Vol. 668
7. Stellar structure and evolution

Structure and evolution of ultra-massive white dwarfs in general relativity

by L. G. Althaus, M. Camisassa, S. Torres, et al. 2022, A&A, 668, A58 alt

Ultra-massive white dwarfs (WDs) are a key for our understanding of type Ia supernovae, accretion-induced collapse, among other things. The authors present the first set of constant rest-mass ultra-massive O/Ne WD cooling tracks with masses larger than 1.29Msol, which fully take into account the effects of general relativity on their structural and evolutionary properties. As expected, the effects of general relativity increase with the mass of the WDs. As compared to the Newtonian treatment, the WDs have a smaller radius (e.g., by 25 percent) and a shorter cooling time (e.g., by a factor of two), and the stable mass limit is also lower (e.g., ~ 1.36Msol). The authors show that general relativity should be taken into account to probe the structural and evolutionary properties of those most massive WDs.