A New Method for Determining the Stability of Material Accreting onto Neutron Stars

Type I X-ray bursts are very common in neutron star X-ray binaries. We have carried out a global linear stability analysis of the accumulating fuel on the surface of a compact star and the underlying crust to identify the conditions under which thermonuclear bursts are triggered. Our analysis, which improves on previous calculations, reproduces the gross observational trends of bursts in neutron star systems as well as previous theoretical results. We also probe in detail the properties of systems that border on the edge of stable nuclear burning and find that our theoretical analysis reproduces some of the puzzling phenomena revealed by EXOSAT observations of systems on this boundary.