Theoretical He I emissivities in the case B approximation

R. L. Porter, R. P. Bauman, G. J. Ferland, K. B. Macadam

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


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.

Original languageEnglish
Pages (from-to)L73-L75
JournalAstrophysical Journal
Issue number1 II
StatePublished - Mar 20 2005


  • Atomic data
  • Atomic processes
  • ISM: Atoms -
  • ISM: clouds
  • Plasmas

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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