Precise orbit solution of MML 53, a low-mass, pre-main sequence eclipsing binary in Upper Centaurus Lupus
Department of Physics and AstronomyVanderbilt University,
2 Summer REU Program, Vanderbilt University, Nashville, Tennessee 37235, USA
3 Astrophysics Research Centre, School of Mathematics & Physics, Queen’s University, University Road, Belfast, BT7 1NN, UK
4 Physics Department, Fisk University, Nashville, Tennessee 37208, USA
5 Department of Physics & Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
Received: 1 December 2010
Accepted: 16 May 2011
Aims. We present a double-lined orbit solution for MML 53, the recently discovered low-mass pre-main sequence eclipsing binary.
Methods. Using high-resolution spectra from the SMARTS 1.5 m echelle spectrograph, we measure precise radial velocities and derive the orbital parameters of the system.
Results. The 2.1 d orbit of the eclipsing pair is circular, and we find the minimum masses of the eclipsing components to be M1sin3i = 0.97 M⊙ and M2sin3i = 0.84 M⊙, with formal uncertainties of 2.0% and an additional systematic uncertainty of ≈2.5% most likely caused by large star spots on the primary star. MML 53 has been previously identified as a member of the Upper Centaurus Lupus (UCL) star forming region (age ~15 Myr). The systemic radial velocity from our orbit solution, vγ = +1.4 ± 0.3 ± 0.8 km s-1 (statistical and systematic), is also consistent with kinematic membership in this association. In addition, we detect a change in vγ between 2006 and 2009 providing further evidence for the presence of a the third body in a wide (several year) orbit.
Key words: binaries: eclipsing / stars: pre-main sequence / binaries: spectroscopic / stars: fundamental parameters / stars: individual: MML 53
© ESO, 2011