Somaya Saad¹ and Mohamed Nouh^2
1National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt
²Faculty of Science, Northern Border University, Arar, Saudi Arabia

Abstract. Using new spectroscopic data, we re-investigate the B-type eclipsing binary u Her. The method of spectrum disentangling is used to decompose the spectrum of the system to its individual spectra. Comparison of the decomposed spectra with the theoretical spectra is done to obtain the main fundamental parameters for both components. We analyzed a total of 50 new electronic spectra obtained through 1994-2004 of the spectroscopic binary star u Her. The radial velocity variations of the binary components are analyzed. The orbital solution suggests a circular orbit with a period of 2.^d051 and semi amplitude of 101±1 km s^-1. Comparison against the synthetic grid gives T_eff=19000±1000K, log g=3.5±0.25 with v sin i=145±5 km s^-1 for the primary and T_eff=11000±250K, log g=3.5±0.25 with v sin i=105±5 km s^-1 for the secondary.

Keywords: stars: variables -- binaries: eclipsing -- stars: individual: u Her

Download Full Paper