Sensitivity of Type I X-ray bursts to rp-process reaction rates

First steps have been taken in a more comprehensive study of the dependence of observables in Type I X-ray bursts on uncertain (p,g ) reaction rates along the rp -process path. We use the multizone hydrodynamics code KEPLER which implicitly couples a full nuclear reaction network of more than 1000 isotopes, as needed, to follow structure and evolution of the X-ray burst layer and its ashes. This allows us to incorporate the full rp -process network, including all relevant nuclear reactions, and individually study changes in the X-ray burst light curves when modifying selected key nuclear reaction rates. In this work we considered all possible proton captures to nuclei with 10 < Z < 28 and N ≤ Z. When varying individual reaction rates within a symmetric full width uncertainty of a factor of 10⁴, early results for some rates show changes in the burst light curve as large as 10 percent of peak luminosity. This change is large enough to be detectable by current X-ray burst light curve observations. More precise reaction rates are therefore needed to test current X-ray burst models, particularly of the burst rise, with observational data and to constrain astrophysical parameters.