Shell spectrum of CH Cyg at the brightening of the star at the end of 1981

Abstract

When CH Cyg brightned at the end of 1981, it had a well-developed shell spectrum. The shell of the star has been investigated on the basis of two spectrograms with reciprocal dispersion 4.2 A/mm. It is shown that the shell lines are formed around the hot component of CH Cyg. An ionization temperature of 10,000 K, an electron density of 10 to the 12th/cu cm, and a dilution coefficient of W 0.1 - 0.001 were determined by the curve-of-growth method. It is concluded that the physical conditions in the accreting shell are close to the conditions in the atmospheres of very bright supergiants. 20 references.