Evolution of outflow activity around low mass embedded young stellar objects

2007 ◽  
pp. 270-275 ◽  
Author(s):  
S. Bontemps ◽  
P. André ◽  
S. Terebey ◽  
S. Cabrit
Keyword(s):  
Young Stellar Objects ◽  
Stellar Objects ◽  
Low Mass

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 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 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 Infalling Streamer-Disk-Outflow System in a Nearby High-mass Star Formation Region

2021 ◽  
Author(s):  
Xi Chen ◽  
Zhiyuan Ren ◽  
Da-Lei Li ◽  
Tie Liu ◽  
Ke Wang ◽  
...  
Keyword(s):  
Direct Detection ◽  
Theoretical Models ◽  
Young Stellar Objects ◽  
High Mass ◽  
Similar Process ◽  
Mass Star ◽  
Solar Mass ◽  
Low Mass Stars ◽  
Stellar Objects ◽  
Low Mass

Abstract Theoretical models and numerical simulations suggest that high mass star (with mass > 8 solar mass) can be formed either via monolithic collapse of a massive core or competitive accretion, but the dominant mechanism is currently unclear. Although recent high resolution observations with the Atacama Large Millimeter/submillimeter Array (ALMA) have detected physical and kinematic features, such as disks, outflows and filamentary structures surrounding the high mass young stellar objects (HMYSO), direct detection of the infalling gas towards the HMYSO is still the key to distinguish the different scenarios. Chemically fresh gas inflows have been detected towards low-mass stars being formed, which are consistent with the accretion-disk-outflow process. In this work we report the detection of a chemically fresh inflow which is feeding HMYSO growth in the nearby high mass star-forming region G352.63-1.07. High quality images of the dust and molecular lines from both ALMA and the Submillimeter Array (SMA) have consistently revealed a gravitationally-controlled gas inflow towards a rotating structure (disk or torus) around the HMYSO. The HMYSO is also observed to have an outflow, but it can be clearly separated from the inflow. These kinematic features provide observational evidence to support the conjecture that high-mass stars can be formed in a similar process to that observed in the low-mass counterparts. The chemically fresh infalling streamers could also be related with the disk configuration, fragmentation and accretion bursts that occur in both simulations and observations.

scholarly journals APEX-CHAMP+high-JCO observations of low-mass young stellar objects

2015 ◽  
Vol 576 ◽  
pp. A109 ◽  
Author(s):  
U. A. Yıldız ◽  
L. E. Kristensen ◽  
E. F. van Dishoeck ◽  
M. R. Hogerheijde ◽  
A. Karska ◽  
...  
Keyword(s):  
Young Stellar Objects ◽  
Stellar Objects ◽  
Low Mass

scholarly journals A wide survey for circumstellar disks in the Lupus complex

2020 ◽  
Vol 642 ◽  
pp. A86
Author(s):  
P. S. Teixeira ◽  
A. Scholz ◽  
J. Alves
Keyword(s):  
Three Dimensional ◽  
Circumstellar Disks ◽  
Young Stellar Objects ◽  
Dimensional Structure ◽  
Spectral Energy ◽  
Mass Star ◽  
Nearby Star ◽  
Stellar Objects ◽  
Star Forming ◽  
Low Mass

Previous star formation studies have, out of necessity, often defined a population of young stars confined to the proximity of a molecular cloud. Gaia allows us to examine a wider, three-dimensional structure of nearby star forming regions, leading to a new understanding of their history. We present a wide-area survey covering 494 deg2 of the Lupus complex, a prototypical low-mass star forming region. Our survey includes all known molecular clouds in this region as well as parts of the Upper Scorpius and Upper Centaurus Lupus (UCL) groups of the Sco-Cen complex. We combine Gaia DR2 proper motions and parallaxes as well as ALLWISE mid-infrared photometry to select young stellar objects (YSOs) with disks. The YSO ages are inferred from Gaia color-magnitude diagrams, and their evolutionary stages from the slope of the spectral energy distributions. We find 98 new disk-bearing sources. Our new sample includes objects with ages ranging from 1 to 15 Myr and masses ranging from 0.05 to 0.5 M⊙, and consists of 56 sources with thick disks and 42 sources with anemic disks. While the youngest members are concentrated in the clouds and at distances of 160 pc, there is a distributed population of slightly older stars that overlap in proper motion, spatial distribution, distance, and age with the Lupus and UCL groups. The spatial and kinematic properties of the new disk-bearing YSOs indicate that Lupus and UCL are not distinct groups. Our new sample comprises some of the nearest disks to Earth at these ages, and thus provides an important target for follow-up studies of disks and accretion in very low mass stars, for example with ALMA and ESO-VLT X-shooter.

Water Maser Survey toward Low‐Mass Young Stellar Objects in the Northern Sky with the Nobeyama 45 Meter Telescope and the Very Large Array

2003 ◽  
Vol 144 (1) ◽  
pp. 71-134 ◽  
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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