2000PASP..112.1330C

We examine a simple model to account for the observations during quiescence of the soft X-ray transients within the context of the standard accretion disk limit cycle. In our model the cooling front is not able to propagate completely to the inner edge of the accretion disk, so that a portion of the inner disk is always in the high state. The outer edge r_crit of this hot, ionized disk determines the rate of accretion and maximum temperature in the inner disk. We find that such a model is unable to account for the ROSAT observation by McClintock et al. of A0620-00 in quiescence: with r_crit constrained to be ∼10⁹ cm so as to reproduce the observed level of X-ray flux (∼10³¹ ergs.s^–1, or M{dot}∼10¹¹ g.s^–1, for an assumed accretion efficiency of ∼0.1), the inner effective temperature is about a factor of 10 too low (∼0.02 keV vs. ∼0.2 keV). This confirms the estimates of Narayan, McClintock, & Yi.