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

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.

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Multi-epoch water maser survey towards low-mass YSOs

Symposium - International Astronomical Union ◽

10.1017/s0074180900222018 ◽

2002 ◽

Vol 206 ◽

pp. 35-38 ◽

Cited By ~ 1

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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The Observational Evidence for Accretion

Symposium - International Astronomical Union ◽

10.1017/s0074180900061805 ◽

1997 ◽

Vol 182 ◽

pp. 391-405 ◽

Cited By ~ 2

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.

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Erratum: “Water Maser Survey toward Low‐Mass Young Stellar Objects in the Northern Sky with the Nobeyama 45 Meter Telescope and the Very Large Array” (ApJS, 144, 71 [2003])

The Astrophysical Journal Supplement Series ◽

10.1086/516825 ◽

2007 ◽

Vol 171 (1) ◽

pp. 349-351 ◽

Cited By ~ 3

Author(s):

Ray S. Furuya ◽

Yoshimi Kitamura ◽

Alwyn Wootten ◽

Mark J. Claussen ◽

Ryohei Kawabe

Keyword(s):

Young Stellar Objects ◽

Large Array ◽

Stellar Objects ◽

Very Large Array ◽

Low Mass ◽

Water Maser

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Compact Molecular Outflows from Young Stellar Objects in L1641

The Role of Dust in the Formation of Stars - ESO Astrophysics Symposia ◽

10.1007/978-3-540-68594-4_3 ◽

1996 ◽

pp. 11-14

Author(s):

J. C. Correia ◽

M. Griffin ◽

P. Saraceno ◽

A. Zavagno

Keyword(s):

Young Stellar Objects ◽

Stellar Objects ◽

Molecular Outflows

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Submillimeter CO Spectroscopy of Low Mass Young Stellar Objects

Circumstellar Matter 1994 ◽

10.1007/978-94-011-0147-9_22 ◽

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

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

Symposium - International Astronomical Union ◽

10.1017/s007418090016468x ◽

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.

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Mass Outflows Associated with Young Stellar Objects

Symposium - International Astronomical Union ◽

10.1017/s0074180900095620 ◽

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.

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