The GRAVITY young stellar object survey: V. The orbit of the T Tauri binary star WW Cha


Por: Eupen F., Labadie L., Grellmann R., Perraut K., Brandner W., Duchêne G., Köhler R., Sanchez-Bermudez J., Garcia Lopez R., Caratti O Garatti A., Benisty M., Dougados C., Garcia P., Klarmann L., Amorim A., Bauböck M., Berger J.P., Caselli P., Clénet Y., Coudé Du Foresto V., De Zeeuw P.T., Drescher A., Duvert G., Eckart A., Eisenhauer F., Filho M., Ganci V., Gao F., Gendron E., Genzel R., Gillessen S., Heissel G., Henning T., Hippler S., Horrobin M., Hubert Z., Jiménez-Rosales A., Jocou L., Kervella P., Lacour S., Lapeyrère V., Le Bouquin J.B., Léna P., Ott T., Paumard T., Perrin G., Pfuhl O., Rodríguez-Coira G., Rousset G., Scheithauer S., Shangguan J., Shimizu T., Stadler J., Straub O., Straubmeier C., Sturm E., Van DIshoeck E., Vincent F., Von Fellenberg S.D., Widmann F., Woillez J., Wojtczak A.

Publicada: 1 ene 2021
Resumen:
Context. Close young binary stars are unique laboratories for the direct measurement of pre-main-sequence (PMS) stellar masses and their comparison to evolutionary theoretical models. At the same time, a precise knowledge of their orbital parameters when still in the PMS phase offers an excellent opportunity for understanding the influence of dynamical effects on the morphology and lifetime of the circumstellar as well as circumbinary material. Aims. The young T Tauri star WW Cha was recently proposed to be a close binary object with strong infrared and submillimeter excess associated with circum-system emission, which makes it dynamically a very interesting source in the above context. The goal of this work is to determine the astrometric orbit and the stellar properties of WW Cha using multi-epoch interferometric observations. Methods. We derive the relative astrometric positions and flux ratios of the stellar companion in WW Cha from the interferometric model fitting of observations made with the VLTI instruments AMBER, PIONIER, and GRAVITY in the near-infrared from 2011 to 2020. For two epochs, the resulting uv-coverage in spatial frequencies permits us to perform the first image reconstruction of the system in the K band. The positions of nine epochs are used to determine the orbital elements and the total mass of the system. Combining the orbital solution with distance measurements from Gaia DR2 and the analysis of evolutionary tracks, we constrain the mass ratio. Results. We find the secondary star orbiting the primary with a period of T = 206.55 days, a semimajor axis of a = 1.01 au, and a relatively high eccentricity of e = 0.45. The dynamical mass of Mtot = 3.20 Mpdbl can be explained by a mass ratio between ~0.5 and 1, indicating an intermediate-mass T Tauri classification for both components. The orbital angular momentum vector is in close alignment with the angular momentum vector of the outer disk as measured by ALMA and SPHERE, resulting in a small mutual disk inclination. The analysis of the relative photometry suggests the presence of infrared excess surviving in the system and likely originating from truncated circumstellar disks. The flux ratio between the two components appears variable, in particular in the K band, and may hint at periods of triggered higher and lower accretion or changes in the disks' structures. Conclusions. The knowledge of the orbital parameters, combined with a relatively short period, makes WW Cha an ideal target for studying the interaction of a close young T Tauri binary with its surrounding material, such as time-dependent accretion phenomena. Finding WW Cha to be composed of two (probably similar) stars led us to reevaluate the mass of WW Cha, which had been previously derived under the assumption of a single star. This work illustrates the potential of long baseline interferometry to precisely characterize close young binary stars separated by a few astronomical units. Finally, when combined with radial velocity measurements, individual stellar masses can be derived and used to calibrate theoretical PMS models. © ESO 2021.

