Determining Primordial Abundances
- Created during BBN, but also created inside stars
expelled during late stages of stellar evolution. Helium abundance
should rise with metallicity.
- Measure using Helium abundances in HII regions in
low metallicity dwarf galaxies.
- Created during BBN, essentially nowhere else. Destroyed inside
stars. Deuterium measurements should be lower limits on primordial
- Measure using quasar absorption line spectra.
Image courtesy Neil Crighton, Swinburne U
- 7Li created during BBN, inside stars, and
during cosmic ray collisions ("spallation").
- 6Li only created during cosmic ray
- Measure lithium in halo dwarf stars with T>6000K so that lithium in atmosphere is not burned during convective cycling.