The impact of axion-like particles on late stellar evolution. From intermediate-mass stars to core-collapse supernova progenitors

Abstract

Context. Stars with masses ranging from 3 to 11 M exhibit multiple evolutionary paths. Less massive stars in this range conclude their evolution as carbon-oxygen (CO) white dwarfs (COWDs). However, stars that achieve carbon ignition before the pressure induced by the degenerate electron halts the core contraction would either form massive CONe or ONe WDs, or they might undergo an electron-capture supernova (ECSN). Alternatively, they could photo-disintegrate neon and proceed with further thermonuclear burning, ultimately leading to the formation of a gravitationally unstable iron core. Aims. An evaluation of the impact of the energy loss caused by the production of axion-like-particles (ALPs) on the evolution and final destiny of these stars is the main objective. Methods. We computed various sets of stellar models, all with solar initial composition, varying the strengths of the ALP coupling with photons and electrons. Results. As a consequence of an ALP thermal production, the critical masses for off-center C and Ne ignitions are both shifted upward. When the current bounds for the ALP coupling strengths are assumed, the maximum mass for CO WD progenitors is about 1.1 M heavier than that obtained without the ALP energy loss, while the minimum mass for a core collapse supernova (CCSN) progenitor is 0.7 M higher. Conclusions. Current constraints from observed type II-P supernova light curves and pre-explosive luminosity do not exclude an ALP production within the current bounds. However, the maximum age of CCSN progenitors, as deduced from the star formation rate of the parent stellar population, would require a lower minimum mass. This discrepancy can be explained by assuming a moderate extra mixing (as due to core overshooting or rotational induced mixing) above the fully convective core that develops during the main sequence.