Thermonuclear ¹⁷O(n, γ)¹⁸O Reaction Rate and Its Astrophysical Implications

A new thermonuclear $^{17}$O($n$,$\gamma$)$^{18}$O rate is derived based on a complete calculation of the direct-capture (DC) and resonant-capture contributions, for temperature region up to 2 GK astrophysical interest. We have firstly calculated DC subthreshold contributions in energy 1 MeV, estimated associated uncertainties by Monte-Carlo approach. It shows that present remarkably larger than adopted JINA REACLIB 0.01 $\sim$ GK, factor $\sim$80. The impacts our been examined both $s$-process $r$-process models. In main model which simulates flash-driven convective mixing metal deficient asymptotic giant branch stars, $^{18}$O $^{19}$F abundances interpulse phases are enhanced dramatically factors $\sim 20$--$40$ due rate. shows, however, this reaction hardly affects weak massive stars since $^{17}$O abundance never becomes significantly large stars. For nucleosynthesis, we studied collapsar neutron burst models, found effect can be neglected, although an interesting "loophole" owing rate, changes final nuclear if fission recycling not involved model, these significant differences almost completely washed out considered.