A contour plot of the error in ﹩\mathrm{log}{g}_{* }﹩ as a function of the percent errors in M _* and R _*, derived from Equation (22). A typical spectroscopic constraint of 0.1 dex corresponds to 2% error for a solar-type star. When we get systematic-error-dominated values for M _* and R _* (without a transit density), we still do about 2× better than spectroscopy.