Recent deuterium observations and big bang nucleosynthesis constraints

Lawrence M. Krauss, Peter J. Kernan

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18 Scopus citations


A new observation of D in a primordial gas cloud, made using the high-resolution spectrograph at the Keck telescope, indicates an abundance D/H = (1.9-2.5) × 10-4 (Songaila et al. 1994). Because the new measurement is substantially larger than previous, Galactic estimates, this would force a reassessment of big bang nucleosynthesis (BBN) methodology and predictions - if it is confirmed. Using a new BBN Monte Carlo code and analysis technique (Kernan & Krauss 1994), we derive constraints implied by a lower limit of D/H = 1.9 × 10-4. We find ΩB ≤ 0.0068 h-2, which is definitively incompatible with baryonic halo dark matter. We also explore implications of combining the D measurement with other light-element abundances. 7Li provides a lower bound, ΩB ≥ 0.004 h-2. Also, the initial 4He mass fraction (Yp) would have to be less than 23.5%, assuming three light neutrino species - in good agreement with present observational estimates. Finally, observational upper limits of Yp ≤ 24% and 7Li/H ≤ 2.3 × 10-10 would now allow the number of effective neutrino species to be as large as 3.9.

Original languageEnglish (US)
Pages (from-to)L79-L81
JournalAstrophysical Journal
Issue number2 PART 2
StatePublished - Sep 10 1994


  • Cosmology: observations
  • Early universe
  • Nuclear reactions, nucleosynthesis, abundances

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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