Filiaciones:
Eupen F.:
 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Str. 77, Koln, 50937, Germany

Labadie L.:
 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Str. 77, Koln, 50937, Germany

Grellmann R.:
 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Str. 77, Koln, 50937, Germany

Perraut K.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Brandner W.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

Duchêne G.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

 Astronomy Department, University of California, Berkeley, CA 94720-3411, United States

Köhler R.:
 University of Vienna, Department of Astrophysics, Türkenschanzstr. 17, Vienna, 1180, Austria

Sanchez-Bermudez J.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

 Instituto de Astronomiá, Universidad Nacional Autónoma de México, Apdo. Postal 70264, Ciudad de México, 04510, Mexico

Garcia Lopez R.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

 Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin, D02 XF86, Ireland

 School of Physics, University College Dublin, Belfield, Dublin 4, Ireland

Caratti O Garatti A.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

 Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin, D02 XF86, Ireland

 School of Physics, University College Dublin, Belfield, Dublin 4, Ireland

Benisty M.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

 Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS UMI 3386), Departamento de Astronomía, Universidad de Chile, Camino El Observatorio, Las Condes, Santiago, 1515, Chile

Dougados C.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Garcia P.:
 CENTRA, Centro de Astrofisica e Gravitacao, Instituto Superior Tecnico, Avenida Rovisco Pais 1, Lisboa, 1049, Portugal

 Universidade Do Porto, Faculdade de Engenharia, Rua Dr. Roberto Frias, Porto, 4200-465, Portugal

Klarmann L.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

Amorim A.:
 CENTRA, Centro de Astrofisica e Gravitacao, Instituto Superior Tecnico, Avenida Rovisco Pais 1, Lisboa, 1049, Portugal

 Universidade de Lisboa - Faculdade de Ciencias, Campo Grande, Lisboa, 1749-016, Portugal

Bauböck M.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Berger J.P.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Caselli P.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Clénet Y.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Coudé Du Foresto V.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

De Zeeuw P.T.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

 Sterrewacht Leiden, Leiden University, Postbus 9513, Leiden, 2300 RA, Netherlands

Drescher A.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Duvert G.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Eckart A.:
 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Str. 77, Koln, 50937, Germany

 Max-Planck-Institute for Radio Astronomy, Auf dem Hügel 69, Bonn, 53121, Germany

Eisenhauer F.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Filho M.:
 CENTRA, Centro de Astrofisica e Gravitacao, Instituto Superior Tecnico, Avenida Rovisco Pais 1, Lisboa, 1049, Portugal

 Universidade Do Porto, Faculdade de Engenharia, Rua Dr. Roberto Frias, Porto, 4200-465, Portugal

Ganci V.:
 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Str. 77, Koln, 50937, Germany

Gao F.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Gendron E.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Genzel R.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Gillessen S.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Heissel G.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Henning T.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

Hippler S.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

Horrobin M.:
 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Str. 77, Koln, 50937, Germany

Hubert Z.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Jiménez-Rosales A.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Jocou L.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Kervella P.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Lacour S.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Lapeyrère V.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Le Bouquin J.B.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Léna P.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Ott T.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Paumard T.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Perrin G.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Pfuhl O.:
 European Southern Observatory, Karl-Schwarzschild-Str. 2, Garching, 85748, Germany

Rodríguez-Coira G.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Rousset G.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Scheithauer S.:
 Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg, 69117, Germany

Shangguan J.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Shimizu T.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Stadler J.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Straub O.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Straubmeier C.:
 Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, 38000, France

Sturm E.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Van DIshoeck E.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

 Sterrewacht Leiden, Leiden University, Postbus 9513, Leiden, 2300 RA, Netherlands

Vincent F.:
 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universites, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cite, Paris, France

Von Fellenberg S.D.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Widmann F.:
 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Garching bei Munchen, 85741, Germany

Woillez J.:
 European Southern Observatory, Karl-Schwarzschild-Str. 2, Garching, 85748, Germany

Wojtczak A.:
 I. Physikalisches Institut, Universitat zu Koln, Zulpicher Str. 77, Koln, 50937, Germany
ISSN: 00046361
Editorial
EDP SCIENCES S A, 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE, Francia
Tipo de documento: Article
Volumen: 648 Número:
Páginas:
WOS Id: 000639365600012
imagen

MÉTRICAS