ACCRETION RATES IN X-RAY BURSTING SOURCES

We present estimates for the accretion rates in 13 X-ray bursting sour ces that exhibit photospheric expansion, basing on theoretical models of stationary, radiatively driven winds from neutron stars. The relati vely high values obtained, M(acc) greater than or similar to 10(-9) M. yr-1, are in accordance with theoretical limits for unstable helium b urning and, at the same time, almost never exceed the '' dynamical '' limit for stationary accretion, approximately 10M(Edd). The only excep tions are 1820-30, already known to be a very peculiar object, and 160 8-522; there are indications, however, that in both sources, accretion could be nonstationary.