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Investigating the magnetospheric accretion process in the young pre-transitional disk system DoAr 44 (V2062 Oph). A multiwavelength interferometric, spectropolarimetric, and photometric observing campaign

Bouvier, J. and Alecian, E. and Alencar, S. H. P. and Sousa, A. and Donati, J.-F. and Perraut, K. and Bayo, A. and Rebull, L. M. and Dougados, C. and Duvert, G. and Berger, J.-P. and Benisty, M. and Pouilly, K. and Folsom, C. P. and Moutou, C. (2020) Investigating the magnetospheric accretion process in the young pre-transitional disk system DoAr 44 (V2062 Oph). A multiwavelength interferometric, spectropolarimetric, and photometric observing campaign. Astronomy and Astrophysics, 643 . Art. No. A99. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:20201012-073512305

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Abstract

Context. Young stars interact with their accretion disk through their strong magnetosphere. Aims. We aim to investigate the magnetospheric accretion/ejection process in the young stellar system DoAr 44 (V2062 Oph). Methods. We monitored the system over several rotational cycles, combining high-resolution spectropolarimetry at both optical and near-IR wavelengths with long-baseline near-IR inteferometry and multicolor photometry. Results. We derive a rotational period of 2.96 d from the system’s light curve, which is dominated by stellar spots. We fully characterize the central star’s properties from the high signal-to-noise, high-resolution optical spectra we obtained during the campaign. DoAr 44 is a young 1.2 M_⊙ star, moderately accreting from its disk (Ṁ_(acc) = 6.5 10⁻⁹ M_⊙ yr⁻¹), and seen at a low inclination (i ≃ 30°). Several optical and near-IR line profiles probing the accretion funnel flows (Hα, Hβ, HeI 1083 nm, Paβ) and the accretion shock (HeI 587.6 nm) are modulated at the stellar rotation period. The most variable line profile is HeI 1083 nm, which exhibits modulated redshifted wings that are a signature of accretion funnel flows, as well as deep blueshifted absorptions indicative of transient outflows. The Zeeman-Doppler analysis suggests the star hosts a mainly dipolar magnetic field, inclined by about 20° onto the spin axis, with an intensity reaching about 800 G at the photosphere, and up to 2 ± 0.8 kG close to the accretion shock. The magnetic field appears strong enough to disrupt the inner disk close to the corotation radius, at a distance of about 4.6 R⋆ (0.043 au), which is consistent with the 5 R⋆ (0.047 au) upper limit we derived for the size of the magnetosphere in our Paper I from long baseline interferometry. Conclusions. DoAr 44 is a pre-transitional disk system, exhibiting a 25–30 au gap in its circumstellar disk, with the inner and outer disks being misaligned. On a scale of 0.1 au or less, our results indicate that the system is steadily accreting from its inner disk through its tilted dipolar magnetosphere. We conclude that in spite of a highly structured disk on the large scale, perhaps the signature of ongoing planetary formation, the magnetospheric accretion process proceeds unimpeded at the star-disk interaction level.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1051/0004-6361/202038892DOIArticle
https://arxiv.org/abs/2010.00887arXivDiscussion Paper
ORCID:
AuthorORCID
Bouvier, J.0000-0002-7450-6712
Alencar, S. H. P.0000-0002-5171-8376
Sousa, A.0000-0001-7397-8972
Bayo, A.0000-0001-7868-7031
Rebull, L. M.0000-0001-6381-515X
Duvert, G.0000-0001-8769-3660
Berger, J.-P.0000-0001-5025-0428
Benisty, M.0000-0002-7695-7605
Pouilly, K.0000-0002-9628-2959
Moutou, C.0000-0002-2842-3924
Additional Information:© J. Bouvier et al. 2020. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Received: 10 July 2020; Accepted: 10 September 2020. Published online 09 November 2020. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 0103.C-0097, and at the Las Cumbres Observatory global telescope network (LCOGT). We gratefully acknowledge the help from Tim Brown at LCOGT for obtaining test images and from LCOGT support service for scheduling and data reduction. We thank the very efficient QSO team at CFHT. This study is based in part on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. The observations at the Canada-France-Hawaii Telescope were performed with care and respect from the summit of Maunakea, which is a significant cultural and historic site. This publication is based in part on data obtained under CNTAC program CLN2019B-004. This publication is based in part on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 0103.C-0097. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. SHPA acknowledges financial support from CNPq, CAPES, Fapemig, and Cofecub. A. B. acknowledges support from FONDECYT Grant 1190748 and from ICM (Iniciativa Científica Milenio) via the Núcleo Milenio de Formación Planetaria grant. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742095; SPIDI: Star-Planets-Inner Disk-Interactions, http://www.spidi-eu.org, and Grant agreement No. 740651 NewWorlds).
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
Gaia Multilateral AgreementUNSPECIFIED
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNSPECIFIED
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)UNSPECIFIED
Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)UNSPECIFIED
French Committee for the Evaluation of Academic and Scientific Cooperation with Brazil (COFECUB)UNSPECIFIED
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1190748
Iniciativa Científica MilenioUNSPECIFIED
Núcleo Milenio de Formación PlanetariaUNSPECIFIED
European Research Council (ERC)742095
European Research Council (ERC)740651
Subject Keywords:stars: pre-main sequence – stars: variables: T Tauri, Herbig Ae/Be – stars: magnetic field – stars: formation – accretion, accretion disks
Record Number:CaltechAUTHORS:20201012-073512305
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20201012-073512305
Official Citation:Investigating the magnetospheric accretion process in the young pre-transitional disk system DoAr 44 (V2062 Oph) - A multiwavelength interferometric, spectropolarimetric, and photometric observing campaign. J. Bouvier, E. Alecian, S. H. P. Alencar, A. Sousa, J.-F. Donati, K. Perraut, A. Bayo, L. M. Rebull, C. Dougados, G. Duvert, J.-P. Berger, M. Benisty, K. Pouilly, C. Folsom, C. Moutou and the SPIRou consortium. A&A, 643 (2020) A99; DOI: https://doi.org/10.1051/0004-6361/202038892
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105977
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:12 Oct 2020 15:33
Last Modified:11 Nov 2020 16:44

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