The $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne Breakout Reaction and Impact on X-Ray Bursts

TL;DR

This paper reports the first experimental measurement of the $^{15}$O($ alpha$,$ gamma$)$^{19}$Ne reaction rate, crucial for understanding X-ray burst behaviors, by measuring decay ratios and analyzing their impact on burst patterns.

Contribution

First experimental determination of the $^{15}$O($ alpha$,$ gamma$)$^{19}$Ne reaction rate using decay ratios and lifetime data, informing models of X-ray burst phenomena.

Findings

Measured alpha-decay branching ratios of $^{19}$Ne states.

Derived the first experimental rate of $^{15}$O($ alpha$,$ gamma$)$^{19}$Ne.

Analyzed impact on X-ray burst periodicity.

Abstract

The breakout reaction $^{15}$O($\alpha,\gamma$)$^{19}$Ne, which regulates the flow between the hot CNO cycle and the rp-process, is critical for the explanation of the burst amplitude and periodicity of X-ray bursters. We report on the first successful measurement of the critical $\alpha$-decay branching ratios of relevant states in $^{19}$Ne populated via $^{19}$F($^3$He,t)$^{19}$Ne. Based on the experimental results and our previous lifetime measurements of these states, we derive the first experimental rate of $^{15}$O($\alpha,\gamma$)$^{19}$Ne. The impact of our experimental results on the burst pattern and periodicity for a range of accretion rates is analyzed.