A triple star in disarray

Multi-epoch observations of T Tauri with VLT-SPHERE and LBT-LUCI

¹ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
e-mail: mkasper@eso.org
² Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
³ INAF–Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁴ Max-Planck-Institute for Astronomy (MPIA), Königstuhl 17, 69117 Heidelberg, Germany
⁵ CRAL, CNRS, Université Lyon 1, Université de Lyon, ENS, 9 avenue Charles Andre, 69561 Saint Genis Laval, France
⁶ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
⁷ Anton Pannekoek Institute for Astronomy, Science Park 9, 1098XH Amsterdam, The Netherlands
⁸ DOTA, ONERA, Université Paris Saclay, 91123, Palaiseau France
⁹ Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France
¹⁰ Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
¹¹ Escuela de Ingeniería Industrial, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
¹² LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, 92195 Meudon, France
¹³ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago, Chile
¹⁴ Geneva Observatory, University of Geneva, Chemin des Mailettes 51, 1290 Versoix, Switzerland
¹⁵ Department of Astrophysics, University of Vienna, Türkenschanzstr. 17 (Sternwarte), 1180 Vienna, Austria
¹⁶ Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany
¹⁷ INAF - Catania Astrophysical Observatory, via S. Sofia 78, 95123 Catania, Italy

Received: 14 August 2020
Accepted: 20 October 2020

Abstract

Aims. T Tauri remains an enigmatic triple star for which neither the evolutionary state of the stars themselves, nor the geometry of the complex outflow system is completely understood. Eight-meter class telescopes equipped with state-of-the-art adaptive optics provide the spatial resolution necessary to trace tangential motion of features over a timescale of a few years, and they help to associate them with the different outflows.

Methods. We used J-, H-, and K-band high-contrast coronagraphic imaging with VLT-SPHERE recorded between 2016 and 2018 to map reflection nebulosities and obtain high precision near-infrared (NIR) photometry of the triple star. We also present H₂ emission maps of the ν = 1-0 S(1) line at 2.122 μm obtained with LBT-LUCI during its commissioning period at the end of 2016.

Results. The data reveal a number of new features in the system, some of which are seen in reflected light and some are seen in H₂ emission; furthermore, they can all be associated with the main outflows. The tangential motion of the features provides compelling evidence that T Tauri Sb drives the southeast–northwest outflow. T Tauri Sb has recently faded probably because of increased extinction as it passes through the southern circumbinary disk. While Sb is approaching periastron, T Tauri Sa instead has brightened and is detected in all our J-band imagery for the first time.