Analysis of HST ultraviolet spectra for T Tauri stars: Estimating the interstellar extinction and the contribution from an accretion shock to the emission-continuum formation

2002 ◽  
Vol 28 (12) ◽  
pp. 835-842 ◽  
Author(s):  
A. S. Kravtsova ◽  
S. A. Lamzin
Keyword(s):  
Interstellar Extinction ◽  
T Tauri Stars ◽  
Ultraviolet Spectra ◽  
T Tauri ◽  
Accretion Shock ◽  
Continuum Formation

scholarly journals Formation of Fe X-Fe XIV coronal lines in the accretion shock of T Tauri stars

2001 ◽  
Vol 369 (3) ◽  
pp. 965-970 ◽  
Author(s):  
S. A. Lamzin ◽  
H. C. Stempels ◽  
N. E. Piskunov
Keyword(s):  
T Tauri Stars ◽  
T Tauri ◽  
Accretion Shock

Analysis of HST and IUE ultraviolet spectra for T Tauri stars: DF Tau

2001 ◽  
Vol 27 (5) ◽  
pp. 313-323 ◽  
Author(s):  
S. A. Lamzin ◽  
A. A. Vittone ◽  
L. Errico
Keyword(s):  
T Tauri Stars ◽  
Ultraviolet Spectra ◽  
T Tauri

scholarly journals The circumstellar environment of chromospherically active T Tauri stars

1987 ◽  
Vol 122 ◽  
pp. 103-104
Author(s):  
U. Finkenzeller ◽  
G. Basri
Keyword(s):  
Interstellar Extinction ◽  
T Tauri Stars ◽  
Activity Level ◽  
Young Stellar Objects ◽  
Balmer Line ◽  
Stellar Envelope ◽  
Stellar Objects ◽  
T Tauri ◽  
Type 3 ◽  
Circumstellar Environment

We discuss new spectroscopic material on 7 T Tauri stars of low to intermediate activity level which have envelopes of low optical thickness and small circumstellar/interstellar extinction. We show that difference plots between the target star and appropriate standards are a powerful tool to probe the stellar envelope structure. In our sample we find 1 object with a P Cyg type, 3 with inverse P Cyg type, and 3 with symmetrical Balmer line profiles. We conclude that the physical processes in these T Tauri stars do not differ qualitatively from the ones found in extremely active ones. In particular, the inverse P Cyg type profiles are not restricted to stars with very opaque envelopes and are possibly a much more common attribute of young stellar objects.

scholarly journals X-ray emission from dense plasma in classical T Tauri stars: hydrodynamic modeling of the accretion shock

2008 ◽  
Vol 491 (2) ◽  
pp. L17-L20 ◽  
Author(s):  
G. G. Sacco ◽  
C. Argiroffi ◽  
S. Orlando ◽  
A. Maggio ◽  
G. Peres ◽  
...  
Keyword(s):  
Dense Plasma ◽  
Hydrodynamic Modeling ◽  
T Tauri Stars ◽  
X Ray ◽  
T Tauri ◽  
Accretion Shock

scholarly journals The Structure and Emission of the Accretion Shock in T Tauri Stars

1998 ◽  
Vol 509 (2) ◽  
pp. 802-818 ◽  
Author(s):  
Nuria Calvet ◽  
Erik Gullbring
Keyword(s):  
T Tauri Stars ◽  
T Tauri ◽  
Accretion Shock

Analysis of HST ultraviolet spectra for T Tauri stars: DR Tau

2002 ◽  
Vol 28 (10) ◽  
pp. 676-690 ◽  
Author(s):  
A. S. Kravtsova ◽  
S. A. Lamzin
Keyword(s):  
T Tauri Stars ◽  
Ultraviolet Spectra ◽  
T Tauri

scholarly journals The Structure and Emission of the Accretion Shock in T Tauri Stars. II. The Ultraviolet‐Continuum Emission

2000 ◽  
Vol 544 (2) ◽  
pp. 927-932 ◽  
Author(s):  
Erik Gullbring ◽  
Nuria Calvet ◽  
James Muzerolle ◽  
Lee Hartmann
Keyword(s):  
T Tauri Stars ◽  
Continuum Emission ◽  
Ultraviolet Continuum ◽  
T Tauri ◽  
Accretion Shock

scholarly journals The magnetic obliquity of accreting T Tauri stars

2020 ◽  
Vol 497 (2) ◽  
pp. 2142-2162
Author(s):  
Pauline McGinnis ◽  
Jérôme Bouvier ◽  
Florian Gallet
Keyword(s):  
Radial Velocity ◽  
Rotational Velocity ◽  
T Tauri Stars ◽  
Rotational Axis ◽  
Stellar Rotation ◽  
Magnetic Pole ◽  
T Tauri ◽  
Significant Difference ◽  
Tentative Evidence ◽  
Accretion Shock

ABSTRACT Classical T Tauri stars (CTTSs) accrete material from their discs through their magnetospheres. The geometry of the accretion flow strongly depends on the magnetic obliquity, i.e. the angle between the rotational and magnetic axes. We aim at deriving the distribution of magnetic obliquities in a sample of 10 CTTSs. For this, we monitored the radial velocity variations of the He i λ5876 Å line in these stars’ spectra along their rotational cycle. He i is produced in the accretion shock, close to the magnetic pole. When the magnetic and rotational axes are not aligned, the radial velocity of this line is modulated by stellar rotation. The amplitude of modulation is related to the star’s projected rotational velocity, vsin i, and the latitude of the hotspot. By deriving vsin i and He i λ5876 radial velocity curves from our spectra, we thus obtain an estimate of the magnetic obliquities. We find an average obliquity in our sample of 11.4° with an rms dispersion of 5.4°. The magnetic axis thus seems nearly, but not exactly aligned with the rotational axis in these accreting T Tauri stars, somewhat in disagreement with studies of spectropolarimetry, which have found a significant misalignment (≳20°) for several CTTSs. This could simply be an effect of low number statistics, or it may be due to a selection bias of our sample. We discuss possible biases that our sample may be subject to. We also find tentative evidence that the magnetic obliquity may vary according to the stellar interior and that there may be a significant difference between fully convective and partly radiative stars.

Analysis of HST ultraviolet spectra for T Tauri stars: RU Lup

2000 ◽  
Vol 26 (4) ◽  
pp. 225-232 ◽  
Author(s):  
S. A. Lamzin
Keyword(s):  
T Tauri Stars ◽  
Ultraviolet Spectra ◽  
T Tauri
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