A METHOD FOR ESTIMATING PARALLAXES OF VCBS: MODIFICATION TO HIPPARCOS PARALLAX MEASUREMENTS

Abstract

We presented a method useful for estimating parallaxes of visually close binary stars (VCBS). The method depends on atmospheric modeling of the components of the VCBS. We construct model atmospheres by using a grid of Kurucz solar metalicity blanketed models1, which can be applied to calculate the synthetic spectral energy distribution for each component of the binary separately. In addition to study the entire system. However, the entire observational spectral energy distribution of the system was used as a reference for the comparison with the synthetic ones. We choose Hip4809 system to investigate the method, and we also study its physical and geometrical parameters. The new parallax of the system was estimated as π = 40.32 ± 5.00 mas, which disagrees with the Hipparcos parallax measurement (13.94 ± 0.90 mas). Furthermore the model atmosphere parameters of the components of the system were derived as: [Formula: see text], [Formula: see text], log ga = 4.50 ± 0.13, log gb = 4.50 ± 0.13, Ra = 0.94 ± 0.12R⊙, Rb = 0.93 ± 0.12R⊙, Depending on the derived parameters, the masses of the system's components were estimated as 1.03 ± 0.02M⊙ and 1.01 ± 0.02M⊙ for the primary and secondary components respectively, and their spectral types were concluded as G6V for both of them.