Spallative Nucleosynthesis in Supernova Remnants. I. Analytical Estimates

TL;DR

This paper provides analytical estimates of beryllium production via spallative nucleosynthesis in supernova remnants, highlighting the importance of shock acceleration and early Galactic conditions in understanding Be abundance.

Contribution

It introduces analytical calculations of Be yields from supernova remnants considering shock acceleration and early Galactic evolution, emphasizing dynamical effects.

Findings

Be production in early Galaxy is poorly understood

Shock acceleration favors CNO nuclei

Reconsideration of observational data may be needed

Abstract

Spallative nucleosynthesis is thought to be the only process capable of producing significant amount of Beryllium (Be) in the universe. Therefore, both energetic particles (EPs) and nuclei to be spalled (most efficiently C, N and O nuclei in this case) are required, which indicates that supernovae (SNe) may be directly involved in the synthesis of the Be nuclei observed in the halo stars of the Galaxy. We apply current knowledge relating to supernova remnant (SNR) evolution and particle shock acceleration to calculate the total Be yield associated with a SN explosion in the interstellar medium, focusing on the first stages of Galactic chemical evolution (i.e. when metallicity Z < 0.01 Z_odot) We show that dynamical aspects must be taken into account carefully, and present analytical calculations of the spallation reactions induced by the EPs accelerated at both the forward and the reverse shocks following the SN explosion. Our results show that the production of Be in the early Galaxy is still poorly understood, and probably implies either selective acceleration processes (greatly favouring CNO acceleration), reconsideration of the observational data (notably the O vs. Fe correlation), or even new energy sources.