The triple system HD 165590: a spectroscopic and photometric study

© European Southern Observatory. © The American Astronomical Society. The INT 2.5 m on the island of La Palma and the 1.23 m and 2.2 m telescopes at Calar Alto Observatory are operated, respectively, by the Royal Greenwich Observatory at the Spanish Roque de los Muchachos Observatory (Instituto de Astrofísica de Canarias), and the Max Plank Institut for Astronomie at the Centro Astronómico Hispano-Alemán of Calar Alto (Almería, Spain). We want to express our gratitude to the staff of both Observatorties for their help during the observational campaigns. This work has been supported by the Spanish Comisión Interministerial de Ciencia y Tecnología under grants PB86-0536-C02 and PB87-0235.
A detailed study of the system V772 Her = HD 165590 = ADS 11060 AB is presented. The three identified components are found to be late type stars close to the zero-age main sequence with high rotational velocities. Spectroscopic observations allowed a quantitative determination of stellar activity indicators for the two members of the close binary as well as for the visual companion. An estimation of the most relevant physical parameters has been derived from the colour indices of each of the components and the close system has been found to be an eclipsing binary. This additional source of information combined with published measures of radial velocities, provides the absolute dimensions of the component stars (1.1 and 0.6 solar masses, and 0.9 and 0.6 solar radii) which confirm that the system is very little evolved. Moreover, a distance of 32 +/- 4 parsecs has been found to V772 Her in good agreement with available trigonometric determinations. Finally, we have compared these results with evolutionary models for main sequence stars of solar chemical composition.
Comisión Interministerial de Ciencia y Tecnología (CICYT), España
Ministerio de Ciencia e Innovación (MICINN), España
Depto. de Física de la Tierra y Astrofísica
Fac. de Ciencias Físicas
TRUE
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