The influence of accretion rate and metallicity on thermonuclear bursts: predictions from KEPLER models

Abstract

Using the KEPLER hydrodynamics code, 464 models of thermonuclear X-ray bursters were performed across a range of accretion rates and compositions. We present the library of simulated burst profiles from this sample, and examine variations in the simulated lightcurve for different model conditions. We find that the recurrence time varies as a power law against accretion rate, and measure its slope while mixed H/He burning is occurring for a range of metallicities, finding the power law gradient to vary from $\eta = 1.1$ to $1.24$. We also identify the accretion rates at which mixed H/He burning stops and a transition occurs to different burning regimes. We also explore how varying the accretion rate and metallicity affects burst morphology in both the rise and tail.