Protostars and Planets V 2005 8398.pdf GW ORIONIS: A T-TAURI MULTIPLE SYSTEM OBSERVED WITH AU-SCALE RESOLUTION. J. P.Berger, Laboratoire d’Astrophysique de Grenoble,, BP-53, F-38041 Grenoble Cedex, France,
[email protected], J. Monnier, E. Pedretti, University of Michigan, , Ann Arbor, MI 48109-1090. USA , R. Millan-Gabet, California Institute of Technology, Pasadena, CA 91125, USA, F. Malbet, K. Perraut, P. Kern, M. Benisty, P. Haguenauer, Laboratoire d’Astrophysique de Grenoble, F-38041 Grenoble Cedex, France, P. Labeye, CEA-LETI 38054 Grenoble, Cedex, France, W. Traub, N. Carleton, M. Lacasse, Harvard Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA, S. Meimon, ONERA, Chatillon, France, C. Brechet, E. Thiebaut, CRAL, Lyon, France, P.Schloerb, University of Massachusetts at Amherst, Astronomy Department, Amherst, MA 01003, USA. GW Orionis is a well known single-line spectroscopic bi- 3 instrument which allows to measure simultaneously 3 vis- nary classified as a T Tauri star. The measured period is ≈ 242 ibilities and one closure phase (Monnier et al. 2004). The days. The stars are separated by ≈ 1.1AU and have a nearly addition of several measurements at different hour angle and circular orbit. The analysis of the residuals have revealed the two IOTA configuration allowed a map of the (u,v) plane suf- signature of a putative third companion with orbital period ficient to carry out the first reconstruction of an image of a T ≈ 1000 days. Tauri star with Astronomical Unit resolution (see Figure 1). The combination of spectroscopic measurements and spec- A detailed analysis of visibilities and closure phases is tral energy distribution modelization has lead Mathieu et al.(1991) however preferable if one is to quantify the system parameters to describe GW Orionis as a primary star surrounded with a cir- with a certain accuracy (see Figure 2).