A study of UV spectra of zeta Aur/VV CEP stars. IX. Mass-loss and wind properties of the solar type supergiant 22 VUL (G3Ib-II).

Abstract

Phase-covering, high resolution IUE spectra of wind lines of the Zeta Aurigae type eclipsing binary 22 Vul (G3 Ib-Il + B9) have been analysed in terms of mass4oss and wind properties. We find a wind velocity of v∞ = 160 ± 20KM s^-1 and a mass-loss rate of M = 6 1O^-9 M_sun yr^-1 for the G supergiant primary. The observed population of excited Fe II levels is much higher in the wind of 22 Vul than in the wind of 32 Cyg. Since radiative excitation via higher levels cannot be excluded, the estimate of the wind electron temperature of 30 ± 10 1O^-4 K made with the assumption of pure electron collisions remains to be confirmed by improved methods.