High-contrast Differential Image Processing for Extrasolar Planet Detection

High-contrast Differential Image Processing for Extrasolar Planet Detection
Author: Alberto Cornia
Publisher:
Total Pages: 142
Release: 2010
Genre:
ISBN:
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This thesis is dedicated to the ground-based exoplanet detection and it has been developed in the context of the SPHERE project of ESO; the installation of this instrument is planned for 2011 on the VLT. To directly deleted exoplanets, SPHERE will combine an extreme adaptive optics System, a coronagraph and imagery at two or more wavelengths. To distinguish between the planet signal and the speckles due to the aberrations, we need to elaborate a sophisticated method of data processing which exploits also the temporal information. I developed a method, called ANDROMEDA, which allows to detect exoplanets and to estimate their flux. It uses image differences which aim at eliminating the effects of unknown quasi-static aberrations and of the variability of the quality oi adaptive optics correction. The algorithm couples images taken at different instants which present a field rotation between them, and possibly images taken at two different wavelengths. I showed that ANDROMEDA meets the requirements of SPHERE for the detections of planets at a contrast o 106 at a separation of 0.5" from the star, and it can even do better, reaching a separation of 0.2" for the same contrast. Then I carried out a parametric study of the method to analyze the robustness of the flux estimation towards different sources of error. Finally, I tested ANDROMEDA on experimental data provided by the NACO instrument; this analysis allowed us to understand how to deal with typical problems posed by data reduction and instrumental artifacts.

Exploring Planetary System Evolution Through High-Contrast Imaging

Exploring Planetary System Evolution Through High-Contrast Imaging
Author: Thomas Matthew Esposito
Publisher:
Total Pages: 143
Release: 2015
Genre:
ISBN:
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High-contrast imaging of circumstellar debris disks and exoplanets provides unique information about planetary system evolution. Several hundred nearby main-sequence stars are known to host debris disks: reservoirs of rock and ice that are thought to be coeval with planet formation. My dissertation research focused on detecting and characterizing such disks to gain new insight into circumstellar environments during the epoch of planet assembly. To view these systems on spatial scales down to a few astronomical units, I used near-infrared angular differential imaging data from the Keck NIRC2 and Gemini Planet Imager instruments. Detection of relatively faint disks and planets in these data is enhanced by image-processing algorithms that suppress the stellar signal, however, they also bias the brightnesses of these objects. I developed a new technique to forward-model and correct for this bias, thus allowing more accurate analysis of disk and planet properties. Applying this technique to scattered-light imaging of the HD 32297 debris disk, I used photometric and morphological measurements to infer physical characteristics of the disk and its constituent grains. I also investigated the HD 61005 debris disk and the role that an eccentric, inclined planet could play in shaping its unusual morphology. To expand the small samples of resolved disks and directly-imaged planets, I conducted a coronagraphic survey of 24 nearby stars, the preliminary results of which are reported herein. Concluding on the same theme of high-angular resolution imaging, my final project comprised tasks translating science requirements into design specifications for an upgraded Keck OSIRIS imager.

Probing Other Solar Systems with Current and Future Adaptive Optics

Probing Other Solar Systems with Current and Future Adaptive Optics
Author:
Publisher:
Total Pages: 18
Release: 2008
Genre:
ISBN:
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Over the past decade, the study of extrasolar planets through indirect techniques--primarily Doppler measurements--has revolutionized our understanding of other solar systems. The next major step in this field will be the direct detection and characterization, via imaging and spectroscopy, of the planets themselves. To achieve this, we must separate the light from the faint planet from the extensive glare of its parent star. We pursued this goal using the current generation of adaptive optics (AO) systems on large ground-based telescopes, using infrared imaging to search for the thermal emission from young planets and developing image processing techniques to distinguish planets from telescope-induced artifacts. Our new Angular Differential Imaging (ADI) technique, which uses the sidereal rotation of the Earth and telescope, is now standard for ground-based high-contrast imaging. Although no young planets were found in our surveys, we placed the strongest limits yet on giant planets in wide orbits (>30 AU) around young stars and characterized planetary companion candidates. The imaging of planetary companions on solar-system-like scales (5-30 AU) will require a new generation of advanced AO systems that are an order of magnitude more powerful than the LLNL-built Keck AO system. We worked to develop and test the key technologies needed for these systems, including a spatially-filtered wavefront sensor, efficient and accurate wavefront reconstruction algorithms, and precision AO wavefront control at the sub-nm level. LLNL has now been selected by the Gemini Observatory to lead the construction of the Gemini Planet Imager, a $24M instrument that will be the most advanced AO system in the world.

Exoplanet Science Strategy

Exoplanet Science Strategy
Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
Total Pages: 187
Release: 2019-01-17
Genre: Science
ISBN: 030947941X
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The past decade has delivered remarkable discoveries in the study of exoplanets. Hand-in-hand with these advances, a theoretical understanding of the myriad of processes that dictate the formation and evolution of planets has matured, spurred on by the avalanche of unexpected discoveries. Appreciation of the factors that make a planet hospitable to life has grown in sophistication, as has understanding of the context for biosignatures, the remotely detectable aspects of a planet's atmosphere or surface that reveal the presence of life. Exoplanet Science Strategy highlights strategic priorities for large, coordinated efforts that will support the scientific goals of the broad exoplanet science community. This report outlines a strategic plan that will answer lingering questions through a combination of large, ambitious community-supported efforts and support for diverse, creative, community-driven investigator research.

Astronomical Optics

Astronomical Optics
Author: Daniel J. Schroeder
Publisher: Elsevier
Total Pages: 367
Release: 2012-12-02
Genre: Science
ISBN: 032313856X
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Written by a recognized expert in the field, this clearly presented, well-illustrated book provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today. Written by a recognized expert in the field Provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today

Nulling Interferometers for Space-based High-Contrast Visible Imaging and Measurement of Exoplanetary Environments

Nulling Interferometers for Space-based High-Contrast Visible Imaging and Measurement of Exoplanetary Environments
Author: Brian Hicks
Publisher: Springer Science & Business Media
Total Pages: 139
Release: 2013-10-17
Genre: Technology & Engineering
ISBN: 1461482119
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High-contrast astronomical imaging has progressed significantly in the past decade. Many of these techniques have been laboratory demonstrated to perform at contrast levels adequate for the detection of Solar System-like planets and dust around nearby stars. None of them, however, have been demonstrated in space. The state of the art in high-contrast imaging systems that have been built for space-based observation, the environment best suited for spectroscopic study of exo-Earths, is the nulling interferometer that was flown on the Planetary Imaging Concept Testbed Using a Rocket Experiment (PICTURE). The PICTURE nulling interferometer, built from multiple optical elements, relies on the incorporation of additional dispersive components in order to deliver the broadband performance preferred for faint object imaging. These elements add to the cost, complexity, and misalignment risk of the instrument. The Monolithic Achromatic Nulling Interference Coronagraph (MANIC) Brian Hicks describe in this thesis the first optic of its kind. He has taken the multiple optical element concept described in earlier works from theory to a flyable monolithic optic. Brian has advanced the state of the art in nulling interferometers by improving optical stability and robustness. Following application of the fabrication method described in this work, the design of MANIC also allows for broader band performance at higher contrast than that achieved with the PICTURE nulling interferometer.

New Worlds, New Horizons in Astronomy and Astrophysics

New Worlds, New Horizons in Astronomy and Astrophysics
Author: National Research Council
Publisher: National Academies Press
Total Pages: 324
Release: 2011-02-04
Genre: Science
ISBN: 0309157994
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Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.