The advanced evolution of massive stars: I. New reaction rates for carbon and oxygen nuclear reactions

Article Article scientifique Article The advanced evolution of massive stars: I. New reaction rates for carbon and oxygen nuclear reactions eng 2025-10-09 2025-10 author Dumont Thibaut 0000-0003-3016-4201 881368 author Bonhomme A. 0000-0002-0218-2835 author Griffiths A. 0000-0001-7594-1284 author Choplin A. 0000-0001-6159-8470 author Aloy M. A. 0000-0002-5552-7681 author Meynet Georges 0000-0001-6181-1323 22422 Département d'astronomie (ASTRO) author Godbey K. 0000-0003-0622-3646 author Simenel C. 0000-0002-2356-7769 author Scamps G. author Castillo F. author Cosoli-Ortega A. author Courtin S. A86 10.1051/0004-6361/202555326 0004-6361 https://www.aanda.org/10.1051/0004-6361/202555326 Context. The nuclear rates for reactions involving 12 C and 16 O are key to computing the energy release and nucleosynthesis evolution of massive stars during their advanced burning phases. Ultimately, these burning rates shape the stellar structure and evolution and influence the nature of the compact objects produced at the end of the stellar life. Aims. We explore the implications of new nuclear reaction rates from both experimental and theoretical studies for 12 C( α , γ ) 16 O, 12 C+ 12 C, 12 C+ 16 O, and 16 O+ 16 O reactions for massive stars. Our goal is to investigate how the chemical structure and nucleosynthesis evolve from the He-exhaustion stage to the O-burning phase and how these processes influence the ultimate stellar fate. Methods. We computed rotating and non-rotating models for stars of different masses at solar metallicity. We used the stellar evolution code GENEC, which includes a large network of nuclear reactions and isotopes involved in advanced phases, as well as updated rates for 12 C( α , γ ) 16 O. For the three fusion reactions involving 12 C and 16 O, we considered new rates following a data-driven fusion suppression scenario (hereafter HIN(RES)) and new theoretical rates obtained with time-dependent Hartree-Fock (TDHF) calculations. Results. The updated 12 C( α , γ ) 16 O rates mainly impact the chemical structure evolution changing the 12 C/ 16 O ratio at He-exhaustion and have little effect on the CO core mass. This variation in the 12 C/ 16 O ratio is in some cases critical for predicting the final fate of the model, which is very sensitive to 12 C abundance, and in particular the 20 M ⊙ remnant may change from a black hole to a neutron star. The He-burning (C-burning) lifetime is also decreased (increased) by about −2% (+15%). The combined new rates for 12 C+ 12 C and 16 O+ 16 O fusion reactions according to the HIN(RES) model lead to shorter C- and O-burning lifetimes by ≈ − 10%, and −50%, respectively, and shift the ignition conditions to higher temperatures and densities. In contrast, the theoretical TDHF rates primarily affect C-burning, increasing its duration by about 30% and lowering the ignition temperature. These changes modify the chemical structure of the core, the size and duration of C-burning shells, and hence their compactness. They also impact the central and shell nucleosynthesis (by ±1 dex and by factors of ±2–10, respectively), while 12 C+ 16 O reaction rates variations remain the least important. Conclusions. The present work shows that accurate reaction rates for key processes in massive star evolution and nucleosynthesis drive significant changes in stellar burning lifetimes, chemical evolution, and stellar fate. The multiple and cumulative consequences of these changes are significant and should not be neglected. In addition, discrepancies between experimental and theoretical rates introduce uncertainties in model predictions, influencing both the internal structure and the composition of the supernova ejecta. Dewey 520 26 Département d'astronomie 12 false Astronomy & astrophysics 702 66b38a81-f4aa-48ec-b6f4-ea7eb5e09eb9 Article (Published version) Public Article_scientifique_from_crossref.pdf 3853632 application/pdf CC BY-4.0 a17d35fcbac01cb0f887a7822d9d8e06e5fa43655fd4ee9f2a8d2e77e376b9bc openAccess Faculté des sciences / Département d'astronomie

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The advanced evolution of massive stars: I. New reaction rates for carbon and oxygen nuclear reactions	Astronomy & astrophysics	2025	2	0
Transport processes in solar-type stars		2021	572	397

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