Spectrum Analysis of the Binary Star 53 Aur with a CP3 Component

Abstract

The CP-star 53 Aur (HD 47152, HR 2425) has been assigned in the literature different types of peculiarity. Bertaud (1959) classified it as A0p-EuCr, Cowley et al. (1969) as B9p-Eu(Cr?), Osawa (1965) as Hg and Zverko (1974) as Mn -type. MacAlister (1978) discovered its binary nature and Tokovinin (1986) first determined its orbit with a period of 13.7 y. Subsequent interferometric observations by Baize (1989) yielded new orbital elements with a period of 25.816 y, total mass of 5.8 M⊙ and magnitude difference of two B9 components 0.3 mag. Adelman (1982) performed spectrophotometry and fitted the Balmer jump with Teff=10 500 K, while the Paschen continuum with Teff=9 500 K, log g=4 in both cases. Palmer (1965) estimated the projected rotational velocity to 325 km s−1 from the width of the Ca II-K line, while Wolff and Preston (1975) obtained 33 km s−1 from the Mg II 448.1 nm line. In this work we analyze high-dispersion spectra obtained in two distant orbital phases, namely in 1975 and in 1992 to distinguish the components of the system.