Evidence of Stellar-driven Outflows from the Classical T Tauri Star RY Tau

Castro, Ana Inés Gómez de; Verdugo, E.

doi:10.1086/510849

Cited by 35 publications

(32 citation statements)

References 12 publications

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“…The density profiles of our two solutions are consistent with the densities given by Gómez de Castro & Verdugo (2007). They measure an electronic density of 10 12 cm −3 in the SiIII UV line between 0.006 and 0.3 AU, and 10 10 cm −3 in the CIII] UV semiforbidden line between 0.05 and 1 AU.…”

Section: A Possible Application To the Ry Tau Jetsupporting

confidence: 88%

“…As we have shown in Aibéo et al (2007), the effective temperature can be easily ten times higher than the kinetic one with a relative amplitude of the Alfvén waves δB/B less than unity. Note that Gómez de Castro & Verdugo (2007) inferred from UV lines high electronic temperatures associated with a wind close to 10 5 K consistent with this scenario and an effective temperature of one million degrees.…”

Section: A Model For Low Mass Accreting T Tauri Jetssupporting

confidence: 71%

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Nonradial and nonpolytropic astrophysical outflows

Sauty

Méliani

Lima

et al. 2011

A&A

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Context. A large sample of T Tauri stars exhibits optical jets, approximately half of which rotate slowly, only at ten per cent of their breakup velocity. The disk-locking mechanism has been shown to be inefficient to explain this observational fact. Aims. We show that low mass accreting T Tauri stars may have a strong stellar jet component that can effectively brake the star to the observed rotation speed. Methods. By means of a nonlinear separation of the variables in the full set of the MHD equations we construct semi-analytical solutions describing the dynamics and topology of the stellar component of the jet that emerges from the corona of the star. Results. We analyze two typical solutions with the same mass loss rate but different magnetic lever arms and jet radii. The first solution with a long lever arm and a wide jet radius effectively brakes the star and can be applied to the visible jets of T Tauri stars such as RY Tau. The second solution with a shorter lever arm and a very narrow jet radius may explain why similar stars, either weak line T Tauri stars (WTTS) or classical T Tauri stars (CTTS) do not all have visible jets. For instance, RY Tau itself seems to have different phases that probably depend on the activity of the star. Conclusions. First, stellar jets seem to be able to brake pre-main sequence stars with a low mass accreting rate. Second, jets may be visible only part time owing to changes in their boundary conditions. We also suggest a possible scenario for explaining the dichotomy between CTTS and WTTS, which rotate faster and do not have visible jets.

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Section: A Possible Application To the Ry Tau Jetsupporting

confidence: 88%

Section: A Model For Low Mass Accreting T Tauri Jetssupporting

confidence: 71%

Nonradial and nonpolytropic astrophysical outflows

Sauty

Méliani

Lima

et al. 2011

A&A

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“…Gómez de Castro & Verdugo (2007) analyze the spectrum of RY Tau, and argue that the species with the smallest critical densities are more blueshifted than those with large critical densities, as one would expect from a wind. They do not address how can such wind be heated to the large measured temperatures (60,000 K, based on their C iv/Si iii] line ratios).…”

Section: Predictions Of Modelsmentioning

confidence: 99%

“…Is the emission from the accretion shock region enough to explain those observations, or are other regions of the system contributing to the emission? An understanding of the radiation coming from the accretion shock and its interaction with the rest of the T Tauri system is crucial to map the disk photoevaporation (Alexander et al 2004), model the heating of jets in their launching regions (Gómez de Castro & Verdugo 2007), and interpret broad-band X-ray observations of young stars (Preibisch et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Observations of accretion shocks

