Measurement of ${}^{19}$F($p$,$\gamma$)${}^{20}$Ne reaction suggests CNO break-out in first stars

Abstract

The origin of calcium production in the first stars (Pop III stars), which formed out of the primordial matter of the Big Bang, and their fates, remain most fascinating mysteries in astrophysics. Advanced nuclear burning and supernovae were thought to be the dominant source of the Ca production seen in all stars. Here we report on a qualitatively different path to Ca production through break-out from the "warm" carbon-nitrogen-oxygen (CNO) cycle. We extend direct measurement of the ${}^{19}$F($p$, $\gamma$)${}^{20}$Ne break-out reaction down to an unprecedentedly low energy point of 186 keV and discover a key resonance at 225 keV. In the domain of astrophysical interest, at around 0.1 giga kelvin, this thermonuclear ${}^{19}$F($p$,$\gamma$)${}^{20}$Ne rate is up to a factor of 7.4 larger than the previous recommended rate. Our stellar models show a stronger break-out during stellar hydrogen burning than thought before, and may reveal the nature of Ca production in Pop III stars imprinted on the oldest known ultra-iron poor star, SMSS0313-6708. This result from the China Jinping Underground Laboratory, the deepest laboratory in the world, offering an environment with extremely low cosmic-ray induced background, has far-reaching implications on our understanding of how the first stars evolve and die. Our rate showcases the impact that faint Pop III star supernovae can have on the nucleosynthesis observed in the oldest known stars and first galaxies, key mission targets of the James Webb Space Telescope.

32 pages, 8 figures, 6 tables

References in corpus (4)

• LUNA: Nuclear Astrophysics Deep Underground
• Black hole formation and fallback during the supernova explosion of a $40{\mathrm{M}}_{\odot }$ star
• Pop III $\text{i}$-process Nucleosynthesis and the Elemental Abundances of SMSS J0313-6708 and the Most Iron-Poor Stars
• Stellar Yields of Rotating First Stars. I. Yields of Weak Supernovae and Abundances of Carbon-enhanced Hyper Metal Poor Stars

Cited by in corpus (1)

• Underground laboratory JUNA shedding light on stellar nucleosynthesis