Low energy particle production of short-lived nuclides in the early solar system

Abstract

Model calculations for the production of the short-lived nuclides ¹⁰Be, ²⁶Al, ⁴¹Ca and ⁵³Mn by solar energetic particles (SEP) in the asteroidal region during the early evolution of the solar system are presented. Based on the results of these calculations and the initial solar system abundances of the short-lived nuclides inferred from meteorite data, particularly for ¹⁰Be that is a product of energetic particle interactions, we can infer the effective SEP irradiation dose received by the solar nebula material. The presence of ¹⁰Be in early solar system objects, that are devoid of ²⁶Al and ⁴¹Ca at detectable levels rules out SEP irradiation as a common source of all the short-lived nuclides present in the early solar system and also allows us to characterize the energy spectrum of the SEP responsible for production of ¹⁰Be. The results obtained in our study, suggest that the contribution towards the inventory of the short-lived nuclides in the early solar system from SEP irradiation is negligible for ²⁶Al, while it may account for ~10-20% of ⁴¹Ca and ⁵³Mn. Injection of freshly synthesized stellar material remains the most viable source of most of the short-lived nuclides (other than ¹⁰Be) present in the early solar system.