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
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