Observations of Of-star wind variability.
Grady, C. A.; Snow, T. P., Jr.; Timothy, J. G.
United States
Abstract
Nightly variations in He II λ4686 have been observed in four Of stars, HD 152408, HD 151804, 9 Sge, and λ Cep. Three of the stars were not previously known to show such variations. In one case, λ Cep, simultaneous observations with IUE showed variations in ultraviolet resonance-line profiles during the same time period as those in He II λ4686. This implies that the perturbations causing the He II λ4686 variability affect the entire wind acceleration zone.