Network structure of thermonuclear reactions in nuclear landscape

Nucleosynthesis is a complex process in astro-nuclear evolution. In this work, we constructed a directed, multi-layer, nuclear reaction network, using the substrate-product method from a thermonuclear reaction database, JINA REACLIB. The network contained four layers, namely n-, p-, h- and r-, which correspond to the types of reactions involved in neutrons, protons, He-4 and the remaining atomic particles, respectively. The degree values (i.e. numbers of reactions), for three layers of n-, p-, and h-, have a significant correlation with one another, and their topological structures exhibit a similar regularity. However, the r-layer has a more complex topological structure compared to the other layers; thus, its correlation of degree values with the other three layers is not as strong as that seen in the other layers. To analyze the motif structure of the nuclear reaction network, we used the software package mfinder. We identified the most frequent reaction patterns of the interconnections that occurred amongst the different nuclides. This work provides a novel approach to investigating the nuclear reaction network that prevails in the astrophysical context.