Rediscussion of eclipsing binarties. XV. Alpha Coronae Borealis, a main-sequence system with components of types A and G.

The presented analysis of α CrB is based on the Ebbighausen (1976) spectroscopic observations of the primary component, on the McDonald Reticon observations of the secondary, and on the Kron-Gordon (1953) photometric observations at 0.72 μm. The primary component, with mass 2.6 M_sun; and spectral type A0, lies about 0.4 mag above the zero-age main sequence, while the secondary, with mass 0.92 M_sun;, has a radiative flux corresponding to a type near G5, and must lie close to the ZAMS. The system is unique among analyzed main-sequence systems with respect to its small mass ratio and large magnitude difference between the components.