Generating Process Explanations in Nuclear Astrophysics Generating Explanations in Astrophysics

In this paper we describe ASTRA, a computational aid for generating process explanations in nuclear astrophysics. The system operates in two stages, the rst using knowledge of quantum theory to produce a set of legal reactions among elements and the second searching for pathways of such reactions that explain the evolution of some element in terms of lighter ones. ASTRA has found apparently novel reactions that involve proton and neutron capture, as well as novel fusion reactions that produce neutrons and deuterium. The system has also generated reaction pathways for helium, carbon, and oxygen that do not appear in the scientiic literature. Discussions with an expert in the domain suggest these results have scientiic merit. However, ASTRA also nds many other reaction pathways that are less interesting and that point toward directions for future research.