Theoretical He I Emissivities in the Case B Approximation
/ Authors
/ Abstract
We calculate the He I case B recombination cascade spectrum using improved radiative and collisional data. We present new emissivities over a range of electron temperatures and densities. The differences between our results and the current standard are large enough to have a significant effect not only on the interpretation of observed spectra of a wide variety of objects, but also on determinations of the primordial helium abundance.
Journal: The Astrophysical Journal Letters
DOI: 10.1086/429370