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 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 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.

scholarly journals The Observational Evidence for Accretion

1997 ◽  
Vol 182 ◽  
pp. 391-405 ◽  
Author(s):  
Lee Hartmann
Keyword(s):  
Large Range ◽  
Observational Evidence ◽  
Young Stars ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
T Tauri ◽  
Accretion Rates ◽  
Low Mass ◽  
Stellar Magnetospheres ◽  
Mass Ejection

Outflows from low-mass young stellar objects are thought to draw upon the energy released by accretion onto T Tauri stars. I briefly summarize the evidence for this accretion and outline present estimates of mass accretion rates. Young stars show a very large range of accretion rates, and this has important implications for both mass ejection and for the structure of stellar magnetospheres which may truncate T Tauri disks.

Submillimeter CO Spectroscopy of Low Mass Young Stellar Objects

1995 ◽  
pp. 117-120
Author(s):  
K. F. Schuster ◽  
A. P. G. Russell ◽  
A. I. Harris
Keyword(s):  
Young Stellar Objects ◽  
Stellar Objects ◽  
Low Mass

scholarly journals Physical Properties of Molecular Envelopes in Low-Mass Star-Forming Regions

2000 ◽  
Vol 197 ◽  
pp. 61-70
Author(s):  
Nagayoshi Ohashi
Keyword(s):  
Physical Properties ◽  
Young Stellar Objects ◽  
Mass Star ◽  
Narrow Line ◽  
Stellar Objects ◽  
Velocity Pattern ◽  
Star Forming ◽  
Star Forming Regions ◽  
Low Mass ◽  
Line Widths

We have carried out interferometric observations of pre-protostellar and protostellar envelopes in Taurus. Protostellar envelopes are dense gaseous condensations with young stellar objects or protostars, while pre-protostellar envelopes are those without any known young stellar objects. Five pre-protostellar envelopes have been observed in CCS JN=32–21, showing flattened and clumpy structures of the envelopes. The observed CCS spectra show moderately narrow line widths, ~0.1 to ~0.35 km s–1. One pre-protostellar envelope, L1544, shows a remarkable velocity pattern, which can be explained in terms of infall and rotation. Our C18O J=1–0 observations of 8 protostellar envelopes show that they have also flattened structures like pre-protostellar envelopes but no clumpy structures. Four out the eight envelopes show velocity patterns that can be explained by motions of infall (and rotation). Physical properties of pre-protostellar and protostellar envelopes are discussed in detail.

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 A Systematic Study of X-Ray Flares from Low-Mass Young Stellar Objects in the $\rho$ Ophiuchi Star-Forming Region with Chandra

2003 ◽  
Vol 55 (3) ◽  
pp. 653-681 ◽  
Author(s):  
Kensuke Imanishi ◽  
Hiroshi Nakajima ◽  
Masahiro Tsujimoto ◽  
Katsuji Koyama ◽  
Yohko Tsuboi
Keyword(s):  
Systematic Study ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
X Ray ◽  
Star Forming ◽  
Low Mass ◽  
Rho Ophiuchi

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
Sign in / Sign up

Export Citation Format

Share Document