the total time that must be devoted to exoplanet detection.

The study presented here focuses solely on broadband detections; we do not include spectral characterization time for any of the detected exoEarth candidates. The spectral characterization time depends on the bandpasses required for water and biosignature detection and the spectral resolving power, which in turn require well-defined mission science goals. In addition, the spectral characterization time can depend strongly on the observational procedure, e.g., will low resolution spectra be obtained for every potential point source to help discriminate between planets and background objects, or will spectra only be obtained after common proper motion is established? These complicating factors require additional analysis that is beyond the scope of this paper. We note that in the case $\eta_{\earth} \lesssim 0.1$, as we will assume, the spectral characterization time is a modest fraction of the total time budget because the proportion of exoEarth candidate spectra obtained to stars imaged is relatively small, and in the case of single-visit studies, as discussed below, the yield scales weakly with mission lifetime. Therefore, spectral characterization time should not greatly impact the single-visit yield estimates from this study.

Finally, we observe each star only once and ignore 