Evolution of Lithium-Beryllium-Boron and Oxygen in the early Galaxy

Oxygen is a much better evolutionary index than iron to describe the history of Lithium-Beryllium-Boron (LiBeB) since it is the main producer of these light elements at least in the early Galaxy. The O-Fe relation is crucial to the determination of the exact physical process responsible for the LiBeB production. At low metallicity, if [O/Fe] vs [Fe/H] is flat, then the production mode is independent of the interstellar metallicity, BeB is proportional to oxygen, i.e. is of primary nature. If not, the production mode is function of the progressive enrichment in O of the interstellar medium, BeB varies rather as the square of O, i.e. is of secondary nature. In the first case, fast nuclei enriched into He, C and O injected by supernovae and accelerated in surrounding superbubbles would explain the primary trend. In the second case, the main spallative agent would be the standard galactic cosmic rays. Calculated nucleosynthetic yields of massive stars, estimates of the energy cost of production of beryllium nuclei, and above all recent observations reported in this meeting seem to favor the primary mechanism, at least in the early Galaxy.Comment: invited review, IAU Symposium, JD8, Manchester, August 2000, New Astronomy Review, in press 6 pages 1 figur

Lithium-Beryllium-Boron and Oxygen in the early Galaxy

Oxygen is a much better evolutionary index than iron to follow the history of Lithium-Beryllium-Boron (LiBeB) since it is the main producer of these light elements at least in the early Galaxy. The O-Fe relation is crucial to the determination of the exact physical process responsible for the LiBeB production. Calculated nucleosynthetic yields of massive stars, estimates of the energy cost of Be production, and above all recent observations reported in this meeting seem to favor a mechanism in which fast nuclei enriched into He, C and O arising from supernovae are accelerated in superbubbles and fragment on H and He in the interstellar medium.Comment: Invited Review, IAU, JD8, Manchester, August 2000, to be published in Highlights of Astronom

Nuclear Gamma ray Astronomy in the perspective of the INTEGRAL satellite

We present a broad overview of the principal processes and astrophysical sites of gamma-ray line production and review the main pre-INTEGRAL satellite observations to set the stage to the next European era of gamma-ray line astronomy.Comment: 5 pages, 0 figures, in "International Nuclear Physics Conference, Paris, August 1998, to be published Elsevier Ed

The Impact of the NACRE Compilation on the Big Bang Nucleosynthesis

We update the Big Bang Nucleosynthesis (BBN) calculations on the basis of the recent NACRE compilation of reaction rates. We estimate the uncertainties related to the nuclear reaction rates on the abundances of D, 3He, 4He, 6Li, 7Li, 9Be, 10B and 11B of cosmological and astrophysical interest. We use lithium as the main indicator of the baryon density of the Universe, rather than deuterium.Comment: 3 pages, 1 figure, contribution to Nuclei in the Cosmos 2000, proceedings to appear in Nucl. Phy

Standard big bang nucleosynthesis and primordial CNO Abundances after Planck

Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model. The recent results by the Planck satellite mission have slightly changed the estimate of the baryonic density compared to the previous WMAP analysis. This article updates the BBN predictions for the light elements using the cosmological parameters determined by Planck, as well as an improvement of the nuclear network and new spectroscopic observations. There is a slight lowering of the primordial Li/H abundance, however, this lithium value still remains typically 3 times larger than its observed spectroscopic abundance in halo stars of the Galaxy. According to the importance of this "lithium problem", we trace the small changes in its BBN calculated abundance following updates of the baryonic density, neutron lifetime and networks. In addition, for the first time, we provide confidence limits for the production of 6Li, 9Be, 11B and CNO, resulting from our extensive Monte Carlo calculation with our extended network. A specific focus is cast on CNO primordial production. Considering uncertainties on the nuclear rates around the CNO formation, we obtain CNO/H \approx (5-30) x 10^{-15}. We further improve this estimate by analyzing correlations between yields and reaction rates and identified new influential reaction rates. These uncertain rates, if simultaneously varied could lead to a significant increase of CNO production: CNO/H \sim 10^{-13}. This result is important for the study of population III star formation during the dark ages.Comment: Version to match accepted version in JCAP. Results unchange