# A Simple Depth of Search Metric for Exoplanet Imaging Surveys

## TL;DR

This paper introduces a fast, flexible method to estimate exoplanet imaging yields by separating instrument performance from planet distribution assumptions, and proposes a new star selection metric independent of planet occurrence models.

## Contribution

It presents a novel 'depth of search' metric for exoplanet imaging surveys and a star selection method that does not rely on assumed planet populations.

## Key findings

- Demonstrated the calculation of the depth of search for a WFIRST coronagraph design.
- Showed how to recover total mission completeness by convolving depth of search with occurrence rates.
- Provided a practical framework for optimizing exoplanet imaging surveys.

## Abstract

We present a procedure for calculating expected exoplanet imaging yields, which explicitly separates the effects of instrument performance from assumptions of planet distributions. This `depth of search' approach allows for fast recalculation of yield values for variations in instrument parameters. We also describe a new target star selection metric with no dependence on an assumed planet population that can be used as a proxy for single-visit completeness. This approach allows for the recovery of the total mission completeness via convolution of the depth of search grid with an equivalent grid of assumed occurrence rates and integration over the part of the grid representing the population of interest (e.g., Earth-like planets on habitable zone orbits, etc.). In this work, we discuss the practical details of calculating the depth of search and present results of such calculations for one design iteration of the WFIRST coronagraphs.