5.5.6. Conclusions from D/H from quasars
Most agree that D is providing the most accurate
although some have one remaining
objection, that there might also be quasar absorbers which show
high values of D/H
The D/H from our group (Burles & Tytler
together with over 50 years of theoretical work and laboratory measurements
of reaction rates, leads to the following values for cosmological parameters
(unlike most errors quoted in this review, which are the usual
1 values, the following are
quoted with 95% confidence intervals):
If we accept that D/H is the most accurate measure of
then observations of the other elements have two main roles. First, they show
that the BBN framework is approximately correct.
Second, the differences between the observed and predicted primordial
abundances teach us about subsequent astrophysical processes.
Recent measurements of 4He
agree with the predictions.
It appears that some 7Li has been destroyed in halo stars
and 3He is both created and destroyed in stars.
- D/H = 3.4 ± 0.5 x 10-5 (measured in quasar spectra)
- = 5.1 ±
0.5 x 10-10 (from BBN and D/H)
- Yp = 0.246 ± 0.0014 (from BBN and D/H)
- 7Li / H = 3.5+1.1-0.9 x
10-10 (from BBN and D/H)
- 411 photons cm-3 (from the CMB temperature)
- b =
3.6 ± 0.4 x 10-31 gcm-3 (from CMB and
h2 = 0.019 ± 0.0024 (from the critical density
- N < 3.20 (from
BBN, D/H and Yp data).