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arXiv · 2602.15119

Detection horizon for the neutrino burst from the stellar helium flash

Pablo Martínez-Miravé·Irene Tamborra·Georg Raffelt
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Abstract

Low-mass stars ($M\lesssim 2\,M_\odot$) ignite helium under degenerate conditions, eventually causing a nuclear run-away -- the helium flash. The alpha-capture process on $^{14}$N produces a large amount of $^{18}$F, whose subsequent decay spawns an intense $\nu_e$ burst (with average energy of $0.38$ MeV) lasting about a day. We show that, in addition, a strong $1.7$ MeV neutrino line is generated by electron capture on $^{18}$F. Detection is hindered by large backgrounds in state-of-the-art neutrino observatories, such as JUNO. In next-generation facilities, such as the Jinping neutrino experiment, the horizon for a detection with a local significance of $3 \sigma$ would be extended to almost $3$ pc. Although helium flashes occur a few times per year in our Galaxy, there are no stellar candidates approaching the tip of the red giant branch within $10$ pc. Hence, to date, asteroseismology remains the most promising tool for probing the most energetic thermonuclear event in the life of a low-mass star.

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Pablo Martínez-Miravé, Irene Tamborra, Georg Raffelt. 2026-02-16. Detection horizon for the neutrino burst from the stellar helium flash. https://doi.org/10.1103/jw7v-vtms

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