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Magnetospheric accretion in the intermediate-mass T Tauri star HQ Tauri

Pouilly, K. and Bouvier, J. and Alecian, E. and Alencar, S. H. P. and Cody, A.-M. and Donati, J.-F. and Grankin, K. and Hussain, G. A. J. and Rebull, L. and Folsom, C. P. (2020) Magnetospheric accretion in the intermediate-mass T Tauri star HQ Tauri. Astronomy and Astrophysics, 642 . Art. No. A99. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:20201008-083809651

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Abstract

Context. Classical T Tauri stars are pre-main sequence stars surrounded by an accretion disk. They host a strong magnetic field, and both magnetospheric accretion and ejection processes develop as the young magnetic star interacts with its disk. Studying this interaction is a major goal toward understanding the properties of young stars and their evolution. Aims. The goal of this study is to investigate the accretion process in the young stellar system HQ Tau, an intermediate-mass T Tauri star (1.9 M_⊙). Methods. The time variability of the system is investigated both photometrically, using Kepler-K2 and complementary light curves, and from a high-resolution spectropolarimetric time series obtained with ESPaDOnS at CFHT. Results. The quasi-sinusoidal Kepler-K2 light curve exhibits a period of 2.424 d, which we ascribe to the rotational period of the star. The radial velocity of the system shows the same periodicity, as expected from the modulation of the photospheric line profiles by surface spots. A similar period is found in the red wing of several emission lines (e.g., HI, CaII, NaI), due to the appearance of inverse P Cygni components, indicative of accretion funnel flows. Signatures of outflows are also seen in the line profiles, some being periodic, others transient. The polarimetric analysis indicates a complex, moderately strong magnetic field which is possibly sufficient to truncate the inner disk close to the corotation radius, r_(cor) ∼ 3.5 R_★. Additionally, we report HQ Tau to be a spectroscopic binary candidate whose orbit remains to be determined. Conclusions. The results of this study expand upon those previously reported for low-mass T Tauri stars, as they indicate that the magnetospheric accretion process may still operate in intermediate-mass pre-main sequence stars, such as HQ Tauri.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1051/0004-6361/202038086DOIArticle
https://arxiv.org/abs/2008.12531arXivDiscussion Paper
ORCID:
AuthorORCID
Pouilly, K.0000-0002-9628-2959
Bouvier, J.0000-0002-7450-6712
Rebull, L.0000-0001-6381-515X
Additional Information:© K. Pouilly et al. 2020. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 3 April 2020 / Accepted 3 August 2020. We thank an anonymous referee whose comments improved the content of this paper. We thank Lynne Hillenbrand and Hervé Bouy for taking additional high resolution spectra of HQ Tau that helped us assessing its binary nature. We acknowledge with thanks the variable star observations from the AAVSO International Database contributed by observers worldwide and used in this research. This paper includes data collected by the Kepler mission. Funding for the Kepler mission is provided by the NASA Science Mission directorate. This work has made use of the VALD database, operated at Uppsala University, the Institute of Astronomy RAS in Moscow, and the University of Vienna. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No 742095; SPIDI: Star-Planets-Inner Disk- Interactions; http://www.spidi-eu.org). This project was funded in part by INSU/CNRS Programme National de Physique Stellaire and Observatoire de Grenoble Labex OSUG2020. S.H.P. Alencar acknowledges financial support from CNPq, CAPES and Fapemig.
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
European Research Council (ERC)742095
Star-Planets-Inner Disk-Interactions (SPIDI)UNSPECIFIED
Institut national des sciences de l'Univers (INSU)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Observatoire des Sciences de l'Univers de Grenoble (OSUG)UNSPECIFIED
LabExOSUG2020
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
Subject Keywords:stars: variables: T Tauri, Herbig Ae/Be / stars: pre-main sequence / accretion, accretion disks / stars: magnetic field / stars: individual: HQ Tau / starspots
Record Number:CaltechAUTHORS:20201008-083809651
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20201008-083809651
Official Citation:Magnetospheric accretion in the intermediate-mass T Tauri star HQ Tauri K. Pouilly, J. Bouvier, E. Alecian, S. H. P. Alencar, A.-M. Cody, J.-F. Donati, K. Grankin, G. A. J. Hussain, L. Rebull and C. P. Folsom A&A, 642 (2020) A99 DOI: https://doi.org/10.1051/0004-6361/202038086
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105916
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:08 Oct 2020 18:05
Last Modified:08 Oct 2020 18:05

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