Accreting neutron stars in binary star system regularly
demonstrate outbursts of X-rays as pent up hydrogen and helium
fuel becomes unstable and burns explosively on the surface creating
proton-rich nuclei from the valley of stability and all the way
to the proton drip-line up to mass number A~100.
X-ray bursts have been observed since 1976 and by now many hundreds
of burst light-curves have been measured and catalogued. The specifics
of the light curve depends to a very large degree on knowing the
individual nuclear reactions which power the burst, and by using
a detailed model of the explosion one can even calculate backwards
and constrain unknown nuclear physics data down to individual
resonance strengths e.g. the 4.033 MeV level in O15(alpha,gamma)Ne19
by comparing model light curves to the observed light curves.
X-ray bursting neutron stars therefore provide a good complementary
"nuclear physics laboratory" easily reaching extreme
conditions which are difficult to obtain in terrestrial laboratories.
However, of the 63 known X-ray bursters only one(!) is quantitatively
well described by models. We are therefore building a next generation
model which also considers the previously neglected accretion
inflow, the magnetic field interaction and the lateral spreading
of the material and the lateral spreading of the burning front
in order to compare with more detailed observations.