Precise orbit solution of MML 53, a low-mass, pre-main sequence eclipsing binary in Upper Centaurus Lupus

• 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 M(1) sin(3) i = 0.97 M(circle dot) and M(2) sin(3) i = 0.84 M(circle dot), with formal uncertainties of 2.0% and an additional systematic uncertainty of approximate to 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 similar to 15 Myr). The systemic radial velocity from our orbit solution, v(gamma) = + 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 v(gamma) between 2006 and 2009 providing further evidence for the presence of a the third body in a wide (several year) orbit.

Ämnesord

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Nyckelord

binaries: eclipsing

stars: pre-main sequence

binaries: spectroscopic

stars: fundamental parameters

stars: individual: MML 53

Physics

Fysik

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