The chromospherically active binary star EI Eridani
نویسنده
چکیده
We present a detailed determination of the astrophysical parameters of the chromospherically active binary star EI Eridani. Our new radial velocities allow to improve the set of orbital elements and reveal long-term variations of the barycentric velocity. A possible third-body orbit with a period of ≈ 19 years is presented. Absolute parameters are determined in combination with the Hipparcos parallax. EI Eri’s inclination angle of the rotational axis is confined to 56. 0 ± 4. 5, its luminosity class IV is confirmed by its radius of 2.37 ± 0.12R⊙. A comparison to theoretical stellar evolutionary tracks suggests a mass of 1.09 ± 0.05M⊙ and an age of ≈ 6.15 Gyr. The present investigation is the basis of our long-term Doppler imaging study of its stellar surface.
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