Stellar reaction rate of 55Ni(p, γ)56Cu in Type I X-ray bursts

Abstract

$$^{56}\hbox {Cu}$$ is close to the waiting-point nucleus $$^{56}\hbox {Ni}$$ and lies on the rapid proton capture (rp) process path in Type I X-ray bursts (XRBs). In this work, we obtained a revised thermonuclear reaction rate of $$^{55}\hbox {Ni}(\hbox {p},\gamma )^{56}\hbox {Cu}$$ in the temperature region relevant to XRBs. This rate was recalculated based on the recent experimental level structure in $$^{56}\hbox {Cu}$$ , the recently measured proton separation energy of $$S_\text {p}$$ = 579.8(7.1) keV, together with shell-model calculation, and the mirror nuclear structure in $$^{56}\hbox {Co}$$ . The associated uncertainties in the rates were estimated by a Monte Carlo method. Our revised rate is significantly different from the recent results, which were partially based on experimental results; in addition, we found that a result in a previous work was incorrect. We recommend our revised rate to be incorporated in the future astrophysical network calculations.