Sensitivity studies on the thermal beta plus decay and thermal neutrino loss rates in the multizone X-ray burst model MESA

Recently, it has been discovered that the beta+decay rates and neutrino loss rates of Ga-64 and Se-68 greatly affect the light curves and final abundances of X-ray bursts in a one-zone model in all circumstances. Here we further expand the study to the multizone model MESA and compare the results with observations of the bursting source GS 1826-24. It was found that the light curve of the modified beta decay rates of Ga-64 is more comparable to observations than the standard beta decays. The final mass fractions of the ashes of the X-ray bursts for elements with a mass number of 38 (Ar-38, Ca-38) are greatly modified because of the beta-Fdecay rate and neutrino loss rate of Se-68. They also produce more URCA nuclei, which may lead to stronger cooling in the neutron star crusts. Both the modified rates of Se-68 and Ga-64 make the recurrence times of the simulated X-ray bursts longer because they cause more energy loss than the standard rates and more time is needed to accumulate energy to trigger the bursts.