Search

Techniques and Instrumentation for Detection of Exoplanets X (2021) San Diego1 August 2021 through 5 August 2021, Code 172620.--Proceedings of SPIE - The International Society for Optical Engineering vol. 118232021 Article number 118230H, The James Webb Space Telescope (JWST) and its suite of instruments will offer significant capabilities towards the high contrast imaging of objects such as exoplanets, protoplanetary disks, and debris disks at short angular separations from their considerably brighter host stars. For the JWST user community to simulate and predict these capabilities for a given science case, the JWST Exposure Time Calculator (ETC) is the most readily available and widely used simulation tool. However, the ETC is not capable of simulating a range of observational features that can significantly impact the performance of JWST's high contrast imaging modes (e.g.Target acquisition offsets, temporal wavefront drifts, small grid dithers, and telescope rolls) and therefore does not produce realistic contrast curves. Despite the development of a range of more advanced software that includes some or all of these features, these instead lack in either a) instrument diversity, or b) accessibility for novice users, This project was supported by a grant from STScI (JWST-ERS-01386) under NASA contract NAS5-03127, With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709

NASA is developing starshade technology to Technology Readiness Level 5 within a directed activity called S5. The objective of S5 is to mature starshade technology to the level that exoplanet imaging missions, such as Starshade Rendezvous and HabEx, can begin the formulation phase. This paper outlines the S5 activity as a whole, to show how it closes all starshade technology gaps in a mutually consistent way. It serves as a companion paper to several other papers in this special section that report progress in specific starshade technologies.

Large surveys with new-generation high-contrast imaging instruments are needed to derive the frequency and properties of exoplanet populations with separations from ~5 to 300 au. A careful assessment of the stellar properties is crucial for a proper understanding of when, where, and how frequently planets form, and how they evolve. The sensitivity of detection limits to stellar age makes this a key parameter for direct imaging surveys. Aims. We describe the SpHere INfrared survey for Exoplanets (SHINE), the largest direct imaging planet-search campaign initiated at the VLT in 2015 in the context of the SPHERE Guaranteed Time Observations of the SPHERE consortium. In this first paper we present the selection and the properties of the complete sample of stars surveyed with SHINE, focusing on the targets observed during the first phase of the survey (from February 2015 to February 2017). This early sample composed of 150 stars is used to perform a preliminary statistical analysis of the SHINE data, deferred to two companion papers presenting the survey performance, main discoveries, and the preliminary statistical constraints set by SHINE. Methods. Based on a large database collecting the stellar properties of all young nearby stars in the solar vicinity (including kinematics, membership to moving groups, isochrones, lithium abundance, rotation, and activity), we selected the original sample of 800 stars that were ranked in order of priority according to their sensitivity for planet detection in direct imaging with SPHERE. The properties of the stars that are part of the early statistical sample wererevisited, including for instance measurements from the Gaia Data Release 2. Rotation periods were derived for the vast majority of the late-type objects exploiting TESS light curves and dedicated photometric observations. Results. The properties of individual targets and of the sample as a whole are presented. © ESO 2021. SPHERE is an instrument designed and built by a consortium consisting of IPAG (Grenoble, France), MPIA (Heidelberg, Germany), LAM (Marseille, France), LESIA (Paris, France), Laboratoire Lagrange (Nice, France), INAF – Osservatorio di Padova (Italy), Observatoire de Genève (Switzerland), ETH Zürich (Switzerland), NOVA (Netherlands), ONERA (France) and ASTRON (Netherlands) in collaboration with ESO. SPHERE was funded by ESO, with additional contributions from CNRS (France), MPIA (Germany), INAF (Italy), FINES (Switzerland) and NOVA (Netherlands). SPHERE also received funding from the European Commission Sixth and Seventh Framework Programmes as part of the Optical Infrared Coordination Network for Astronomy (OPTICON) under grant number RII3-Ct-2004-001566 for FP6 (2004–2008), grant number 226 604 for FP7 (2009–2012) and grant number 312430 for FP7 (2013–2016). This research has made use of the SIMBAD database and Vizier services, operated at CDS, Strasbourg, France and of the Washington Double Star Catalog maintained at the US Naval Observatory. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This paper includes data collected with the TESS mission, obtained from the MAST data archive at the Space Telescope Science Institute (STScI). Funding for the TESS mission is provided by the NASA Explorer Program. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5–26555. This paper has made use of data products available in ESO archive. Program ID: 60.A-9036(A); 072.C-0488(E) (PI Mayor), 074.C-0364(A) (PI Robichon), 074.C-0037(A) (PI Gunther), 075.C-0202(A) (PI Gunther), 075.C-0689(A) (PI Galland), 076.C-0010(A) (PI Gunther), 077.C-0012(A) (PI Gunther), 077.C-0295(D) (PI Galland), 078.D-0245(C) (PI Dall), 079.C-0046(A) (PI Gunther), 080.D-0151(A) (PI Hatzes), 080.C-0712(A) (PI Desort), 180.C-0886(A) (PI Bonfils), 082.C-0718(B) (PI Bonfils), 082.C-0427(A) (PI Doellinger), 082.C-0390(A) (PI Weise), 183.C-0437(A) (PI Bonfils), 083.C-0794(A) (PI Chauvin), 084.C-1039(A) (PI Chauvin), 184.C-0815(B) (PI Desort), 089.C-0732(A) (PI Lo Curto), 191.C-0873(D) (PI Bonfils), 192.C-0224(A) (PI Lagrange), 097.C-0864(B) (PI Lannier), 098.C-0739(A) (PI Lagrange), 099.C-0205(A) (PI Lagrange), 099.C-0458(A) (PI Lo Curto), 1101.C-0557(A) (PI Lagrange). We have used data from the WASP public archive in this research. The WASP consortium comprises of the University of Cambridge, Keele University, University of Leicester, The Open University, The Queen’s University Belfast, St. Andrews University and the Isaac Newton Group. Funding for WASP comes from the consortium universities and from the UK’s Science and Technology Facilities Council. Based on data retrieved from the SOPHIE archive at Observatoire de Haute-Provence (OHP), available at http://atlas.obs-hp.fr/sophie/. We thank the anonymous referee for useful comments. S.D., V.D., D.M. and R.G. acknowledge the support by INAF/Frontiera through the “Progetti Premiali” funding scheme of the Italian Ministry of Education, University, and Research, the PRIN-INAF 2019 “Planetary systems at young ages” (PLATEA) and the ASI-INAF agreement n.2018-16-HH.0. AV acknowledges funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 757561). A.M.L. acknowledges funding from Agence Nationale de la Recherche (France) under contract number ANR-14-CE33-0018. J.C. was supported by SC Space Grant and Fulbright Colombia. M.B. acknowledges funding by the UK Science and Technology Facilities Council (STFC) grant no. ST/M001229.

