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Some aspects of the chemical evolution of 4He in the Galaxy: the He/H radial gradient and the ΔY/ΔZ enrichment ratio
Published online by Cambridge University Press: 25 May 2016
Abstract
Two aspects of the chemical evolution of 4He in the Galaxy are considered on the basis of a sample of disk planetary nebulae by the application of corrections due to the contamination of 4He from the progenitor stars. First, the He/H radial gradient is analyzed, and then, the helium to heavy element enrichment ratio is determined for metallicities up to the solar value.
- Type
- 3. Abundances of D, 3He and 4He
- Information
- Symposium - International Astronomical Union , Volume 198: The Light Elements and their Evolution , 2000 , pp. 204 - 213
- Copyright
- Copyright © Astronomical Society of the Pacific 2000