Direct imaging of exoplanets in the habitable zone with adaptive optics

TL;DR

This paper discusses the challenges and prospects of directly imaging habitable exoplanets using adaptive optics on giant ground-based telescopes, highlighting recent observational results and technological considerations.

Contribution

It provides a review of habitable zone definitions, discusses differences in direct imaging approaches, and presents preliminary observational results targeting Alpha Centauri A.

Findings

Achieved high-contrast imaging of Alpha Centauri A's habitable zone

Identified challenges in adaptive optics for small angular separations

Demonstrated potential for imaging nearby habitable exoplanets

Abstract

One of the primary goals of exoplanet science is to find and characterize habitable planets, and direct imaging will play a key role in this effort. Though imaging a true Earth analog is likely out of reach from the ground, the coming generation of giant telescopes will find and characterize many planets in and near the habitable zones (HZs) of nearby stars. Radial velocity and transit searches indicate that such planets are common, but imaging them will require achieving extreme contrasts at very small angular separations, posing many challenges for adaptive optics (AO) system design. Giant planets in the HZ may even be within reach with the latest generation of high-contrast imagers for a handful of very nearby stars. Here we will review the definition of the HZ, and the characteristics of detectable planets there. We then review some of the ways that direct imaging in the HZ will be different from the typical exoplanet imaging survey today. Finally, we present preliminary results from our observations of the HZ of {\alpha} Centauri A with the Magellan AO system's VisAO and Clio2 cameras.