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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.

Document Type

Article

Publication Date

3-10-2005

Notes/Citation Information

Published in The Astrophysical Journal Letters, v. 622, no. 1, p. L73-L75.

© 2005. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

The copyright holder has granted permission for posting the article here.

Digital Object Identifier (DOI)

http://dx.doi.org/10.1086/429370

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