METIS is one of the first three instruments for the ELT, Europe’s next-generation ground-based telescope. It will offer imaging, coronagraphy and spectroscopy in the L, M and N bands for general-purpose science in astrophysics. Among its main science drivers are circumstellar disks and extrasolar planets observations, which requires demanding high contrast imaging techniques. In that framework, METIS will be equipped with state-of-the-art phase mask coronagraphs: Apodizing Phase Plate (APP) and Annular Grooves Phase Mask (AGPM). Manufacturing the AGPM coronagraphs is a complex process that requires performance assessment with specific testing before implementation into the instrument. At Department of Astrophysics (CEA Saclay, France), responsible for the testing of the N-band AGPMs, a previously available test bench with a telescope simulator and cryogenic facility has been upgraded to comply with the AGPM tests requirements. This paper presents these requirements and describes the test bench design adopted. Then, based on preliminary results, we discuss the original solutions that permitted to reach our goals.

The NEW EARTH Laboratory (NRC Extreme Wavefront control for Exoplanet Adaptive optics Research Topics at Herzberg) has recently been completed at NRC in Victoria. NEW EARTH is the first Canadian test-bed dedicated to high-contrast imaging. The bench optical design allows a wide range of applications that could require turbulent phase screens, segmented pupils, or custom coronagraphic masks. Super-polished off-axis parabolas are implemented to minimize optical aberrations, in addition to a 468-actuator ALPAO deformable mirror and a Shack Hartmann WFS. The laboratory’s immediate goal is to validate the Fast Atmospheric Self-coherent camera Technique (FAST). The first results of this technique obtained in the NEW EARTH laboratory with a Tilt-Gaussian-Vortex focal plane mask, a reflective Lyot stop and Coherent Differential Imaging are encouraging. Future work will be aimed at expanding this technique to broader wavebands in the context of extremely large telescopes and at visible bands for space-based observatories.

International audience; The observation and characterization of the exoplanets and planetary architectures are crucial to broaden and complete our vision of the formation and evolution of planetary systems but also of the physics of the atmospheres of the exoplanets. In this context, MICADO, the European Extremely Large Telescope first-light imager will be equipped with an imaging mode dedicated to exoplanets and a long slit spectroscopy mode (R = 20 000) with an unbeaten sensitivity. The 5-fold increase in the angular resolution between the current instruments like SPHERE or GPI and MICADO will allow a quantitative and qualitative jump on the study of these planetary systems. Among the promising scientific cases: the characterization of exoplanets in synergy with GAIA and radial velocity surveys (eg SPIRou), the study of disk-planet interactions, the high-resolution study of exoplanetary atmospheres.

Direct detection and detailed characterization of exoplanets using extreme adaptive optics (ExAO) is a key science goal of future extremely large telescopes (ELTs). However, wavefront errors will limit the sensitivity of this endeavor. Limitations for ground-based telescopes arise from both quasi-static and residual AO-corrected atmospheric wavefront errors, the latter of which generates short-lived aberrations that will average into a halo over a long exposure. We have developed and tested the framework for a solution to both of these problems using the self-coherent camera (SCC), to be applied to ground-based telescopes, called the Fast Atmospheric SCC Technique (FAST). In this paper we present updates of new and ongoing work for FAST, both in numerical simulation and in the laboratory. We first present numerical simulations that illustrate the scientific potential of FAST, including, with current 10-m telescopes, the direct detection of exoplanets reflected light and exo-Jupiters in thermal emission and, with future ELTs, the detection of habitable exoplanets. In the laboratory, we present the first characterizations of our proposed, and now fabricated, coronagraphic masks., 6th International Conference on Adaptive Optics for Extremely Large Telescopes, AO4ELT 2019, June 9-14, 2019, Quebec City, Canada

The Habitable-Exoplanet Observatory (HabEx) is a candidate flagship mission being studied by NASA and the astrophysics community in preparation of the 2020 Decadal Survey. The first HabEx mission concept that has been studied is a large (~4m) diffraction-limited optical space telescope, providing unprecedented resolution and contrast in the optical, with extensions into the near ulttraviolet and near infrared domains. We report here on our team’s efforts in defining a scientifically compelling HabEx mission that is technologically executable, affordable within NASA’s expected budgetary envelope, and timely for the next decade. We also briefly discuss our plans to explore less ambitious, descoped missions relative to the primary mission architecture discussed here.

