* Astronomy

Title: Physical Parameters of the Visually Close Binary Systems Hip70973 and Hip72479
Authors: Mashhoor Al-Wardat

Atmospheric modelling of the components of the visually close binary systems Hip70973 and Hip72479 was used to estimate the individual physical parameters of their components. The model atmospheres were constructed using a grid of Kurucz solar metallicity blanketed models, and used to compute a synthetic spectral energy distribution for each component separately, and hence for the combined system. The total observational spectral energy distributions of the systems were used as a reference for the comparison with the synthetic ones. We used the feedback modified parameters and iteration method to get the best fit between synthetic and observational spectral energy distributions. The physical parameters of the components of the system Hip70973 were derived as: Ta eff = 5700±75 K, Tb eff = 5400±75 K, log ga = 4.50±0.05, log gb = 4.50±0.05, Ra = 0.98±0.07 solar radii, Rb = 0.89±0.07 solar radii, and pi = 26.25 ±1.95 mas, with G4 & G9 spectral types. And those of the system Hip72479 as: Ta eff = 5400 ±50 K, Tb eff = 5180 ±50 K, log ga = 4.50 ±0.05, log gb = 4.60 ±0.05, Ra = 0.89 ±0.07 solar radii, Rb = 0.80 ±0.07 solar radii, and pi = 23.59 ±1.00 mas with G9 & K1 spectral types.

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