Planetary Nebulae and the Pregalactic Helium Abundance

  • Walter J. Maciel
Conference paper
Part of the International Astronomical Union / Union Astronomique Internationale book series (IAUS, volume 131)

Abstract

Recent work has emphasized the determination of the pregalactic helium abundance by mass Yp and the slope ΔY/ΔZ based on the chemical composition of both galactic and extragalactic H II regions (Pagel, 1987; Pagel et al., 1986).

Keywords

Recent Work Late Stage Stellar Evolution Planetary Nebula Kinematical Property 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. Faúndez-Abans, M., Maciel, W. J. 1986, Astron. Astrophys. 158, 228ADSGoogle Scholar
  2. Faúndez-Abans, M., Maciel, W. J. 1987, Astron. Astrophys. (in press)Google Scholar
  3. Maciel, W. J. 1987, Late Stages of Stellar Evolution, eds. S. Kwok, S. R. Pottasch, Reidel, p. 391Google Scholar
  4. Maciel, W. J., Faúndez-Abans, M. 1985, Astron. Astrophys. 149, 365ADSGoogle Scholar
  5. Pagel, B. E. J. 1987, preprintGoogle Scholar
  6. Pagel, B. E. J., Terlevich, R. J., Melnick, J. 1986, PASP 98, 1005ADSCrossRefGoogle Scholar
  7. Peimbert, M. 1983, Primordial Helium, eds. P. A. Shaver, D. Kunth, K. Kjar, ESO, p. 267Google Scholar
  8. Peimbert, M. 1986, PASP 98, 1057ADSCrossRefGoogle Scholar

Copyright information

© International Astronomical Union 1989

Authors and Affiliations

  • Walter J. Maciel
    • 1
  1. 1.Instituto Astronômico e Geofísico da USPSão PauloBrasil

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