The Close T Tauri Binary System V4046 Sgr: Rotationally Modulated X-Ray Emission from Accretion Shocks
- Author(s)
- Costanza Argiroffi, Antonio Maggio, Thierry Montmerle, David P. Huenemoerder, Evelyne Alecian, Marc Audard, Jerome Bouvier, Francesco Damiani, Jean Francois Donati, Scott G. Gregory, Manuel Güdel, Gaitee A. J. Hussain, Joel H. Kastner, Giuseppe Germano Sacco
- Abstract
We report initial results from a quasi-simultaneous X-ray/optical observing campaign targeting V4046Sgr, a close, synchronous-rotating classical T Tauri star (CTTS) binary in which both components are actively accreting. V4046Sgr is a strong X-ray source, with the X-rays mainly arising from high-density (n e 10 11-10 12 cm -3) plasma at temperatures of 3-4MK. Our multi-wavelength campaign aims to simultaneously constrain the properties of this X-ray-emitting plasma, the large-scale magnetic field, and the accretion geometry. In this paper, we present key results obtained via time-resolved X-ray-grating spectra, gathered in a 360ks XMM-Newton observation that covered 2.2 system rotations. We find that the emission lines produced by this high-density plasma display periodic flux variations with a measured period, 1.22 ± 0.01d, that is precisely half that of the binary star system (2.42d). The observed rotational modulation can be explained assuming that the high-density plasma occupies small portions of the stellar surfaces, corotating with the stars, and that the high-density plasma is not azimuthally symmetrically distributed with respect to the rotational axis of each star. These results strongly support models in which high-density, X-ray-emitting CTTS plasma is material heated in accretion shocks, located at the base of accretion flows tied to the system by magnetic field lines. © 2012. The American Astronomical Society. All rights reserved..
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Università degli Studi di Palermo, INAF Osservatorio Astronomico di Palermo, Université Paris VI - Pierre-et-Marie-Curie, Massachusetts Institute of Technology, Université de recherche Paris Sciences et Lettres, Université de Genève, Observatoire des sciences de l'univers de Grenoble, Observatoire Midi-Pyrénées, California Institute of Technology (Caltech), European Southern Observatory (Germany), Rochester Institute of Technology
- Journal
- The Astrophysical Journal: an international review of astronomy and astronomical physics
- Volume
- 752
- No. of pages
- 17
- ISSN
- 0004-637X
- DOI
- https://doi.org/10.1088/0004-637X/752/2/100
- Publication date
- 2012
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/9c7dcd8b-6b4d-42de-b447-23ce02410e98