The Temperature of the Supergiant gamma Per

Abstract

Because the bright supergiant α Per is located in cluster, and because its angular diameter has been measured, its log g is known observationally, as is its atmospheric microturbulence. Using these observed parameters, we compare its energy distribution derived from lUE spectra and B, V, R, I, J, and K with model atmospheres convolved with instrumental sensitivity functions. The two most important advances in this study as compared with previous work are the use of well-calibrated ultraviolet fluxes and the use of models with an appropriate microturbulence. Because the ultraviolet flux is sensitive to log g and microturbulence, as well as temperature, we fix log g at 1.5 and microturbulence at 4 km s^-1, and derive the temperature from the best fit to the energy distribution (6270 K). Other recent temperature determinations are discussed, as are the sources of error.