Ardila

2007

Proc. IAU

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Abstract. I review our current understanding of accretion shocks in classical T Tauri stars (CTTs), from a UV and X-ray perspective. The region of the accretion shock is a good candidate as a source of UV transition region lines from Li/Na-like ions, which are stronger in CTTs than in naked atmospheres. Disk gas captured by the stellar magnetic field produces a strong radiative shock upon falling on the stellar surface. Radiation from the shock creates a radiative precursor and heats the stellar surface resulting in a hot spot. Stellar and shock models indicate that unless the post-shock column is very large, it will be buried on the stellar photosphere. Models of the continuum emission produced by this configuration can roughly reproduce the observed excess spectra down to 1650Å. Transition region lines in CTTs are broad, very variable, and present blueshifted, centered, and redshifted centroids. Detailed models of the line emission have so far failed to reproduce the fluxes, line shapes, and line ratios. High resolution X-ray line observations indicate the presence of larger amounts of cool plasma in CTTs with respect to WTTs. Observations of density sensitive line ratios of He-like ions suggest high plasma densities, as expected from lines originating in the accretion shock. For most stars, the interpretation of these ratios in terms of density remains equivocal due to the presence of the strong UV continuum.

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“…Kawka et al (2008) refer to the detection of Si IV in the spectra of the hot white dwarfs in the post-common-envelope binaries, Feige 24, EUVE J00720-317, and EUVE J2013+400, and to detection of Si III and Si IV in the spectra of BPM 6502. Some Si III lines have been observed in the spectrum of the rapidly rotating classical T Tauri star RY Tau (Gomez de Castro & Verdugo 2007) and the wind kinematics were derived from the Si III line profiles. The Si III and Si IV ions, as absorbers, have been discovered in the low-z (z < 0.4) intergalactic medium (Danforth & Shull 2008).…”

Section: Introductionmentioning

confidence: 99%

Line broadening in the Si I, Si II, Si III, and Si IV spectra in the helium plasma

Bukvić¹,

Djeniže²,

Srećković³

2009

A&A

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Context. The neutral and ionized silicon spectral line shapes have been investigated in the laboratory helium plasma at electron densities ranging between 3.7 × 10 22 m −3 and 1.1 × 10 23 m −3 and electron temperatures between 12 500 K and 19 000 K, both interesting for astrophysics. Aims. The aim of this work is to present experimental Stark FWHM (full-width at half of the maximum line intensity, W) for number of spectral lines from neutral (Si I), singly (Si II), doubly (Si III), and triply (Si IV) ionized silicon spectra emitted by the pulsed helium discharge, which is optically thin at the wavelengths of the investigated ionic silicon lines. A specific method for estimating self-absorbtion is presented in detail. For investigated Si I spectral lines, applying the proposed method, an optical depth of less than 0.38 is found. Appropriate corrections of the Si I Stark widths were made. The Stark widths of different ionic species, presented in this paper, are measured for the first time in the essentially same laboratory plasma. Methods. The silicon atoms were evaporated from the walls of the specially designed pyrex discharge tube in the pulsed helium discharge at a pressure of 665 Pa in a flowing regime. The Si I, Si II, Si III, and Si IV spectral line profiles were recorded using the McPherson model 209 spectrograph and the Andor ICCD camera as the detection system. Results. The Stark FWHMs of 13 Si I, 15 Si II, 28 Si III, and 9 Si IV spectral lines were measured in the wavelength interval between 206 nm and 640 nm. Five Si I, four Si II, eleven Si III, and one Si IV W values from the above set not had measured or calculated.Our W values are compared with the existing theoretical and experimental data. Conclusions. At the mentioned plasma parameters tolerable agreement was found (within the accuracy of the experiment and uncertainties of the theoretical approaches used) between measured and calculated Stark FWHM values. We recommend the Stark FWHMs of the intense 254.182 nm, 308.624 nm, and 309.342 nm Si III, and 314.956 nm and also 316.571 nm Si IV lines for the plasma diagnostic purposes.

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Evidence of Stellar-driven Outflows from the Classical T Tauri Star RY Tau

Cited by 35 publications

References 12 publications

Nonradial and nonpolytropic astrophysical outflows

Nonradial and nonpolytropic astrophysical outflows

Observations of accretion shocks

Line broadening in the Si I, Si II, Si III, and Si IV spectra in the helium plasma

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