The Line Variability of 78 Vir (A2p SrCrEu) in the Far-ultraviolet

Line variations are studied in the far-ultraviolet spectra of 78 Vir collected with International Ultraviolet Explorer at phases of far-UV maximum and at phases of far-UV minimum. The far-UV spectrum of 78 Vir is populated with low-excitation transitions of light elements and iron-peak elements. The low excitation C I and N I lines are stronger at phases of far-UV minimum. Carbon appears to be underabundant and aluminum very underabundant in the atmosphere of 78 Vir. The lines of Si I and Si II are stronger at phases of far-UV minimum. Many lines which strengthen at phases of far-UV minimum are due to low-excitation lines of Fe II and Cr II which suggests that both iron and chromium are unevenly distributed over the surface of 78 Vir.