Lecture 18

Primordial Nucleosynthesis Observations: Light Elements Measured

• Lithium-7: extreme Population II stars
  • extreme Pop II (halo) stars
    compare Li strength vs Ca
  • comparison: solar spectrum
  • example data: spectra from Ryan et al 1998; Bonifacio et al; Li vs Fe
• Helium-3: Galactic H II regions
  • a recent compilation: Bania et al 2002
  • also see Vangioni-Flam et al 2003

BBN: Theory vs Observations

• Predictions: Schramm plot (Cyburt, Fields, & Olive 2003,2008)
• Concordance

BBN: Implications

• baryon density
• dark matter: two kinds!
  • baryonic dark matter: e.g., hot gas in collapsed structures and intergalactic gas; MACHOs (well, probably not MACHOs)
  • non-baryonic dark matter

BBN in Light of the CMB

• Overview: BBN+CMB Schramm plot
• Standard BBN: Light element CMB predictions vs observations (CFO 2003)