Starshades provide a leading technology to enable the direct detection and spectroscopic characterization of Earth-like exoplanets. Two key aspects to advancing starshade technology are the demonstration of starlight suppression at science-enabling levels and validation of optical models at this high level of suppression. These technologies are addressed in current efforts underway at the Princeton Starshade Testbed. Recent experimental data suggest we are observing the effects of vector (non-scalar) diffraction, which are limiting the starshade's performance and preventing the scalar optical models from agreeing with experimental results at the deepest levels of suppression. This report outlines a model developed to simulate vector diffraction in the testbed using a full solution to Maxwell's equations propagating through narrow features of the starshade. We find that experimental results can be explained by vector diffraction as light traverses the thickness of the starshade mask and that our model is in rough agreement with observations. We provide simulation results of a number of starshade geometries as a first attempt to understand the relation of these effects to properties of the starshade masks. Finally, we outline a number of possible solutions aimed to minimize vector effects and to allow us to reach our milestone of 10-9 suppression.

The Planetary Systems Imager (PSI) is a modular instrument optimized for direct imaging and characterization of exoplanet and disks with the Thirty Meter Telescope (TMT). PSI will operate across a wide wavelength range (≈0.6 - 5μm) to image exoplanets and circumstellar disks in both reflected light and thermal emission. Thanks to the TMT’s large collecting area, PSI will have the sensitivity to directly image and spectrally characterize large gaseous planets with unprecedented sensitivity. PSI will also be capable of imaging rocky planets in the habitable zones of the nearest M-type stars in reflected light and search for biomarkers in their atmospheres. Imaging habitable planets in reflected light is PSI’s most challenging goal, requiring high contrast imaging (HCI) capabilities well beyond what current instruments achieve. This science goal drives PSI’s wavefront sensing and control requirements and defines the corresponding architecture discussed in this paper. We show that PSI must deliver 1e-5 image contrast ≈15 mas separation at λ ≈ 1μm-1.5μm, and that a conventional extreme-AO architecture relying on a single high speed wavefront sensor (WFS) is not sufficient to meet this requirement. We propose a wavefront control architecture relying on both visible light (λ < 1.1 μm) sensing to optimize sensitivity, and near-IR (λ > 1.1 μm) sensors to address wavefront chromaticity terms and provide high contrast imaging capability. We show that this combination will enable speckle halo suppression at the < 1e-5 raw contrast level in near-IR, allowing detection and spectroscopic characterization of potentially habitable exoplanets orbiting nearby M-type stars., Adaptive Optics Systems VI, June 10-15, 2018, Austin, USA, Series: Proceedings of SPIE; no. 10703

MagAO-X is an entirely new extreme adaptive optics system for the Magellan Clay 6.5 m telescope, funded by the NSF MRI program starting in Sep 2016. The key science goal of MagAO-X is high-contrast imaging of accreting protoplanets at Hα. With 2040 actuators operating at up to 3630 Hz, MagAO-X will deliver high Strehls (> 70%), high resolution (19 mas), and high contrast (< 1 × 10^(-4)) at Hα (656 nm). We present an overview of the MagAO-X system, review the system design, and discuss the current project status.

SHARK-VIS, the LBT forthcoming high-contrast imager, is undergoing its fabrication phase and will see its first light in Q4-2019. By exploiting the outstanding performance of the LBT SOUL adaptive optics in the range of wavelength from 400 to 1000 nm, the instrument is expected to provide breakthrough science results in different fields, from exoplanets detection and characterization, to star formation with resolutions around 15mas and a contrast larger than 1e-5 at 100mas of separation. This will be possible thanks to the unprecedented performances of the LBT extreme AO system and the instrument fast-frame-rate acquisition as already demonstrated by preliminary tests on-sky. In this contribution, we will review the main technical aspects of the instrument and present the current project status.

With the development of high contrast imaging techniques and instruments, vast efforts have been devoted during the past decades to detect and characterize lighter, cooler and closer companions to nearby stars, and ultimately image new planetary systems. Complementary to other planet-hunting techniques, this approach has opened a new astrophysical window to study the physical properties and the formation mechanisms of brown dwarfs and planets. In this review, I will briefly describe the different observing techniques and strategies used, the main samples of targeted nearby stars, finally the main results obtained so far about exoplanet discoveries characterization of their physical properties, and study of their occurrence and possible formation and evolution mechanisms.

NASA WFIRST mission has planned to include a coronagraph instrument to find and characterize exoplanets. Masks are needed to suppress the host star light to better than 10-8 – 10-9 level contrast over a broad bandwidth to enable the coronagraph mission objectives. Such masks for high contrast coronagraphic imaging require various fabrication technologies to meet a wide range of specifications, including precise shapes, micron scale island features, ultra-low reflectivity regions, uniformity, wave front quality, etc. We present the technologies employed at JPL to produce these pupil plane and image plane coronagraph masks, and lab-scale external occulter masks, highlighting accomplishments from the high contrast imaging testbed (HCIT) at JPL and from the high contrast imaging lab (HCIL) at Princeton University. Inherent systematic and random errors in fabrication and their impact on coronagraph performance are discussed with model predictions and measurements.

