Kepler will monitor enough stars that it is likely to detect single transits of planets with periods longer than the mission lifetime .
We show that by combining the Kepler photometry of such transits with precise radial velocity ( RV ) observations taken over \sim 3 months , and assuming circular orbits , it is possible to estimate the periods of these transiting planets to better than 20 % ( for planets with radii greater than that of Neptune ) and the masses to within a factor of 2 ( for planet masses m _ { p } \geq M _ { Jup } ) .
We also explore the effects of eccentricity on our estimates of these uncertainties .