Frequency distribution of x-ray flares for low-mass young stellar objects in the Orion nebula

Astrophysics ◽  
2012 ◽  
Vol 55 (4) ◽  
pp. 505-514 ◽  
Author(s):  
A. A. Akopian
Keyword(s):  
Frequency Distribution ◽  
Young Stellar Objects ◽  
Orion Nebula ◽  
Stellar Objects ◽  
X Ray ◽  
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 3D shape of Orion A with Gaia DR2 An informed view on Star Formation Rates and Efficiencies

2018 ◽  
Vol 14 (S345) ◽  
pp. 27-33
Author(s):  
Josefa E. Großschedl ◽  
João Alves ◽  
Stefan Meingast ◽  
Birgit Hasenberger
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Young Stellar Objects ◽  
Mass Star ◽  
Orion Nebula ◽  
Stellar Objects ◽  
Star Forming ◽  
The North ◽  
Low Mass ◽  
The Rich

AbstractThe giant molecular cloud Orion A is the closest massive star-forming region to earth (d ∼ 400 pc). It contains the rich Orion Nebula Cluster (ONC) in the North, and low-mass star-forming regions (L1641, L1647) to the South. To get a better understanding of the differences in star formation activity, we perform an analysis of the gas mass distribution and star formation rate across the cloud. We find that the gas is roughly uniformly distributed, while, oddly, the ONC region produced about a factor of ten more stars compared to the rest of the cloud. For a better interpretation of this phenomenon, we use Gaia DR2 parallaxes, to analyse distances of young stellar objects, using them as proxy for cloud distances. We find that the ONC region indeed lies at about 400 pc while the low-mass star-forming parts are inclined about 70∘ from the plane of the sky reaching until ∼470 pc. With this we estimate that Orion A is an about 90 pc long filamentary cloud (about twice as long as previously assumed), with its “Head” (the ONC region) being “bent” and oriented towards the galactic mid-plane. This striking new view allows us to perform a more robust analysis of this important star-forming region in the future.

scholarly journals X‐Ray Emission from Young Stellar Objects in the ε Chamaeleontis Group: The Herbig Ae Star HD 104237 and Associated Low‐Mass Stars

2008 ◽  
Vol 687 (1) ◽  
pp. 579-597 ◽  
Author(s):  
Paola Testa ◽  
David P. Huenemoerder ◽  
Norbert S. Schulz ◽  
Kazunori Ishibashi
Keyword(s):  
Young Stellar Objects ◽  
Low Mass Stars ◽  
Stellar Objects ◽  
X Ray ◽  
Low Mass

scholarly journals Extreme Radio Flares and Associated X-Ray Variability from Young Stellar Objects in the Orion Nebula Cluster

2017 ◽  
Vol 844 (2) ◽  
pp. 109 ◽  
Author(s):  
Jan Forbrich ◽  
Mark J. Reid ◽  
Karl M. Menten ◽  
Victor M. Rivilla ◽  
Scott J. Wolk ◽  
...  
Keyword(s):  
Young Stellar Objects ◽  
Orion Nebula ◽  
Stellar Objects ◽  
X Ray

The Formation of Astrophysical Jets

1997 ◽  
Vol 163 ◽  
pp. 845-866 ◽  
Author(s):  
Mario Livio
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Young Stellar Objects ◽  
Astrophysical Jets ◽  
Stellar Objects ◽  
X Ray ◽  
Astrophysical Objects ◽  
Low Mass ◽  
Wind Source ◽  
X Ray Binaries

AbstractIt is assumed that the acceleration and collimation mechanisms of jets are the same in all the classes of astrophysical objects which are observed to produce jets. These classes now include: active galactic nuclei, young stellar objects, massive x-ray binaries, low mass x-ray binaries, black hole x-ray transients, symbiotic systems, planetary nebulae, and supersoft x-ray sources.On the basis of this assumption, an attempt is made, to identify the necessary ingredients for the acceleration and collimation mechanism. It is argued that: (i) jets are produced at the center of accretion disks which are threaded by a vertical magnetic field, (ii) the production of powerful jets requires, in addition, an energy/wind source associated with the central object. Tentative explanations for the presence of jets in some classes of objects and absence in others are given. Some critical observation that can test the ideas presented in this paper are suggested.

scholarly journals Accretion in low-mass members of the Orion Nebula Cluster with young transition disks

2020 ◽  
Vol 636 ◽  
pp. A86 ◽  
Author(s):  
R. M. G. de Albuquerque ◽  
J. F. Gameiro ◽  
S. H. P. Alencar ◽  
J. J. G. Lima ◽  
C. Sauty ◽  
...  
Keyword(s):  
Circumstellar Disks ◽  
Mass Range ◽  
Solar Neighborhood ◽  
Young Stellar Objects ◽  
Orion Nebula ◽  
Stellar Objects ◽  
Accretion Rates ◽  
Show Evidence ◽  
Low Mass ◽  
Transition Disks

Context. Although the Orion Nebula Cluster is one of the most studied clusters in the solar neighborhood, the evolution of the very low-mass members (M* < 0.25 M⊙) has not been fully addressed due to their faintness. Aims. Our goal is to verify if some young and very low-mass objects in the Orion Nebula Cluster show evidence of ongoing accretion using broadband VLT/X-shooter spectra. Methods. For each target, we determined the corresponding stellar parameters, veiling, observed Balmer jump, and accretion rates. Additionally, we searched for the existence of circumstellar disks through available on-line photometry. Results. We detected accretion activity in three young stellar objects in the Orion Nebula Cluster, two of them being in the very low-mass range. We also detected the presence of young transition disks with ages between 1 and 3.5 Myr.

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.

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