NASA's Technology Development for Exoplanet Missions program; JPL's Exoplanet Exploration Program

Transition disks, protoplanetary disks with inner clearings, are promising objects in which to directly image forming planets. The high contrast imaging technique of non-redundant masking is well posed to detect planetary mass companions at several to tens of AU in nearby transition disks. We present non-redundant masking observations of the T Cha and LkCa 15 transition disks, both of which host posited sub-stellar mass companions. However, due to a loss of information intrinsic to the technique, observations of extended sources (e.g. scattered light from disks) can be misinterpreted as moving companions. We discuss tests to distinguish between these two scenarios, with applications to the T Cha and LkCa 15 observations. We argue that a static, forward-scattering disk can explain the T Cha data, while LkCa 15 is best explained by multiple orbiting companions., Comment: SPIE conference proceeding

Over 3000 exoplanets and hundreds of exoplanetary systems have been detected to date and we are now rapidly moving toward an era where the focus is shifting from detection to direct imaging and spectroscopic characterization of these new worlds and their atmospheres. NASA is currently studying several exoplanet characterization mission concepts for the 2020 Decadal Survey ranging from probe class to flagships. Detailed and comprehensive exoplanet characterization, particularly of exo-Earths, leading to assessment of habitability, or indeed detection of life, will require significant advances beyond the current state-of-the-art in high contrast imaging and starlight suppression techniques which utilize specially shaped precision optical elements to block the light from the parent star while controlling scattering and diffraction thus revealing and enabling spectroscopic study of the orbiting exoplanets in reflected light. In this paper we describe the two primary high contrast starlight suppression techniques currently being pursued by NASA: 1) coronagraphs (including several design variations) and 2) free-flying starshades. These techniques are rapidly moving from the technology development phase to the design and engineering phase and we discuss the prospects and projected performance for future exoplanet characterization missions utilizing these techniques coupled with large aperture telescopes in space.

Presently, dedicated instrument developments at large telescopes (SPHERE for the VLT, GPI for Gemini) are about to discover and explore self-luminous giant planets by direct imaging and spectroscopy. The next generation of 30m-40m ground-based telescopes, the Extremely Large Telescopes (ELTs), have the potential to dramatically enlarge the discovery space towards older giant planets seen in reflected light and ultimately even a small number of rocky planets. EPICS is a proposed instrument for the European ELT, dedicated to the detection and characterization of expolanets by direct imaging and spectroscopy. ESO recently launched a phase-A study for EPICS with a large European consortium which - by simulations and demonstration experiments - will investigate state-of-the-art diffraction and speckle suppression techniques to deliver highest contrasts. The final result of the study in 2010 will be a conceptual design and a development plan for the instrument. Here we present first results from the phase-A study and discuss the main challenges and science capabilities of EPICS.

The SPEED project - the Segmented Pupil Experiment for Exoplanet Detection - in development at the Lagrange laboratory, aims at gearing up strategies and technologies for high-contrast instrumentation with segmented telescopes. This new instrumental platform offers an ideal environment in which to make progress in the domain of ELTs and/or space-based missions with complex apertures. It combines all the required recipes (phasing optics, wavefront control/shaping, and advanced coronagraphy) to get to very close angular separation imaging. In this paper, we report on the optical design and subsystems advances and we provide a progress overview.

The discovery of thousands of exoplanets is generating increasing interest in the direct imaging and characterization of these planets. Starshade, an external occulter, could fly in formation between a telescope and distant star, blocking out the light from the star, and enabling us to focus on the light of any orbiting planets. Recent technology developments in coordination with system level design, has added much needed detail to define the technology requirements for a science mission that could launch in the 2020’s. This paper addresses the mechanical architecture, the successful efforts to date, the current state of design for the mechanical system, and upcoming technology efforts.

International audience; The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument aims at detecting extremely faint sources (giant extrasolar planets) in the vicinity of bright stars1. Such a challenging goal requires the use of a very-high-order performance Adaptive Optics [AO] system feeding the scientific instruments with a quasi-perfect flat wave front corrected from all the atmospheric turbulence and internal defects. This AO system, called SAXO (Sphere Ao for eXoplanet Observation) is the heart of the instrument, a heart beating 1200 time per second and providing unprecedented image quality for a large ground based telescope at optical/near infrared wavelength. We will present the latest results obtained on-sky, demonstrating its exceptional performance (in terms of correction quality, stability and robustness) and tremendous potentiality for high contrast imaging and more specifically for exoplanet discovery.

