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Star-disk interacti...
Star-disk interactions in the strongly accreting T Tauri star S CrA N
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- Nowacki, H. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Alecian, E. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Perraut, K. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Zaire, B. (författare)
- Univ Fed Minas Gerais, Dept Fis, BR-31270901 Belo Horizonte, MG, Brazil.
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- Folsom, C. P. (författare)
- Univ Tartu, Fac Sci & Technol, Tartu Observ, EE-51003 Tartu, Estonia.
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- Pouilly, Kim (författare)
- Uppsala universitet,Institutionen för fysik och astronomi
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- Bouvier, J. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Manick, R. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Pantolmos, G. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Sousa, A. P. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Dougados, C. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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- Hussain, G. A. J. (författare)
- European Space Res & Technol Ctr ESA ESTEC, Sci Div, Directorate Sci, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
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- Alencar, S. H. P. (författare)
- Univ Fed Minas Gerais, Dept Fis, BR-31270901 Belo Horizonte, MG, Brazil.
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- Le Bouquin, J. B. (författare)
- Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France.
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Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France Univ Fed Minas Gerais, Dept Fis, BR-31270901 Belo Horizonte, MG, Brazil. (creator_code:org_t)
- EDP Sciences, 2023
- 2023
- Engelska.
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 678
- Relaterad länk:
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https://doi.org/10.1...
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https://uu.diva-port... (primary) (Raw object)
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Context. Classical T Tauri Stars are thought to accrete material from their surrounding protoplanetary disks through funnel flows along their magnetic field lines. Among them, those with high accretion rates (similar to 10(-7)M(circle dot) yr(-1) ) are ideal targets to test this magnetospheric accretion scenario in a sustained regime.Aims. We aimed at constraining the accretion-ejection phenomena around the strongly-accreting Northern component of the S CrA young binary system (S CrA N) by deriving its magnetic field topology and its magnetospheric properties, and by detecting ejection signatures, if any.Methods. We led a two-week observing campaign on S CrA N with the ESPaDOnS optical spectropolarimeter at the Canada-FranceHawaii Telescope. We recorded 12 Stokes I and V spectra over 14 nights. We computed the corresponding Least-Square Deconvolution (LSD) profiles of the photospheric lines and performed Zeeman-Doppler Imaging (ZDI). We analysed the kinematics of noticeable emission lines, namely He I lambda 5876 and the four first lines of the Balmer series, known to trace the accretion process. Results. We found that S CrA N is a low-mass (0.8 M-circle dot), young (similar to 1 Myr), and fully convective object exhibiting a strong and variable veiling (with a mean value of 7 +/- 2), which suggests that the star is in a strong accretion regime. These findings could indicate a stellar evolutionary stage between Class I and Class II for S CrA N. We reconstructed an axisymmetric large-scale magnetic field (similar to 70% of the total energy), primarily located in the dipolar component but with significant higher poloidal orders. From the He I lambda 5876 narrow emission component radial velocity curve, we derived a stellar rotation period of P-& lowast; = 7.3 +/- 0.2 days. We found a magnetic truncation radius of similar to 2 R-& lowast; which is significantly closer to the star than the corotation radius of similar to 6 R-& lowast;, suggesting that S CrA N is in an unstable accretion regime. The truncation radius being quite smaller than the size of the Br gamma line emitting region, as measured with the GRAVITY interferometer (similar to 8 R-& lowast;), supports the presence of outflows, which is nicely corroborated by the line profiles presented in this work.Conclusions. The findings from spectropolarimetry are complementary to those provided by optical long-baseline interferometry, allowing us to construct a coherent view of the innermost regions of a young, strongly accreting star. Yet, the strong and complex magnetic field reconstructed for S CrA N is inconsistent with the observed magnetic signatures of the emission lines associated to the post-shock region. We recommend a multi-technique, synchronized campaign of several days to put more constrains on a system that varies on a similar to 1 day timescale.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
Nyckelord
- stars: variables: T Tauri
- Herbig Ae/Be
- stars: individual: S CrA N
- stars: magnetic field
- techniques: spectroscopic
- techniques: polarimetric
- accretion
- accretion disks
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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- Av författaren/redakt...
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Nowacki, H.
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Alecian, E.
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Perraut, K.
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Zaire, B.
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Folsom, C. P.
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Pouilly, Kim
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visa fler...
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Bouvier, J.
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Manick, R.
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Pantolmos, G.
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Sousa, A. P.
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Dougados, C.
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Hussain, G. A. J ...
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Alencar, S. H. P ...
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Le Bouquin, J. B ...
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