The IUE observation of the active binary II Pegasi = HD 224085

Abstract

II Pegasi is a bright single line spectroscopic binary with an orbital period of 6(d).72. Teh visual light curves of the star exhibit asymmetric light variations with the period very close to the orbital one. The shape of these curves changes on a time scale of years. In connection with the interesting properties of II Peg, it was decided to obtain ultraviolet spectra of this star. These spectra were obtained on September 2, 1979, with both the short-wavelength (1175-1950 A) and the long-wavelength (1900-3200 A) spectrographs of the International Ultraviolet Explorer (IUE) satellite. All spectra were obtained in the low dispersion mode (6 A resolution). Attention is given to the ultraviolet spectra, II Peg as a binary star, the radius of the primary component, the conditions in the chromosphere-corona transition region, and predictins regarding the X-ray emission.