scholarly journals X-ray emission from T Tauri stars and the role of accretion: inferences from the XMM-Newton extended survey of the Taurus molecular cloud

2007 ◽  
Vol 468 (2) ◽  
pp. 425-442 ◽  
Author(s):  
A. Telleschi ◽  
M. Güdel ◽  
K. R. Briggs ◽  
M. Audard ◽  
F. Palla
Keyword(s):  
Molecular Cloud ◽  
T Tauri Stars ◽  
X Ray ◽  
T Tauri ◽  
Taurus Molecular Cloud

scholarly journals Accretion and outflow-related X-rays in T Tauri stars

2007 ◽  
Vol 3 (S243) ◽  
pp. 155-162 ◽  
Author(s):  
Manuel Güdel ◽  
Kevin Briggs ◽  
Kaspar Arzner ◽  
Marc Audard ◽  
Jérôme Bouvier ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
T Tauri Stars ◽  
Stellar Surface ◽  
X Rays ◽  
X Ray ◽  
T Tauri ◽  
New Type ◽  
Taurus Molecular Cloud

AbstractWe report on accretion- and outflow-related X-rays from T Tauri stars, based on results from the “XMM-Newton Extended Survey of the Taurus Molecular Cloud.” X-rays potentially form in shocks of accretion streams near the stellar surface, although we hypothesize that direct interactions between the streams and magnetic coronae may occur as well. We report on the discovery of a “soft excess” in accreting T Tauri stars supporting these scenarios. We further discuss a new type of X-ray source in jet-driving T Tauri stars. It shows a strongly absorbed coronal component and a very soft, weakly absorbed component probably related to shocks in microjets. The excessive coronal absorption points to dust-depletion in the accretion streams.

scholarly journals Role of local absorption on the X-ray emission from MHD accretion shocks in classical T Tauri stars

2014 ◽  
Vol 64 ◽  
pp. 05004
Author(s):  
Bonito ◽  
Orlando ◽  
Argiroffi ◽  
Miceli ◽  
Reale ◽  
...  
Keyword(s):  
T Tauri Stars ◽  
X Ray ◽  
T Tauri ◽  
Accretion Shocks

scholarly journals X-rays from accretion shocks in classical T Tauri stars: 2D MHD modeling and the role of local absorption

2013 ◽  
Vol 9 (S302) ◽  
pp. 48-49
Author(s):  
C. Argiroffi ◽  
R. Bonito ◽  
S. Orlando ◽  
M. Miceli ◽  
F. Reale ◽  
...  
Keyword(s):  
Magnetic Field ◽  
T Tauri Stars ◽  
X Rays ◽  
X Ray ◽  
T Tauri ◽  
Shock Region ◽  
Post Shock ◽  
The Magnetic Field ◽  
Accretion Shocks

AbstractIn classical T Tauri stars (CTTS) strong shocks are formed where the accretion funnel impacts with the denser stellar chromosphere. Although current models of accretion provide a plausible global picture of this process, some fundamental aspects are still unclear: the observed X-ray luminosity in accretion shocks is order of magnitudes lower than predicted; the observed density and temperature structures of the hot post-shock region are puzzling and still unexplained by models.To address these issues we performed 2D MHD simulations describing an accretion stream impacting onto the chromosphere of a CTTS, exploring different configurations and strengths of the magnetic field. From the model results we then synthesized the X-ray emission emerging from the hot post-shock, taking into account the local absorption due to the pre-shock stream and surrounding atmosphere.We find that the different configurations and strengths of the magnetic field profoundly affect the hot post-shock properties. Moreover the emerging X-ray emission strongly depends also on the viewing angle under which accretion is observed. Some of the explored configuration are able to reproduce the observed features of X-ray spectra of CTTS.

scholarly journals Magnetohydrodynamic Modeling of the Accretion Shocks in Classical T Tauri Stars: The Role of Local Absorption in the X-Ray Emission

2014 ◽  
Vol 795 (2) ◽  
pp. L34 ◽  
Author(s):  
R. Bonito ◽  
S. Orlando ◽  
C. Argiroffi ◽  
M. Miceli ◽  
G. Peres ◽  
...  
Keyword(s):  
T Tauri Stars ◽  
X Ray ◽  
T Tauri ◽  
Accretion Shocks

scholarly journals Aperture synthesis CS and 98 GHz continuum observations of protostellar IRAS sources in Taurus

1991 ◽  
Vol 147 ◽  
pp. 353-356
Author(s):  
N. Ohashi ◽  
R. Kawabe ◽  
M. Hayashi ◽  
M. Ishiguro
Keyword(s):  
Molecular Cloud ◽  
Total Mass ◽  
T Tauri Stars ◽  
Continuum Emission ◽  
Beam Size ◽  
Dust Grains ◽  
Dynamical Mass ◽  
T Tauri ◽  
Cloud Cores ◽  
The Continuum

The CS (J = 2 — 1) line and 98 GHz continuum emission have been observed for 11 protostellar IRAS sources in the Taurus molecular cloud with resolutions of 2.6″−8.8″ (360 AU—1200 AU) using the Nobeyama Millimeter Array (NMA). The CS emission is detected only toward embedded sources, while the continuum emission from dust grains is detected only toward visible T Tauri stars except for one embedded source, L1551-IRS5. This suggests that the dust grains around the embedded sources do not centrally concentrate enough to be detected with our sensitivity (∼4 m Jy r.m.s), while dust grains in disks around the T Tauri stars have enough total mass to be detected with the NMA. The molecular cloud cores around the embedded sources are moderately extended and dense enough to be detected in CS, while gas disks around the T Tauri are not detected because the radius of such gas disks may be smaller than 70 (50 K/Tex) AU. These results imply that the total amount of matter within the NMA beam size must increase when the central objects evolve into T Tauri stars from embedded sources, suggesting that the compact and highly dense disks around T Tauri stars are formed by the dynamical mass accretion during the embedded protostar phase.

T Tauri Stars: The X-Ray Connection

1999 ◽  
pp. 119-120
Author(s):  
V. M. Costa ◽  
M. T. V. T. Lago
Keyword(s):  
T Tauri Stars ◽  
X Ray ◽  
T Tauri

scholarly journals Spectroscopic diagnostics of T Tauri inner winds

2007 ◽  
Vol 3 (S243) ◽  
pp. 171-182 ◽  
Author(s):  
Suzan Edwards
Keyword(s):  
Velocity Component ◽  
High Velocity ◽  
T Tauri Stars ◽  
Interaction Region ◽  
Spectroscopic Diagnostics ◽  
T Tauri ◽  
Spectral Diagnostics ◽  
Launch Site ◽  
Wide Range

AbstractThe role of the star-disk interaction region in launching the high velocity component of accretion-driven outflows is examined. Spectroscopic indicators of high velocity inner winds have been recognized in T Tauri stars for decades, but identifying the wind launch site and the accompanying mass loss rates has remained elusive. A promising new diagnostic is He I λ10830, whose metastable lower level results in a powerful probe of the geometry of the outflowing gas in the interaction region. This, together with other atomic and molecular spectral diagnostics covering a wide range of excitation and ionization states, suggests that more than one launch site of the innermost wind is operational in most accreting stars.

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