Sirius has always attracted a lot of scientific interest, especially after the discovery of a companion white dwarf at the end of the 19th century. Very early on, the existence of a potential third body was put forward to explain some of the observed properties of the system. We present new coronagraphic observations obtained with VLT/SPHERE that explore, for the very first time, the innermost regions of the system down to 0.2" (0.5 AU) from Sirius A. Our observations cover the near-infrared from 0.95 to 2.3 $\mu$m and they offer the best on-sky contrast ever reached at these angular separations. After detailing the steps of our SPHERE/IRDIFS data analysis, we present a robust method to derive detection limits for multi-spectral data from high-contrast imagers and spectrographs. In terms of raw performance, we report contrasts of 14.3 mag at 0.2", ~16.3 mag in the 0.4-1.0" range and down to 19 mag at 3.7". In physical units, our observations are sensitive to giant planets down to 11 $M_{Jup}$ at 0.5 AU, 6-7 $M_{Jup}$ in the 1-2 AU range and ~4 $M_{Jup}$ at 10 AU. Despite the exceptional sensitivity of our observations, we do not report the detection of additional companions around Sirius A. Using a Monte Carlo orbital analysis, we show that we can reject, with about 50% probability, the existence of an 8 $M_{Jup}$ planet orbiting at 1 AU. In addition to the results presented in the paper, we provide our SPHERE/IFS data reduction pipeline at http://people.lam.fr/vigan.arthur/ under the MIT license., Comment: 16 pages, 10 figures, accepted for publication in MNRAS

The Dome C should benefit from an outstanding atmospheric quality during the night due to catabatic wind conditions (wind speed ~ 2 m s -1 , r 0 ~ 0.3 m). From analytical and numerical simulations, we show that these seeing conditions are very advantageous for high-contrast imaging and coronagraphic search of exoplanets in the near-IR with adaptive optics (AO): from the Dome C, the planet SNR is 4 times greater than from Mauna-Kea. For these reasons, the Dome C seems to be the natural site for a Planet-Finder consisting in a 2–8 m (possibly off-axis) monolithic telescope equipped with a fast and extreme AO ( f ~ 1–2 kHz, f ~ cm), a low-aliasing wave-front sensor (WFS), a coronagraph and a speckle-noise subtraction. In these optimal conditions, a 3.6 m and a 8.2 m-telescope can respectively detect a Jupiter-size and an Earth-size planet at 10 pc in 10h in J band. Lastly, a 15–30 m ELT located at the Dome C could perform fast spectral analysis of Earth-like planets for biomarker searching.

The study of extra-solar planets currently motivates a number of large scale observation programs, and also new developments for dedicated instruments. Such programs involve a wide range of observational techniques, from either space-based or ground-based telescopes, including high contrast imaging, photometry, spectroscopy or interferometry. After a brief overview, we discuss here if, how and for which part, the specificities of the Dome C site can significantly contribute to this general observation strategy.

We discuss the properties of extrasolar planets inferred from observations and theoretical models. We show that COROT should be able to usefully constrain the albedos of extrasolar planets with short orbital periods, given levels of stellar variability close to that of the Sun. We sketch possible strategies for observational astrophysical programs using high contrast imaging.

International audience; Direct imaging of exoplanets is very attractive but challenging and specific instruments like Sphere (VLT) or GPI (Gemini) are required to provide contrasts up to 16-17 magnitudes at a fraction of arcsec. To reach higher contrasts and detect fainter exoplanets, more-achromatic coronagraphs and a more-accurate wavefront control are needed. We already demontrated contrasts of ∼ 10 −8 at ∼ 4 λ/D at 635nm using a four quadrant phase mask and a self-coherent camera on our THD bench in laboratory. In this paper, we list the different techniques that were tested on the THD bench in monochromatic and polychromatic lights. Then, we present the upgraded version of the THD bench that includes several deformable mirrors for correcting phase and amplitude simultaneously and obtain a field-of-view covering the complete 360 degrees arouns the star with contrasts down to ∼ 10 −8 − 10 −9 .

The Astrophysics Focused Telescope Assets (AFTA) is one of a pair of space-qualified 2.4 meter diameter telescopes given to NASA. One plan is to use the telescope for WFIRST with a coronagraph as a secondary instrument for high contrast imaging of exoplanets and disks. Because the system is obscured by a secondary mirror and spiders, it is not the optimal unobscured configuration to which most of current proposed space coronagraphs have been designed. In the later half of 2013 a study was undertaken to evaluate coronagraphs designed specifically for the AFTA telescope. As part of this process, end-to-end numerical modeling was performed with a realistically aberrated system to determine the contrast limits of each technique. Reported here are the simulation procedures and a summary of results for four coronagraphs (hybrid Lyot, shaped pupil, vector vortex, and PIAA complex mask) evaluated for the technology downselect.

To directly image exoplanets and faint circumstellar disks, the noisy stellar halo must be suppressed to a high level. To achieve this feat, the angular differential imaging observing technique and the least-squares Locally Optimized Combination of Images (LOCI) algorithm have now become the standard in single band direct imaging observations and data reduction. With the development and commissioning of new high-order high-contrast adaptive optics equipped with integral field units, the image subtraction algorithm needs to be modified to allow the optimal use of polychromatic images, field-rotated images and archival data. A new algorithm, TLOCI (for Template LOCI), is designed to achieve this task by maximizing a companion signal-to-noise ratio instead of simply minimizing the noise as in the original LOCI algorithm. The TLOCI technique uses an input spectrum and template Point Spread Functions (PSFs, generated from unocculted and unsaturated stellar images) to optimize the reference image least-squares coefficients to minimize the planet self-subtraction, thus maximizing its throughput per wavelength, while simultaneously providing a maximum suppression of the speckle noise. The new algorithm has been developed using on-sky GPI data and has achieved impressive contrast. This paper presents the TLOCI algorithm, on-sky performance, and will discuss the challenges in recovering the planet spectrum with high fidelity., Adaptive Optics Systems IV, June 22-27, 2014, Series: Proceedings of SPIE; no. 9148

