Theoretical He I line intensities in gaseous nebulae: NGC 1976, 6572 and IC 4997

J. B. Kingdon, G. J. Ferland

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Smits has recently calculated theoretical He I intensities for a large number of lines for conditions appropriate to gaseous nebulae. These are likely to remain the definitive calculations for some time to come. A comparison of these line ratios with observed values in three nebulae reveals some discrepancies. We show that these discrepancies are reduced when collisional effects from the metastable 23S level are included, and that it is not necessary to invoke an unknown depopulation mechanism for the He I 23S level.

Original languageEnglish
Pages (from-to)723-725
Number of pages3
JournalMonthly Notices of the Royal Astronomical Society
Volume282
Issue number3
DOIs
StatePublished - 1996

Keywords

  • ISM: abundances
  • Planetary nebulae: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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