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Direct imaging of exoplanets presents a formidable technical challenge owing to the small angular separation and high contrast between exoplanets and their host stars. High Dispersion Coronagraphy (HDC) is a pathway to achieve unprecedented…

Earth and Planetary Astrophysics · Physics 2017-04-05 Ji Wang , Dimitri Mawet , Garreth Ruane , Renyu Hu , Bjorn Benneke

We present a promising approach to the extremely fast sensing and correction of small wavefront errors in adaptive optics systems. As our algorithm's computational complexity is roughly proportional to the number of actuators, it is…

Instrumentation and Methods for Astrophysics · Physics 2016-11-26 Christoph U. Keller , Visa Korkiakoski , Niek Doelman , Rufus Fraanje , Raluca Andrei , Michel Verhaegen

State-of-the-art coronagraphs employed on extreme adaptive optics enabled instruments, are constantly improving the contrast detection limit for companions at ever closer separations to the host star. In order to constrain their properties…

Instrumentation and Methods for Astrophysics · Physics 2015-11-11 Nemanja Jovanovic , Olivier Guyon , Frantz Martinache , Prashant Pathak , Janis Hagelberg , Tomoyuki Kudo

Extreme adaptive optics systems are now in operation across the globe. These systems, capable of high order wavefront correction, deliver Strehl ratios of 90% in the near-infrared. Originally intended for the direct imaging of exoplanets,…

Instrumentation and Methods for Astrophysics · Physics 2016-11-09 Nemanja Jovanovic , Christian Schwab , Nick Cvetojevic , Olivier Guyon , Frantz Martinache

Speckle Noise is the dominant source of error in high contrast imaging with adaptive optics system. We discuss the potential for wavefront sensing telemetry to calibrate speckle noise with sufficient precision and accuracy so that it can be…

Imaging exo-Earths is an exciting but challenging task because of the 10^-10 contrast ratio between these planets and their host star at separations narrower than 100 mas. Large segmented aperture space telescopes enable the sensitivity…

A space telescope capable of high-contrast imaging has been recognized as the avenue toward finding terrestrial planets around nearby Sun-like stars and characterizing their potential habitability. It is thus essential to quantify the…

Earth and Planetary Astrophysics · Physics 2022-06-01 Mario Damiano , Renyu Hu

Over the past decade, the high-contrast observation of disks and gas giant planets around nearby stars has been made possible on ground-based instruments using extreme adaptive optics (XAO). While these facilities produce images with a…

Instrumentation and Methods for Astrophysics · Physics 2024-12-11 M. N'Diaye , A. Vigan , B. Engler , M. Kasper , K. Dohlen , S. Leveratto , J. Floriot , M. Marcos , C. Bailet , P. Bristow

Context. Direct imaging of exoplanets takes advantage of state-of-the-art adaptive optics (AO) systems, coronagraphy, and post-processing techniques. Coronagraphs attenuate starlight to mitigate the unfavorable flux ratio between an…

Instrumentation and Methods for Astrophysics · Physics 2022-09-21 Axel Potier , Johan Mazoyer , Zahed Wahhaj , Pierre Baudoz , Gael Chauvin , Raphael Galicher , Garreth Ruane

Context. In the context of direct imaging of exoplanets, coronagraphs are commonly proposed to reach the required very high contrast levels. However, wavefront aberrations induce speckles in their focal plane and limit their performance.…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Johan Mazoyer , Pierre Baudoz , Raphaël Galicher , Gérard Rousset

Direct imaging of exoplanets represents a challenge for astronomical instrumentation due to the high-contrast ratio and small angular separation between the host star and the faint planet. Multi-star systems pose additional challenges for…

Instrumentation and Methods for Astrophysics · Physics 2017-11-15 Dan Sirbu , Sandrine Thomas , Ruslan Belikov , Eduardo Bendek

The Optimal Optical Coronagraph (OOC) Workshop held at the Lorentz Center in September 2017 in Leiden, the Netherlands, gathered a diverse group of 25 researchers working on exoplanet instrumentation to stimulate the emergence and sharing…

We present a novel method for direct detection and characterization of exoplanets from space. This method uses four collecting telescopes, combined with phase chopping and a spectrometer, with observations on only a few baselines rather…

Earth and Planetary Astrophysics · Physics 2015-05-27 Taro Matsuo , Wesley A. Traub , Makoto Hattori , Motohide Tamura

One of the top remaining science challenges in astronomical optics is the direct imaging and characterization of extrasolar planets and planetary systems. Directly imaging exoplanets from ground-based observatories requires combining…

Instrumentation and Methods for Astrophysics · Physics 2021-10-04 Alexander T Rodack , Richard A Frazin , Jared R Males , Olivier Guyon

Adaptive optics is a technique mostly used on large telescopes. It turns out to be challenging for smaller telescopes (0.5~2m) due to the small isoplanatic angle, small subapertures and high correction speeds needed at visible wavelengths,…

Instrumentation and Methods for Astrophysics · Physics 2023-10-12 Olivier Lai , Mark Chun , Stefan Kuiper , Niek Doelman , Marcel Carbillet , Mamadou N'Diaye , Frantz Martinache , Lyu Abe , Jean-Pierre Rivet , Dirk Schmidt

Extra-solar planets direct imaging is now a reality with the deployment and commissioning of the first generation of specialized ground-based instruments (GPI, SPHERE, P1640 and SCExAO). These systems allow of planets $ 10 ^ 7 $ times…

Instrumentation and Methods for Astrophysics · Physics 2015-09-16 Sandrine J. Thomas , Ruslan Belikov , Eduardo Bendek

The major source of noise in high-contrast imaging is the presence of slowly evolving speckles that do not average with time. The temporal stability of the point-spread-function (PSF) is therefore critical to reach a high contrast with…

Instrumentation and Methods for Astrophysics · Physics 2018-07-03 J. Milli , T. Banas , D. Mouill , D. Mawet , J. H. Girard , A. Vigan , A. Boccaletti , M. Kasper , Z. Wahhaj , A. -M. Lagrange , J. -L. Beuzit , T. Fusco , J. -F. Sauvage , R. Galicher

The Astro2020 decadal survey recommended an infrared, optical, ultra-violet (IR/O/UV) telescope with a $\sim$6~m inscribed diameter and equipped with a coronagraph instrument to directly image exoEarths in the habitable zone of their host…

Extreme wavefront correction is required for coronagraphs on future space telescopes to reach 1e-8 or better starlight suppression for the direct imaging and characterization of exoplanets in reflected light. Thus, a suite of wavefront…

Direct imaging of extra-solar planets has now become a reality, especially with the deployment and commissioning of the first generation of specialized ground-based instruments such as the GPI, SPHERE, P1640 and SCExAO. These systems will…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Sandrine J. Thomas , Ruslan Belikov , Eduardo Bendek