25. Nuclear reactions and element synthesis in stellar atmospheres

Abstract

A modified discussion of surface nuclear reactions in magnetic stars is given. The anomalous abundance effects found in magnetic stars are briefly described. It is suggested that the processes of particle acceleration are similar to those taking place in the solar atmosphere which give rise to the cosmic ray bursts observed by Wild, Roberts, and Murray, and to the solar component of cosmic radiation. Calculations of the rate of loss of energy following particle acceleration suggests that the duration of the hot spot is 1 ≲ sec. It is estimated that in the region of acceleration (p, n) reactions will enable a ratio nn/np ⋍ 10–2–10–3 to be built up. The majority of these neutrons will diffuse from the excited regions and form deuterium in the quiescent atmosphere. This deuterium will be continuously built up and re-acceleration will lead to the release of neutrons, some of which will be captured by the Fe group, eventually giving rise to the observed anomalous abundances of the heavy elements. Also the reaction H(d, γ) He3 may give rise to the formation of some He3.