The Effect of Helium Burning Shell Temperature on Models of R Coronae Borealis stars in MESA

The R Coronae Borealis (RCB) stars are believed to be formed primarily through a white dwarf (WD) merger. Simulations of this merger scenario have shown that there are a range of resultant helium burning shell temperatures. In this work, we present our models, created within the Modules for Experiments in Stellar Astrophysics (MESA) framework, that explore the effects of different post-merger helium burning shell temperatures on the surface abundances and evolution of RCB stars. We find a strong dependence on temperature for the surface abundances of elements involved in the CNO cycle, as well as differences in effective temperature and radius of RCBs. We also find that convective mixing of the burning material occurs only in the beginning years of post-merger evolution, with the surface abundances constant during and after the RCB phase, thus providing evidence for why these stars show a strong enhancement of partial helium burning products.