We present in this paper an overview of the high contrast imaging modes of the wide-field imager MICADO. MICADO is a near-IR camera for the European Extremely Large Telescope (E-ELT), featuring a wide field (75”), spectroscopic and coronagraphic capabilities. It has been chosen by ESO as one of the two first-light instruments. MICADO will be optimized for the multi-conjugate adaptive optics module MAORY and will also work in SCAO mode. This SCAO mode will provide MICADO with a high-level, on-axis correction, making use of the M4 adaptive mirror in the telescope. After presenting the scientific interest for high contrast imaging modes in MICADO, we describe the technical choices we are studying. We present the hypotheses chosen for our simulation tools and contrast as well as planet detection performance derived from this tool.

The Gemini Planet Imager (GPI) is a next-generation, facility instrument currently being commissioned at the Gemini South observatory. GPI combines an extreme adaptive optics system and integral field spectrograph (IFS) with an apodized-pupil Lyot coronagraph (APLC) producing an unprecedented capability for directly imaging and spectroscopically characterizing extrasolar planets. GPI's operating goal of 10-7 contrast requires very precise alignments between the various elements of the coronagraph (two pupil masks and one focal plane mask) and active control of the beam path throughout the instrument. Here, we describe the techniques used to automatically align GPI and maintain the alignment throughout the course of science observations. We discuss the particular challenges of maintaining precision alignments on a Cassegrain mounted instrument and strategies that we have developed that allow GPI to achieve high contrast even in poor seeing conditions., Ground-Based and Airborne Instrumentation for Astronomy V, June 22-26, 2014, Series: Proceedings of SPIE; no. 9147

We present the results of both laboratory and on sky astrometric characterization of the Gemini Planet Imager (GPI). This characterization includes measurement of the pixel scale∗ of the integral field spectrograph (IFS), the position of the detector with respect to north, and optical distortion. Two of these three quantities (pixel scale and distortion) were measured in the laboratory using two transparent grids of spots, one with a square pattern and the other with a random pattern. The pixel scale in the laboratory was also estimate using small movements of the artificial star unit (ASU) in the GPI adaptive optics system. On sky, the pixel scale and the north angle are determined using a number of known binary or multiple systems and Solar System objects, a subsample of which had concurrent measurements at Keck Observatory. Our current estimate of the GPI pixel scale is 14.14 ± 0.01 millarcseconds/pixel, and the north angle is -1.00 ± 0.03°. Distortion is shown to be small, with an average positional residual of 0.26 pixels over the field of view, and is corrected using a 5th order polynomial. We also present results from Monte Carlo simulations of the GPI Exoplanet Survey (GPIES) assuming GPI achieves ∼1 milliarcsecond relative astrometric precision. We find that with this precision, we will be able to constrain the eccentricities of all detected planets, and possibly determine the underlying eccentricity distribution of widely separated Jovians., Ground-Based and Airborne Instrumentation for Astronomy V, June 22-26, 2014, Series: Proceedings of SPIE; no. 9147

The Gemini Planet Imager (GPI) has as its science instrument an infrared integral field spectrograph/polarimeter (IFS). Integral field spectrographs are scientificially powerful but require sophisticated data reduction systems. For GPI to achieve its scientific goals of exoplanet and disk characterization, IFS data must be reconstructed into high quality astrometrically and photometrically accurate datacubes in both spectral and polarization modes, via flexible software that is usable by the broad Gemini community. The data reduction pipeline developed by the GPI instrument team to meet these needs is now publicly available following GPI's commissioning. This paper, the first of a series, provides a broad overview of GPI data reduction, summarizes key steps, and presents the overall software framework and implementation. Subsequent papers describe in more detail the algorithms necessary for calibrating GPI data. The GPI data reduction pipeline is open source, available from planetimager.org, and will continue to be enhanced throughout the life of the instrument. It implements an extensive suite of task primitives that can be assembled into reduction recipes to produce calibrated datasets ready for scientific analysis. Angular, spectral, and polarimetric differential imaging are supported. Graphical tools automate the production and editing of recipes, an integrated calibration database manages reference files, and an interactive data viewer customized for high contrast imaging allows for exploration and manipulation of data., Ground-Based and Airborne Instrumentation for Astronomy V, June 22-26, 2014, Series: Proceedings of SPIE; no. 9147

The Gemini Planet Imager (GPI) entered on-sky commissioning and had its first-light at the Gemini South (GS) telescope in November 2013. GPI is an extreme adaptive optics (XAO), high-contrast imager and integral-field spectrograph dedicated to the direct detection of hot exo-planets down to a Jupiter mass. The performance of the apodized pupil Lyot coronagraph depends critically upon the residual wavefront error (design goal of 60nmRMS with, Adaptive Optics Systems IV, June 22-27, 2014, Series: Proceedings of SPIE; no. 9148

