NEW AND IMPROVED PARAMETERS OF HD-202908=ADS-14839 - A SPECTROSCOPIC-VISUAL TRIPLE SYSTEM

HD 202908=ADS 14839 is a spectroscopic-visual triple system consisting of three solar-type stars. Eighteen years of spectroscopic observatio ns including coverage of the recent periastron of 1987 January plus vi sual and speckle observations, the latter covering roughly the same in terval as the radial velocities, have been used to obtain a simultaneo us three-dimensional orbital solution. The short-period pair, Aa and A b, has an orbital period of 3.9660465 days and a small but real eccent ricity of 0.0033. The visual pair, A and B, has an orbital period of 7 8.5 yr and an eccentricity of 0.865. The solution yields masses for al l three stars with uncertainties of about 2%, and the distance to the system with an uncertainty of 1.3%. Spectroscopic luminosity ratios, c ombined with the above distance, yield absolute magnitudes with uncert ainties of about 0.1 mag. Thus the system provides three well-determin ed points on the mass-luminosity relationship. The inclinations of the short- and long-period orbits differ by 29 degrees, making the orbits noncoplanar. Assuming synchronous rotation, the rotational and orbita l axes of the short-period pair are aligned. The chromospheric emissio n, lithium abundance, and projected rotational velocity of component B indicate that the system is quite young, probably about the age of th e Hyades Cluster. A comparison with theoretical evolutionary tracks su pports such a conclusion. (C) 1997 American Astronomical Society.