  The effect of the stellar flux on exoplanetary systems is becoming an
increasingly important property as more planets are discovered in the Habitable
Zone (HZ). The Kepler mission has recently uncovered circumbinary planets with
relatively complex HZs due to the combined flux from the binary host stars.
Here we derive HZ boundaries for circumbinary systems and show their dependence
on the stellar masses, separation, and time while accounting for binary orbital
motion and the orbit of the planet. We include stability regimes for planetary
orbits in binary systems with respect to the HZ. These methods are applied to
several of the known circumbinary planetary systems such as Kepler-16, 34, 35,
and 47. We also quantitatively show the circumstances under which single-star
approximations break down for HZ calculations.
