scholarly journals Molecular outflows towards O-type young stellar objects

2009 ◽  
Vol 499 (3) ◽  
pp. 811-825 ◽  
Author(s):  
A. López-Sepulcre ◽  
C. Codella ◽  
R. Cesaroni ◽  
N. Marcelino ◽  
C. M. Walmsley
Keyword(s):  
Young Stellar Objects ◽  
Stellar Objects ◽  
Molecular Outflows

scholarly journals Mass Outflows Associated with Young Stellar Objects

1987 ◽  
Vol 115 ◽  
pp. 255-273
Author(s):  
Stephen E. Strom ◽  
Karen M. Strom
Keyword(s):  
Magnetic Field ◽  
Molecular Clouds ◽  
Circumstellar Disks ◽  
Young Stellar Objects ◽  
Molecular Flow ◽  
Birth Process ◽  
Stellar Objects ◽  
Molecular Outflows ◽  
Bolometric Luminosity ◽  
Field Geometry

The fundamental properties of optical and molecular outflows associated with young stellar objects are reviewed. Particular emphasis is placed on a discussion of new results concerning outflow energetics, collimating structures and the relationship between outflow properties and the magnetic field geometry characterizing their host molecular clouds. IRAS observations of YSO mass outflows reveal extended far-IR emission associated with high velocity molecular gas; in the case of L1551 IRS5, the luminosity of the extended emission is ∼10 times the mechanical luminosity inferred from observation of the molecular flow (and thus ≳0.1 the bolometric luminosity of the YSO driving the outflow). Circumstellar disks of size ∼100 au appear to be a common, if not certain outcome of the stellar birth process for stars of ∼1M⊙. In a few cases, it has been possible to resolve disk-like structures associated with YSO outflow sources. In such cases, the disk axes appear to lie along the direction of molecular outflows or stellar jets. The mass outflows (and by inference, the axes of circumstellar disks) show a remarkable tendency to align along the direction of the magnetic fields which thread their host molecular clouds. This suggests that the cloud magnetic field must play an important role in determining the flattening (and perhaps the rotation) of protostellar structures.

scholarly journals Envelope Structure on 700 AU Scales and the Molecular Outflows of Low‐Mass Young Stellar Objects

1998 ◽  
Vol 502 (1) ◽  
pp. 315-336 ◽  
Author(s):  
Michiel R. Hogerheijde ◽  
Ewine F. van Dishoeck ◽  
Geoffrey A. Blake ◽  
Huib Jan van Langevelde
Keyword(s):  
Young Stellar Objects ◽  
Stellar Objects ◽  
Molecular Outflows ◽  
Low Mass

scholarly journals On the line profiles of shell-shaped bipolar outflows

1987 ◽  
Vol 122 ◽  
pp. 87-88
Author(s):  
G. Silvestro ◽  
M. Robberto
Keyword(s):  
Shell Structure ◽  
High Velocity ◽  
Young Stellar Objects ◽  
Structure Characteristic ◽  
Line Profiles ◽  
Bipolar Outflows ◽  
Stellar Objects ◽  
Interstellar Clouds ◽  
Molecular Outflows

High velocity molecular outflows with bipolar morphology are detected in association with young stellar objects within dense interstellar clouds. Recent observations suggest that the flow could be “confined to a relatively thin, swept-up shell surrounding an evacuated wind cavity” (1). A shell structure characteristic of the wind-cloud interaction had been predicted in earlier theoretical works (see for instance (2)). More recently, models with different (not shell-shaped) geometries were presented, e.g. (3).

High-velocity molecular outflows hear massive young stellar objects

1999 ◽  
Vol 42 (7) ◽  
pp. 732-738 ◽  
Author(s):  
Yuefang Wu ◽  
Chuanyi Yang ◽  
Yuexing Li ◽  
Chengming Lei ◽  
Jinjiang Sun ◽  
...  
Keyword(s):  
High Velocity ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
Molecular Outflows

scholarly journals Molecular Outflows in B335 and B1

1994 ◽  
Vol 140 ◽  
pp. 224-225
Author(s):  
N. Hirano ◽  
O. Kameya ◽  
T. Kasuga ◽  
H. Mikami ◽  
S. Saito ◽  
...  
Keyword(s):  
Aperture Synthesis ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
Molecular Outflows ◽  
Low Mass

We present the aperture synthesis observations of the CO molecular outflows associated with the low-mass young stellar objects embedded in B335 and Bl. We used the Nobeyama Millimeter Array and obtained the angular resolutions of 8.1” × 5.0” for B335 and 6.5” × 4.4” for B1.

scholarly journals Shock Chemistry in Bipolar Molecular Outflows

1997 ◽  
Vol 182 ◽  
pp. 153-162 ◽  
Author(s):  
R. Bachiller ◽  
M. Pérez Gutiérrez
Keyword(s):  
Chemical Composition ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
Molecular Outflows ◽  
Molecular Outflow ◽  
Interstellar Ice ◽  
Chemical Studies ◽  
Molecular Lines

Chemical studies have a great potential to study the structure and evolution of the bipolar molecular outflows driven by young stellar objects. In this paper, we discuss some very recent mm-wave studies of L 1157, a bipolar molecular outflow driven by a Class 0 protostar. These observations are very useful to illustrate the chemical alterations produced by a violent highly-collimated outflow. Different molecular lines are observed to trace different components of the gas. Some molecules are abundant in the quiescent medium but are not observed in the shock (e.g. C3H2, N2H+, H13CO+, DCO+), whereas some otherwise rare molecules are very enhanced at the shocked region (e.g. SiO, CH3OH, H2CO, HCN, CN, SO, SO2). In addition, we have observed strong gradients in the chemical composition across the outflow blue lobe. We briefly discuss the chemistry of the most important molecules, devoting special attention to the species which are thought to be abundant in interstellar ice mantles.

scholarly journals Molecular Outflows around High-Mass Young Stellar Objects

2006 ◽  
Vol 132 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Y. Xu ◽  
Z.-Q. Shen ◽  
J. Yang ◽  
X. W. Zheng ◽  
A. Miyazaki ◽  
...  
Keyword(s):  
Young Stellar Objects ◽  
High Mass ◽  
Stellar Objects ◽  
Molecular Outflows

scholarly journals Multi-epoch water maser survey towards low-mass YSOs

2002 ◽  
Vol 206 ◽  
pp. 35-38 ◽  
Author(s):  
Ray S. Furuya ◽  
Yoshimi Kitamura ◽  
Alwyn Wootten ◽  
Mark J. Claussen ◽  
Ryohei Kawabe
Keyword(s):  
Large Scale ◽  
Class I ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
Detection Rates ◽  
Molecular Outflows ◽  
Low Mass ◽  
Water Maser

We present the results from a series of multi-epoch 22 GHz H2O maser surveys with the Nobeyama 45 m telescope and the VLA towards low-mass young stellar objects, including all the class 0 sources in the northern sky. Our Nobeyama 45 m survey is the deepest survey - down to an isotopic H2O luminosity of ∼ 10−13L⊙ - performed so far. From this survey, we obtained the following results. (1) Class 0 sources show high H2O maser activity: our derived detection rates are ∼ 38% for class 0, but only ∼ 4% for class I sources. (2) Activity of the H2O masers is more likely related to 100 AU scale ionized jets than to large scale molecular outflows.

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