– 15 – with secondaries as massive as the Kepler targets. Simulation 2 applies to intermediate-age populations. We average the results of these two simulations. In each case we average over the common envelope efficiency factors and also over the prescription for the value of δ. Including stellar systems with higher mutiplicity would increase the numbers of systems with white dwarfs in close orbits. The calculations described above suggest that Kepler may identify transits in roughly a thousand mass-transfer end states. Each case provides a unique way to measure the white dwarf radius, luminosity and temperature, and even to explore its atmosphere. This is all in addition to the standard “bag of tricks” that can be applied to any white dwarf in a binary. The ability to conduct a large number of such studies in a uniform way will determine the properties of the white dwarfs in terms of the mass lost history of their progenitors. With regard to mass loss histories, Kepler studies will establish the relative frequency of common envelope evolution and provide useful data points for determining the best way to compute common envelope evolution in terms of the properties of the binary at the time the dynamical instability was triggered. The range of systems producing stable mass transfer will also be better understood, including the all-important fraction, β, of material that can be retained by a main-sequence accretor. Most of the Kepler stars are field stars. Studying the Kepler blue stragglers will provide empirical insight into the contribution of ordinary binary evolution to the creation of blue stragglers. This will allow the contribution of stellar interactions in clusters to be better understood, since both primordial binaries and binaries formed or altered through interactions can produce blue stragglers. Finally, the white-dwarf/main-sequence binaries studied by Kepler will experience a second phase of interaction when the main-sequence star of today evolves and begins to transfer matter to the white dwarf. These systems will be novae, some may become double- degenerates that eventually merge, and some may even experience Type Ia supernovae, or accretion-induced collapse, through either the single-degenerate or double-degenerate chan- nel. Kepler will identify a set of these systems that can be studied in a unique way. and N ce transit = N detect monitored 135 , 000 [ 395 ± 32 ] (5) N mt transit = N detect monitored 135 , 000 [ 338 ± 143 ] (6) 3.3. Science Returns