Bow shocks in disks of young binary systems

Fateeva, A. M.; Bisikalo, D. V.; Kaygorodov, P. V.; Sytov, A. Yu.

doi:10.1063/1.4818853

Cited by 2 publications

(2 citation statements)

References 22 publications

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“…Recent 2D and 3D numerical hydrodynamical simulations of mass accretion on to close cTTS binaries (Kaigorodov et al 2010; de Val‐Borro et al 2011; Fateeva et al 2011) suggest that accretion may not directly proceed from the circumbinary disc to the stars; more specifically, they find that local small‐sized discs may develop around both stars, with material flowing from the circumbinary disc to the small discs through the circumbinary gap (and in particular through the co‐rotating outer Lagrange points), and forming a double‐armed spiral structure (with one arm joining each local disc to the wider circumbinary disc) as well as a bridge connecting both local discs. The local discs have predicted sizes similar to those of the corresponding Roche lobes, with radii of ≃3 R ★ in the particular case of V4046 Sgr.…”

Section: Summary and Discussionmentioning

confidence: 99%

The close classical T Tauri binary V4046 Sgr: complex magnetic fields and distributed mass accretion

Donati

Gregory

Montmerle

et al. 2011

Monthly Notices of the Royal Astronomical Society

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We report here the first results of a multi-wavelength campaign focusing on magnetospheric accretion processes within the close binary system V4046 Sgr, hosting two partly convective classical T Tauri stars of masses ≃0.9 Msun and age ≃12 Myr. In this paper, we present time-resolved spectropolarimetric observations collected in 2009 September with ESPaDOnS at the Canada-France-Hawaii Telescope (CFHT) and covering a full span of 7 d or ≃2.5 orbital/rotational cycles of V4046 Sgr. Small circularly polarized Zeeman signatures are detected in the photospheric absorption lines but not in the accretion-powered emission lines of V4046 Sgr, thereby demonstrating that both system components host large-scale magnetic fields weaker and more complex than those of younger, fully convective classical T Tauri stars (cTTSs) of only a few Myr and similar masses.\ud Applying our tomographic imaging tools to the collected data set, we reconstruct maps of the large-scale magnetic field, photospheric brightness and accretion-powered emission at the surfaces of both stars of V4046 Sgr. We find that these fields include significant toroidal components, and that their poloidal components are mostly non-axisymmetric with a dipolar component of 50-100 G strongly tilted with respect to the rotation axis; given the similarity with fields of partly convective main-sequence stars of similar masses and rotation periods, we conclude that these fields are most likely generated by dynamo processes. We also find that both stars in the system show cool spots close to the pole and extended regions of low-contrast, accretion-powered emission; it suggests that mass accretion is likely distributed rather than confined in well-defined high-contrast accretion spots, in agreement with the derived magnetic field complexity

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Section: Summary and Discussionmentioning

confidence: 99%

The close classical T Tauri binary V4046 Sgr: complex magnetic fields and distributed mass accretion

Donati

Gregory

Montmerle

et al. 2011

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Recent 2D and 3D numerical hydrodynamical simulations of mass accretion onto close cTTS binaries (Kaigorodov et al 2010;Fateeva et al 2011;de Val-Borro et al 2011) suggest that accretion may not directly proceed from the circumbinary disc to the stars; more specifically, they find that local small-size discs may develop around both stars, with material flowing from the circumbinary disc to the small discs through the circumbinary gap (and in particular through the co-rotating outer Lagrange points), and forming a double-armed spiral structure (with one arm joining each local disc to the wider circumbinary disc) as well as a bridge connecting both local discs. The local discs have predicted sizes similar to those of the corresponding Roche lobes, with radii of ≃3 R⋆ in the particular case of V4046 Sgr.…”

Section: Summary and Discussionmentioning

confidence: 99%

The close classical T Tauri binary V4046 Sgr: Complex magnetic fields & distributed mass accretion

Donati,

Gregory,

Montmerle

et al. 2011

Preprint

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We report here the first results of a multi-wavelength campaign focussing on magnetospheric accretion processes within the close binary system V4046 Sgr, hosting two partly-convective classical T Tauri stars of masses ≃0.9 M ⊙ and age ≃12 Myr. In this paper, we present time-resolved spectropolarimetric observations collected in 2009 September with ESPaDOnS at the Canada-France-Hawaii Telescope (CFHT) and covering a full span of 7 d or ≃2.5 orbital/rotational cycles of V4046 Sgr. Small circularly polarised Zeeman signatures are detected in the photospheric absorption lines but not in the accretion-powered emission lines of V4046 Sgr, thereby demonstrating that both system components host large-scale magnetic fields weaker and more complex than those of younger, fully-convective cTTSs of only a few Myr and similar masses.Applying our tomographic imaging tools to the collected data set, we reconstruct maps of the large-scale magnetic field, photospheric brightness and accretion-powered emission at the surfaces of both stars of V4046 Sgr. We find that these fields include significant toroidal components, and that their poloidal components are mostly nonaxisymmetric with a dipolar component of 50-100 G strongly tilted with respect to the rotation axis; given the similarity with fields of partly-convective main-sequence stars of similar masses and rotation periods, we conclude that these fields are most likely generated by dynamo processes. We also find that both stars in the system show cool spots close to the pole and extended regions of low-contrast, accretion-powered emission; it suggests that mass accretion is likely distributed rather than confined in well defined high-contrast accretion spots, in agreement with the derived magnetic field complexity.

show abstract

Bow shocks in disks of young binary systems

Cited by 2 publications

References 22 publications

The close classical T Tauri binary V4046 Sgr: complex magnetic fields and distributed mass accretion

The close classical T Tauri binary V4046 Sgr: complex magnetic fields and distributed mass accretion

The close classical T Tauri binary V4046 Sgr: Complex magnetic fields & distributed mass accretion

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