Adaptive Optics Observations of Exoplanets, Brown Dwarfs, & Binary Stars

TL;DR

This paper discusses advancements in high contrast imaging techniques, including adaptive optics and aperture masking interferometry, for observing exoplanets, brown dwarfs, and binary stars, highlighting upcoming dedicated instruments and their scientific potential.

Contribution

The paper reviews recent and upcoming high contrast imaging instruments and techniques, emphasizing their capabilities for characterizing exoplanets and brown dwarfs, and demonstrates aperture masking interferometry's effectiveness.

Findings

Aperture masking detects massive, young planets at 3-30 AU.

Upcoming instruments will provide spectral and polarimetric data.

Recent observations of HR 8799 showcase technique power.

Abstract

The current direct observations of brown dwarfs and exoplanets have been obtained using instruments not specifically designed for overcoming the large contrast ratio between the host star and any wide-separation faint companions. However, we are about to witness the birth of several new dedicated observing platforms specifically geared towards high contrast imaging of these objects. The Gemini Planet Imager, VLT-SPHERE, Subaru HiCIAO, and Project 1640 at the Palomar 5m telescope will return images of numerous exoplanets and brown dwarfs over hundreds of observing nights in the next five years. Along with diffraction-limited coronagraphs and high-order adaptive optics, these instruments also will return spectral and polarimetric information on any discovered targets, giving clues to their atmospheric compositions and characteristics. Such spectral characterization will be key to forming a detailed theory of comparative exoplanetary science which will be widely applicable to both exoplanets and brown dwarfs. Further, the prevalence of aperture masking interferometry in the field of high contrast imaging is also allowing observers to sense massive, young planets at solar system scales (~3-30 AU)---separations out of reach to conventional direct imaging techniques. Such observations can provide snapshots at the earliest phases of planet formation---information essential for constraining formation mechanisms as well as evolutionary models of planetary mass companions. As a demonstration of the power of this technique, I briefly review recent aperture masking observations of the HR 8799 system. Moreover, all of the aforementioned techniques are already extremely adept at detecting low-mass stellar companions to their target stars, and I present some recent highlights.