Robotic observations of the most eccentric spectroscopic binary in the sky

2013 
Context. The visual A component of the Gliese 586AB system is a double-lined spectroscopic binary consisting of two cool stars with the exceptional orbital eccentricity of 0.976. Such an extremely eccentric system may be important for our understanding of low-mass binary formation. Aims. Precise stellar masses, ages, orbital elements, and rotational periods are a prerequisite for comparing stellar observations to angular-momentum evolution models. Methods. We present a total of 598 high-resolution echelle spectra from our robotic facility STELLA from 2006–2012, which we used to compute orbital elements of unprecedented accuracy. New Johnson VI photometry for the two visual components is also presented. Results. Our double-lined orbital solution for the A system has average velocity residuals for a measure of unit weight of 41 m s −1 for the G9V primary and 258 m s −1 for the M0V secondary, better by a factor ≈10 than the discovery orbit. The orbit constrains the eccentricity to 0.97608 ± 0.00004 and the orbital period to 889.8195 ± 0.0003 d. The masses of the two components are 0.87 ± 0.05 M� ... . .. . .. . .. . ..
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