Nucleosynthesis and Tracer Methods in Type Ia Supernovae

Abstract

Type Ia supernovae (SNe Ia) are explosions of white dwarf stars in interacting binary systems, powered by thermonuclear fusion of lighter elements such as He, C, and O to heavier, more tightly bound elements such as Si, Ca, Fe, or Ni. The binary interaction, either accretion or merger, triggers a supernova explosion that disperses the synthesized heavy elements into the surrounding space. These metals can then be observed in the interstellar medium or in the atmospheres of future generation of stars. Together with core-collapse supernovae, asymptotic giant branch stars, binary neutron star mergers (kilonovae), and classical novae, SNe Ia rank among the main production sites of a large number of nuclides. SNe Ia are the main sources of the so-called iron-peak elements, from Ti (Z = 22) to Zn (Z = 30), and also contribute significantly to the universal abundance of the so-called intermediate mass elements, in particular the even atomic number elements Si, S, Ar, and Ca. Observational evidence in recent years has consolidated that SNe Ia do not constitute a homogeneous class of objects and that a number of different subclasses correspond to different evolutionary pathways. As a result, a number of viable explosion mechanisms and associated progenitor systems exist in the literature. This chapter reviews the technical aspects of how nucleosynthetic yields are calculated for such numerical multidimensional explosion models via the tracer particle method. It summarizes key differences in the nucleosynthetic signatures of the different SN Ia explosion models and discuss ways in which these distinct signatures can be used to untangle the SN Ia progenitor and explosion type problem, from direct detection of nuclear gamma-ray lines to the distribution of chemical elements in supernova remnants and the imprints on the chemical enrichment history of galaxies over cosmic time.