The relevance of prior inclination determination for direct imaging of Earth-like planets

TL;DR

This paper investigates how prior knowledge of a planet's orbital inclination enhances the efficiency of direct imaging missions for Earth-like exoplanets, emphasizing the importance of inclination determination methods.

Contribution

It quantifies the impact of inclination knowledge on imaging efficiency and discusses the potential of ground-based methods to improve mission outcomes.

Findings

Inclination knowledge has a greater impact than exozodiacal brightness.

Combining inclination and brightness measurements improves imaging efficiency.

Ground-based efforts can significantly aid space-based exoplanet imaging missions.

Abstract

Direct imaging and characterization of extrasolar Earth-like planets is strongly impacted by the orbital inclination of the planet to be studied, as a combination of pure geometrical effects and the impact of exozodiacal dust. Here, we perform simulations to quantify the impact of a priori knowledge of inclination for the efficiency of a typical coronagraphic or occulter-based mission. The relative impact and complementarity with prior knowledge of exozodiacal brightness down to achievable levels is examined and discussed. It is found that inclination has an even greater impact than the exozodiacal brightness, though the two have excellent complementarity. We also discuss different methods for inclination determination, and their respective applicability to the context of precursor science to an imaging mission. It is found that if technologically achievable, a combined effort to determine inclinations and exozodiacal brightnesses with ground-based facilities would substantially increase the efficiency of a space-based dedicated mission to image and characterize Earth-like planets.