Identification of He3 in the Binary System 68u Herculis

From a radial velocity study of 60 spectrograms of the binary system 68u Herculis, systematic velocity differences have been found to exist between the He I singlet lines and the He I triplet lines of the primary component. These differences are independent of orbital phase, date of observation of spectrograph employed and can be interpreted in terms of the existence of a large fraction of He³ in the atmosphere of the primary component. $$\text{A}\,\text{He}^{3}/\text{He}^{4}$$ ratio of between 4 : 1 and 49 : 1 is suggested.