Fe in White Dwarfs

Neutron rich nuclei with a small neutron excess, such as ²²Ne and ⁵⁶Fe, may separate in crystallizing WDs and sediment to the core. These separation processes release gravitational potential energy and heat the WD, affecting inferred ages. With a detailed understanding of separation and sedimentation in WDs, we may be able to predict the abundance of neutron rich nuclei in their cores, with implications for the ¹⁴N(α,γ)¹⁸F and ¹⁸O(α,γ)²²Ne reactions that are responsible for converting CNO nuclei into ²²Ne. Recent work on fractionalization processes in WDs finds that ⁵⁶Fe may strongly separate into a nearly pure inner core, which may impact type 1a supernova explosions. This talk will present a brief overview of these problems, the current state of the field, and discuss implications for nuclear astrophysics.