1208.4210 (Motohiko Kusakabe et al.)

Production of 9Be through alpha-fusion reaction of metal-poor cosmic ray and stellar flare    [PDF]

Motohiko Kusakabe, Masahiro Kawasaki

Spectroscopic observations of metal-poor stars have indicated possible 6Li abundances which are much larger than the primordial abundance predicted in standard big bang nucleosynthesis model. Possible mechanisms of 6Li production in metal-poor stars include pregalactic and cosmological cosmic ray (CR) nucleosynthesis and nucleosynthesis by flare accelerated nuclides. We study the 9Be production by two-step alpha-fusion reactions of CR or flare accelerated 3,4He through 6He and 6,7Li, in pregalactic structure, intergalactic medium and stellar surfaces. We solve transfer equations of CR or flare particles and calculate nuclear yields of 6He, 6,7Li and 9Be taking account of probabilities of processing 6He and 6,7Li into 9Be via fusions with alpha particles. Yield ratios, i.e., 9Be/6Li, are then calculated for the CR and flare nucleosynthesis models. We suggest that the future observations of 9Be in metal-poor stars may find enhanced abundances originating from metal-poor CR or flare activities.

View original: http://arxiv.org/abs/1208.4210