063584794&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85063584794&partnerID=8YFLogxK
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 -