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A number of X-ray binaries exhibit clear evidence for the presence of diskwinds in the high/soft state. A promising driving mechanism for these outflowsis mass loss driven by the thermal expansion of X-ray heated material in theouter disk atmosphere. Higginbottom \& Proga recently demonstrated that theproperties of thermally-driven winds depend critically on the shape of thethermal equilibrium curve, since this determines the thermal stability of theirradiated material. For a given spectral energy distribution, the thermalequilibrium curve depends on exact balance between the various heating andcooling mechanisms at work. Most previous work on thermally-driven disk windsrelied an analytical approximation to these rates. Here, we use thephotoionization code \textsc{cloudy} to generate realistic heating and coolingrates which we then use in a 2.5D hydrodynamic model computed in ZEUS tosimulate thermal winds in a typical black-hole X-ray binary. We find that theseheating and cooling rates produce a significantly more complex thermalequilibrium curve, with dramatically different stability properties. Theresulting flow, calculated in the optically thin limit, is qualitativelydifferent from flows calculated using approximate analytical rates.Specifically, our thermal disk wind is much denser and slower, with a mass-lossrate that is a factor of two higher and characteristic velocities that are afactor of three lower. The low velocity of the flow -- $v_{max} \simeq200$~km~s$^{-1}$ -- may be difficult to reconcile with observations. However,the high mass-loss rate -- 15$\times$ the accretion rate -- is promising, sinceit has the potential to destabilize the disk. Thermally-driven disk winds maytherefore provide a mechanism for state changes.

Thermal Disk Winds in X-ray Binaries: Realistic Heating and Cooling Rates Give Rise to Slow, but Massive Outflows