In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its $\sim$130-night campaign from the Large Binocular Telescope (LBT) atop Mt Graham, Arizona. This survey benefits from the many technological achievements of the LBT, including two 8.4-meter mirrors on a single fixed mount, dual adaptive secondary mirrors for high Strehl performance, and a cold beam combiner to dramatically reduce the telescope's overall background emissivity. LEECH neatly complements other high-contrast planet imaging efforts by observing stars at L' (3.8 $\mu$m), as opposed to the shorter wavelength near-infrared bands (1-2.4 $\mu$m) of other surveys. This portion of the spectrum offers deep mass sensitivity, especially around nearby adolescent ($\sim$0.1-1 Gyr) stars. LEECH's contrast is competitive with other extreme adaptive optics systems, while providing an alternative survey strategy. Additionally, LEECH is characterizing known exoplanetary systems with observations from 3-5$\mu$m in preparation for JWST., Comment: 12 pages, 5 figures. Proceedings of the SPIE, 9148-20

The Gemini Planet Imager (GPI) combines extreme adaptive optics, an integral field spectrograph, and a high performance coronagraph to directly image extrasolar planets in the near-infrared. Because the coronagraph blocks most of the light from the star, it prevents the properties of the host star from being measured directly. Instead, satellite spots, which are created by diffraction from a square grid in the pupil plane, can be used to locate the star and extract its spectrum. We describe the techniques implemented into the GPI Data Reduction Pipeline to measure the properties of the satellite spots and discuss the precision of the reconstructed astrometry and spectrophotometry of the occulted star. We find the astrometric precision of the satellite spots in an H-band datacube to be 0.05 pixels and is best when individual satellite spots have a signal to noise ratio (SNR) of > 20. In regards to satellite spot spectrophotometry, we find that the total flux from the satellite spots is stable to ∼7% and scales linearly with central star brightness and that the shape of the satellite spot spectrum varies on the 2% level., Ground-Based and Airborne Instrumentation for Astronomy V, June 22-26, 2014, Series: Proceedings of SPIE; no. 9147

We present and compare experimental results in high contrast imaging representing the state of the art in coronagraph and starshade technology. These experiments have been undertaken with the goal of demonstrating the capability of detecting Earth-like planets around nearby Sun-like stars. The contrast of an Earth seen in reflected light around a Sun-like star would be about 1.2 x 10(exp -10). Several of the current candidate technologies now yield raw contrasts of 1.0 x 10(exp -9) or better, and so should enable the detection of Earths, assuming a gain in sensitivity in post-processing of a factor of 10. We present results of coronagraph and starshade experiments conducted at visible and infrared wavelengths. Cross-sections of dark fields are directly compared as a function of field angle and bandwidth. The strength and differences of the techniques are compared.

The vortex coronagraph has already enabled high-contrast observations very close to bright stars on large ground-based telescopes, and it also has great potential for use on coronagraphic space missions aimed at exoplanet detection and characterization. As such, demonstrations of vortex coronagraph performance have recently been carried out in JPL’s High Contrast Imaging Testbed. Some of our recent results are presented here, including the suppression of a monochromatic, single-polarization point-source to below the 10^(-9) level over a dark hole covering both the 2-7 λ/D and 3-8 λ/D regions, as well as the suppression of a 10% band of white-light to approximately the 10^(-8) level over a 3-8 λ/D dark hole.

Direct imaging and low-resolution spectroscopy of extrasolar planets are exciting but challenging scientific applications of coronagraphy. While the angular separation is well within the reach of actual telescope in the near IR or visible, the planet-star contrast (from 10-6 to 10-10) requires wavefront quality and stability hard to reach even with a well-polished space telescope. Several solutions have been proposed to tackle the speckle noise introduced by the residual optical defects. While some concepts rely only on active wavefront correction using deformable mirror, other techniques are based on post-processing and subtract a reference image recorded sometimes simultaneously with the science image. One interesting solution is to choose a concept that allows both active correction and post-processing of high contrast coronagraphic images. This is the case of the Self Coherent Camera (SCC), which has been proposed for the project of space coronagraph SPICES and for the ground-based planet finder EPICS studied for the European Extremely Large Telescope. After recalling the SCC principle, we present both monochromatic and modest bandwidth (2%) experimental results of Dark Hole in the focal plane using a SCC. Example of a post-processing result with SCC is also given to emphasize the interest of combining it with active correction. © 2012 SPIE., Ground-Based and Airborne Instrumentation for Astronomy IV, July 1-6, 2012, Amsterdam, The Netherlands, Series: Proceedings of SPIE; no. 8446

The paper motivates the science requirements for high-contrast imaging illustrated by actual observation results. After an introduction to the high-contrast-imaging problem composed of extreme adaptive optics, coronagraphy, wave-front control an post-processing, the state-of-the-art will be reviewed putting emphasis on existing instruments and those that are near completion: LBT-FLAO, Magellan Mag AO, Palomar P3K / P1640, Subaru SCExAO, Gemini GPI, and VLT SPHERE.

