What highly ionised elements are found in the spectrum of WR 102c?
Wolf–Rayet star Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of highly ionised helium and nitrogen or carbon. The spectra indicate very high surface enhancement of heavy elements, depletion of hydrogen, and strong stellar winds. Their surface temperatures range from 30,000 K to around 200,000 K, hotter than almost all other stars.
Pickering series The Pickering series consists of three lines of singly ionized helium found, usually in absorption, in the spectra of hot stars like Wolf-Rayet stars. The name comes from Edward Charles Pickering. The lines are produced by transitions of an electron with principal quantum number n=4 state from a higher energy level. The lines have wavelengths: