http://arxiv.org/abs/1402.2612
We propose a science metric for pure-search missions of the scale of the Terrestrial Planet Finder. The metric is the expected number $N$ of discovered earthlike planets as a function of total exposure time $\Sigma\tau$. We estimate $N(\Sigma\tau)$ for a range of mission parameters: aperture $D=4-16$ m, inner working angle $IWA=0.0196”-0.3135”$, and $\Sigma\tau=10-1000$ d. Our technique involves (1) building a prioritized stack of all possible search observations of stars in the input catalog, including revisits, (2) constructing design reference missions by repeatedly selecting the observation with highest merit from the top of the stack, (3) estimating the density of $N$ by convolving the Bernoullian densities of executed observations, and (4) investigating the parametrical variations of $N$, $D$, $IWA$, and $\Sigma\tau$. For example, near the center of the range of parameters — at $D=8$ m, $IWA=0.0784”$, $\Sigma\tau=100$ d — we estimate $N=40$, that $N\sim\Sigma\tau^{0.272}$, and that a factor-two improvement in $D$, $IWA$ — or both — increases $N$ by factor 1.6, 2.95, or 4.0, correspondingly.
R. Brown
Wed, 12 Feb 14
62/67
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