Several small space coronagraphs have been proposed to characterize cold exoplanets in reected light. Studies have mainly focused on technical feasibility because of the huge star/planet ux ratio to achieve in the close-in stellar environment (108-1010 at 0.2). However, the main interest of such instruments, the analysis of planet properties, has remained highly unexplored so far. We performed numerical simulations to assess the ability of a small space coronagraph to retrieve spectra of mature Jupiters, Neptunes and super-Earths under realistic assumptions. We describe our assumptions: exoplanetary atmosphere models, instrument numerical simulation and observing conditions. Then, we define a criterion and use it to determine the required exposure times to measure several planet parameters from their spectra (separation, metallicity, cloud and surface coverages) for particular cases. Finally, we attempt to define a parameter space of the potential targets. In the case of a solar-type star, we show that a small coronagraph can characterize the spectral properties of a 2-AU Jupiter up to 10 pc and the cloud and surface coverage of super-Earths in the habitable zone for a few stars within 4{5 pc. Potentially, SPICES could perform analysis of a hypothetical Earth-size planet around α Cen A and B., Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, July 1-6, 2012, Amsterdam, Netherlands, Series: Proceedings of SPIE

The Fine Guidance Sensor (FGS) is one of the four science instruments on board the JamesWebb Space Telescope (JWST). FGS features two modules: an infrared camera dedicated to fine guiding of the observatory and a science camera module, the Near-Infrared Imager and Slitless Spectrograph (NIRISS) covering the wavelength range between 0.7 and 5.0 μm with a field of view of 2.2'×2.2'. NIRISS has four observing modes: 1) broadband imaging featuring seven of the eight NIRCam broadband filters, 2) wide-field slitless spectroscopy at a resolving power of ̃150 between 1 and 2.5 μm, 3) single-object cross-dispersed slitless spectroscopy enabling simultaneous wavelength coverage between 0.7 and 2.5 μm at R ̃ 660, a mode optimized for transit spectroscopy of relatively bright (J > 7) stars and, 4) sparse aperture interferometric imaging between 3.8 and 4.8 μm enabling high- contrast (̃ 10-4) imaging of M < 8 point sources at angular separations between 70 and 500 milliarcsec. This paper presents an overview of the FGS/NIRISS design with a focus on the scientific capabilities and performance offered by NIRISS. © 2012 SPIE., Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, July 1-6, 2012, Amsterdam, The Netherlands, Series: Proceedings of SPIE; no. 8442

Small-angle coronagraphy is technically and scientifically appealing because it enables the use of smaller telescopes, allows covering wider wavelength ranges, and potentially increases the yield and completeness of circumstellar environment - exoplanets and disks - detection and characterization campaigns. However, opening up this new parameter space is challenging. Here we will review the four posts of high contrast imaging and their intricate interactions at very small angles (within the first 4 resolution elements from the star). The four posts are: choice of coronagraph, optimized wavefront control, observing strategy, and post-processing methods. After detailing each of the four foundations, we will present the lessons learned from the 10+ years of operations of zeroth and first-generation adaptive optics systems. We will then tentatively show how informative the current integration of second-generation adaptive optics system is, and which lessons can already be drawn from this fresh experience. Then, we will review the current state of the art, by presenting world record contrasts obtained in the framework of technological demonstrations for space-based exoplanet imaging and characterization mission concepts. Finally, we will conclude by emphasizing the importance of the cross-breeding between techniques developed for both ground-based and space-based projects, which is relevant for future high contrast imaging instruments and facilities in space or on the ground., Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, July 1-6, 2012, Amsterdam, Netherlands, Series: Proceedings of SPIE

The study of the physico-chemical properties of wide-separated exoplanets (> 1 AU) is a major goal of highcontrast imaging techniques. SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a project of space coronagraph dedicated to the spectro-polarimetric analysis of gas and ice giant planets, super-Earths and circumstellar disks in visible light at a spectral resolution of about 40. After recalling the science cases of the mission, we describe the optical design and the critical subsystems of the instrument. We then discuss the SPICES performance that we derived from numerical simulations., Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave, July 1-6, 2012, Amsterdam, Netherlands, Series: Proceedings of SPIE

The Starshade is an external occulter being developed for a future exoplanet imaging and characterization mission. The large, petal-shaped screen efficiently blocks starlight (to better than 1 part in 1010) by using precisely-controlled edges to suppress diffraction and prevent the formation of Arago's spot. A conventional telescope, operating in the shadow of the starshade, then has an unobstructed view of any companion terrestrial planets; these observations require a 4m or larger telescope in order to provide adequate sensitivity and resolution. The starshade itself must be tens of meters across and the starshade structure must therefore be deployable to fit within existing launch vehicles. As a point of departure, we present the New Worlds Observer mission concept, which uses a 62m tip-to-tip starshade with a 4m telescope, separated by 80,000 km. Our fundamental starshade design philosophy includes using high-heritage, high-TRL components and passive control of the starshade's precision structure. This paper outlines the driving requirements for the starshade payload and our design elements that meet these requirements. We have developed a roadmap and a technology maturation plan for the starshade payload. We discuss pathfinder units we have build for this and other components of the starshade, and the current state of the art towards meeting starshade tolerance requirements. We present thermal and dynamics analyses of our starshade design and show that the design is within the error budget. We will motivate the path forward leading to a subscale demonstration of the starshade and show that this is a useful part of an overall starshade technology development program.

Direct imaging and spectroscopy can advance our understanding of planet formation and migration through the detection and characterization of extrasolar planets on wide orbits. Accurate photometry and astrometry of detected companions are of crucial importance to derive the planet physical properties.We present an extension of the Locally optimized combination of images (LOCI) method to measure the highest-fidelity photometry as well as accurate astrometry of detected companions. This algorithm is also generalized to Integral-Field Spectrograph (IFS) data processing, giving advantages of a simultaneous angular and spectral differential imaging reduction, retrieving high-fidelity spectra from PSF-subtracted cubes. © 2012 SPIE., Adaptive Optics Systems III, July 1-6, 2012, Amsterdam, the Netherlands, Series: Proceedings of SPIE; no. 8447