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Space Science Reviews

, Volume 84, Issue 1–2, pp 95–103 | Cite as

Temperature Fluctuations, H II Region Abundances, and Primordial Helium

  • Gary Steigman
  • Sueli M. Viegas
  • Ruth Gruenwald
Article
  • 24 Downloads

Abstract

There is evidence for temperature fluctuations in Planetary Nebulae and in some Galactic H II regions. If such fluctuations occur in the low metallicity, extragalactic H II regions used to probe the primordial helium abundance, the derived 4He mass fraction, YP, could be systematically different from the true primordial value. Although this effect could be large, there are no data which allow us to estimate the size of the temperature fluctuations for the extragalactic H II regions. Therefore, we have explored this effect via Monte Carlo simulations of the data in which the abundances derived from a fiducial data set are modified by ΔT chosen from a distribution with 0 ≤ ΔT ≤ ΔTmax where ΔTmax is varied from 500 K to 4000 K.

Temperature Fluctuations H II Region Abundances Primordial Helium 

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Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Gary Steigman
    • 1
  • Sueli M. Viegas
    • 2
  • Ruth Gruenwald
    • 2
  1. 1.Departments of Physics and AstronomyThe Ohio State UniversityColumbusUSA
  2. 2.Instituto Astronômico e GeofísicoUniversidade de São PauloSão PauloBRASIL

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