On the formation of H  line emission around classical T Tauri stars

Kurosawa, Ryuichi; Harries, Tim J.; Symington, Neil H.

doi:10.1111/j.1365-2966.2006.10527.x

Cited by 190 publications

(296 citation statements)

References 75 publications

Supporting

Mentioning

281

Contrasting

Unclassified

Order By: Relevance

“…Theoretical emission-line profiles of CTTSs have often been computed in the literature and compared to the observations to determine the main characteristics of the circumstellar accretion flow of these objects (Muzerolle et al 1998(Muzerolle et al , 2001Kurosawa et al 2006). However, the steady-state axisymmetric dipolar models that are more commonly used to describe the stellar magnetosphere cannot reproduce the variability observed in the emission profiles of CTTSs.…”

Section: Theoretical Line Profilesmentioning

confidence: 99%

“…None of our theoretical models have included a wind component, which is expected to be present in these systems, even if it does not always contribute significantly to the line profile (Kurosawa et al 2006;Lima et al 2010). There are some blueshifted features, such as a shoulder, in the observed Hα profiles that could be due either to an absorption, coming from a wind, or to an emission excess, from different projections of the accretion funnel.…”

Section: Theoretical Line Profilesmentioning

confidence: 99%

“…These distributions were mapped on to the radiative transfer grid of the TORUS code (Harries 2000;Kurosawa et al 2006Kurosawa et al , 2011, and the corresponding line source functions were calculated. The theoretical profiles of Hα and Hβ were computed using the Sobolev escape probability method, as described in Klein & Castor (1978) and Hartmann et al (1994).…”

Section: Theoretical Line Profilesmentioning

confidence: 99%

“…Magnetospheric accretion models have been successful in explaining most of the observed This work uses observations made with the HARPS instrument at the 3.6-m ESO telescope (La Silla, Chile) in the framework of the LP182.D-0356. characteristics of CTTSs (Shu et al 1994;Hartmann et al 1994;Muzerolle et al 2001;Kurosawa et al 2006;Lima et al 2010) and are currently the most accepted ways to describe these systems. In the past decade, magnetohydrodynamic (MHD) simulations have followed the rotational evolution of CTTSs over as many as hundreds of rotational periods, presenting a dynamical view of the star-disk interaction (Goodson et al 1999;Romanova et al 2002;Long et al 2008;Zanni & Ferreira 2009) that can be tested with synoptic observations.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Accretion dynamics in the classical T Tauri star V2129 Ophiuchi

Alencar

Bouvier

Walter

et al. 2012

A&A

Self Cite

110

View full text Add to dashboard Cite

Context. Classical T Tauri stars are variable objects on several timescales, but just a few of them have been studied in detail, with different observational techniques and over many rotational cycles to enable the analysis of the stellar and circumstellar variations on rotational timescales. Aims. We test the dynamical predictions of the magnetospheric accretion model with synoptic data of the classical T Tauri star V2129 Oph obtained over several rotational cycles. Methods. We analyze high resolution observations obtained with the HARPS, ESPaDOnS, and SMARTS spectrographs and simultaneous photometric measurements, clearly sampling four rotational cycles, and fit them with cold/hot spot models and radiative transfer models of emission lines. Results. The photometric variability and the radial velocity variations in the photospheric lines can be explained by the rotational modulation due to cold spots, while the radial velocity variations of the He i (5876 Å) line and the veiling variability are due to hot spot rotational modulation. The hot and cold spots are located at high latitudes and about the same phase, but the hot spot is expected to sit at the chromospheric level, while the cold spot is at the photospheric level. The mass-accretion rate of the system is stable overall around (1.5 ± 0.6) × 10 −9 M yr −1 , but can increase by three times this value in a rotational cycle, during an accretion burst. The Hα and Hβ emission-line profiles vary substantially and are well-reproduced by radiative transfer models calculated from the funnel flow structure of three-dimensional magnetohydrodynamic simulations, using the dipole+octupole magnetic-field configuration previously proposed for the system. Our diskwind models do not provide a significant contribution to the emission or absorption Hα line profile of V2129 Oph. Conclusions. The global scenario proposed by magnetospheric accretion for classical T Tauri stars is able to reproduce the spectroscopic and photometric variability observed in V2129 Oph.

