Abstract
We report on studies of classical nova (CN) explosions where we follow the evolution of thermonuclear runaways (TNRs) on oxygen–neon (ONe) white dwarfs (WDs). Using NOVA, a 1D hydrodynamic computer code, we accrete solar matter until the TNR is ongoing and then switch to a mixed composition. This approach is guided by the results of multidimensional studies of TNRs in WDs, which find that sufficient mixing with WD core material occurs after the TNR is well underway, and levels of enrichment of the CNONeMg elements are reached that agree with observations of CN ejecta abundances. Because the amount of accreted material is inversely proportional to the oxygen abundance, by first accreting solar matter, the amount of accreted material is larger than in those simulations with an initially enriched composition. We vary the mass of the WD (from 0.6 M⊙ to 1.35 M⊙) and the composition of the mixed materials. Our results show large enrichments of 7Be in the ejected gases, implying that ONe CNe and CO CNe may be responsible for a significant fraction (∼100 M⊙) of the Galactic 7Li (∼1000 M⊙). The production of 22Na and 26Al in CN explosions and the γ-ray emission predicted by our simulations are discussed. The WDs in all our simulations eject less material than they accrete and we predict that the WD is growing in mass as a consequence of the CN outburst. ONe CNe, therefore, may be an important channel for accretion-induced collapse events.
| Original language | English |
|---|---|
| Article number | 191 |
| Journal | Astrophysical Journal |
| Volume | 962 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 1 2024 |
Funding
We thank the anonymous referee for the comments, which greatly improved the plots and discussion in this manuscript. We acknowledge useful discussion and encouragement from D. Banerjee, A. Evans, R. Gehrz, K. Hensley, M. Darnley, E. Aydi, J. José M. Hernanz, S. Kafka, L. Izzo, P. Molaro, I. Perron, M. della Valle, A. Shafter, L. Takeda, and the attendees at EWASS18, COSPAR 2018, and HEAD 2019 for their comments. We especially thank P. Molaro for his comments on an earlier draft of this paper, which have been incorporated into the manuscript. This work was supported in part by the U.S. DOE under Contract No. DE-FG02-97ER41041. S.S. and M.B. acknowledge partial support from a NASA Emerging Worlds grant to ASU (80NSSC22K0361) as well as support to S.S. from his ASU Regents’ Professorship. W.R.H. is supported by the U.S. Department of Energy, Office of Nuclear Physics, and C.E.W. acknowledges support from NASA grant 80NSSC19K0868.