Theoretical He I Emissivities in the Case B Approximation

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.

Accepted to ApJL

References in corpus (2)

• Improving Predictions for Helium Emission Lines
• Temperature Bias and the Primordial Helium Abundance Determination

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