show abstract

Section: Theoretical Line Profilesmentioning

confidence: 99%

Section: Theoretical Line Profilesmentioning

confidence: 99%

Section: Theoretical Line Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Accretion dynamics in the classical T Tauri star V2129 Ophiuchi

Alencar

Bouvier

Walter

et al. 2012

A&A

Self Cite

110

View full text Add to dashboard Cite

show abstract

“…These differences establish that the physical conditions change along the accretion flow, which opens a rare opportunity to study the structure and physical conditions in the accretion flow.The temperature and density profiles along the accretion flows have not been inferred from observations before, and are known only as parameters derived from standard models of magnetospheric accretion (e.g., Hartmann et al 1994;Martin 1996;Muzerolle et al 2001;Kurosawa et al 2006). Here, we estimate these parameters directly from the spectra of the infalling gas.…”

Section: Shapes and Strengths Of Inverse P Cygni Profilesmentioning

confidence: 99%

Doppler probe of accretion onto a T Tauri star

Петров¹,

Gahm²,

Herczeg³

et al. 2014

A&A

View full text Add to dashboard Cite

Context. The YY Ori stars are T Tauri stars with prominent time-variable redshifted absorption components that flank certain emission lines. S CrA, one of the brightest of these stars, affords the rare opportunity of directly probing the accretion processes on the line of sight to one of the components of this wide visual pair. Aims. We followed the spectral changes in S CrA to derive the physical structure of the accreting gas. Methods. A series of high-resolution spectra of the two components of S CrA was obtained during four nights with the UVES spectrograph at the Very Large Telescope. Results. We found that both stars are very similar with regard to surface temperature, radius, and mass. Variable redshifted absorption components are particularly prominent in the SE component. During one night, this star developed a spectrum unique among the T Tauri stars: extremely strong and broad redshifted absorption components appeared in many lines of neutral and ionized metals, in addition to those of hydrogen and helium. The absorption depths of cooler, low-ionization lines peak at low velocities -while more highly ionized lines have peak absorption depths at high velocities. The different line profiles indicate that the temperature and density of the accretion stream increase as material approaches the star. We derive the physical conditions of the flow at several points along the accretion funnel directly from the spectrum of the infalling gas. We estimated mass accretion rates of about 10 −7 M /yr, which is similar to that derived from the relation based on the strength of Hα emission line. Conclusions. This is the first time the density and temperature distributions in accretion flows around a T Tauri star have been inferred from observations. Compared with predictions from standard models of accretion in T Tauri stars, which assume a dipole stellar magnetic field, we obtained higher densities and a steeper temperature rise toward the star.

show abstract

Analytic and numerical models of the 3D multipolar magnetospheres of pre‐main sequence stars

Gregory

Donati

2011

Astron Nachr

View full text Add to dashboard Cite

Traditionally models of accretion of gas on to T Tauri stars have assumed a dipole stellar magnetosphere, partly for simplicity, but also due to the lack of information about their true magnetic field topologies. Before and since the first magnetic maps of an accreting T Tauri star were published in 2007 a new generation of magnetospheric accretion models have been developed that incorporate multipole magnetic fields. Three-dimensional models of the large-scale stellar magnetosphere with an observed degree of complexity have been produced via numerical field extrapolation from observationally derived T Tauri magnetic maps. Likewise, analytic and magnetohydrodynamic models with multipolar stellar magnetic fields have been produced. In this conference review article we compare and contrast the numerical field extrapolation and analytic approaches, and argue that the large-scale magnetospheres of some (but not all) accreting T Tauri stars can be well described by tilted dipole plus tilted octupole field components. We further argue that the longitudinal field curve, whether derived from accretion related emission lines, or from photospheric absorption lines, provides poor constrains on the large-scale magnetic field topology and that detailed modeling of the rotationally modulated Stokes V signal is required to recover the true field complexity. We conclude by examining the advantages, disadvantages and limitations of both the field extrapolation and analytic approaches, and also those of magnetohydrodynamic models.

show abstract

On the formation of H line emission around classical T Tauri stars

Cited by 190 publications

References 75 publications

Accretion dynamics in the classical T Tauri star V2129 Ophiuchi

Accretion dynamics in the classical T Tauri star V2129 Ophiuchi

Doppler probe of accretion onto a T Tauri star

Analytic and numerical models of the 3D multipolar magnetospheres of pre‐main sequence stars

Contact Info

Product

Resources

About