Atmosphere of the K-Type Supergiant Component of 32 Cygni

Abstract

Spectroscopic observations of 32 Cyg were carried out around the Ca II H and K lines at the Okayama Astrophysical Observatory during the ingress of two eclipses in 1984 and 1987 by using the 1.88-m reflector equipped with a diode array detector. It was found that the main opacity source of the K-type supergiant component is line absorption due to neutral metals in the upper atmosphere and continuum absorption due to negative hydrogen ions in the lower atmosphere. The transition occurred across a zone thinner than 1 % of the K star’s radius in radial thickness.