Adaptive optics in high-contrast imaging

Abstract

The development of adaptive optics (AO) played a major role in modern astronomy over the last three decades. By compensating for the atmospheric turbulence, these systems enable to reach the diffraction limit on large telescopes. In this review, we will focus on high contrast applications of adaptive optics, namely, imaging the close vicinity of bright stellar objects and revealing regions otherwise hidden within the turbulent halo of the atmosphere to look for objects with a contrast ratio lower than 10^-4 with respect to the central star. Such high-contrast AO-corrected observations have led to fundamental results in our current understanding of planetary formation and evolution as well as stellar evolution. AO systems equipped three generations of instruments, from the first pioneering experiments in the nineties, to the first wave of instruments on 8m-class telescopes in the years 2000, and finally to the extreme AO systems that have recently started operations. Along with high-contrast techniques, AO enables to reveal the circumstellar environment: massive protoplanetary disks featuring spiral arms, gaps or other asymmetries hinting at on-going planet formation, young giant planets shining in thermal emission, or tenuous debris disks and micron-sized dust leftover from collisions in massive asteroid-belt analogs. After introducing the science case and technical requirements, we will review the architecture of standard and extreme AO systems, before presenting a few selected science highlights obtained with recent AO instruments.

24 pages, 14 figures

References in corpus (18)

• The Gemini Planet Imager: First Light
• Theoretical Limits on Extrasolar Terrestrial Planet Detection with Coronagraphs
• Lucky Imaging: High Angular Resolution Imaging in the Visible from the Ground
• Polarimetry with the Gemini Planet Imager: Methods, Performance at First Light, and the Circumstellar Ring around HR 4796A
• Instrumentation for the detection and characterization of exoplanets
• Temporal Evolution of Coronagraphic Dynamic Range, and Constraints on Companions to Vega
• Confidence Level and Sensitivity Limits in High Contrast Imaging
• The VAMPIRES instrument: Imaging the innermost regions of protoplanetary disks with polarimetric interferometry
• Magellan Adaptive Optics first-light observations of the exoplanet $\beta$ Pic b. I. Direct imaging in the far-red optical with MagAO+VisAO and in the near-IR with NICI
• First On-Sky High Contrast Imaging with an Apodizing Phase Plate
• Five Debris Disks Newly Revealed in Scattered Light from the HST NICMOS Archive
• Extreme adaptive optics imaging with a clear and well-corrected off-axis telescope sub-aperture
• Archival Legacy Investigations of Circumstellar Environments: Overview and First Results
• New constraints on the dust surrounding HR 4796A
• The Gemini NICI Planet-Finding Campaign: The Offset Ring of HR 4796 A
• Early Results from VLT-SPHERE: Long-Slit Spectroscopy of 2MASS 0122-2439B, a Young Companion Near the Deuterium Burning Limit
• A Quick Study of Science Return from Direct Imaging Exoplanet Missions: Detection and Characterization of Circumstellar Material with an AFTA or EXO-C/S CGI
• Image quality and high contrast improvements on VLT/NACO