Comment on "15O(alpha,gamma)19Ne Breakout Reaction and Impact on X-Ray Bursts"

TL;DR

This paper critiques a recent measurement of the 15O(alpha,gamma)19Ne reaction rate, highlighting issues with the data's reliability and internal consistency, which impact understanding of nuclear burning on neutron stars.

Contribution

It identifies flaws in the previous measurement's data analysis and questions the validity of its conclusions on astrophysical reaction rates.

Findings

The alpha decay branching ratio for the 4.03 MeV state is unreliable.

The reaction rate calculation is based on questionable data.

There is an internal inconsistency in the original analysis.

Abstract

A recently published letter reports a measurement of alpha decay from states in 19Ne at excitation energies below 4.5 MeV. The measured alpha decay branching ratios B_alpha are used to calculate the astrophysical rate of the 15O(alpha,gamma)19Ne reaction and to draw conclusions regarding the transition between steady state and unstable nuclear burning on accreting neutron stars. Here I show that the calculated astrophysical reaction rate is based on an unreliable value of B_alpha for the 4.03 MeV state and point out a serious internal inconsistency in the letter's treatment of low statistics alpha decay measurements.