References of "Labadie, L"      in Complete repository Arts & humanities   Archaeology   Art & art history   Classical & oriental studies   History   Languages & linguistics   Literature   Performing arts   Philosophy & ethics   Religion & theology   Multidisciplinary, general & others Business & economic sciences   Accounting & auditing   Production, distribution & supply chain management   Finance   General management & organizational theory   Human resources management   Management information systems   Marketing   Strategy & innovation   Quantitative methods in economics & management   General economics & history of economic thought   International economics   Macroeconomics & monetary economics   Microeconomics   Economic systems & public economics   Social economics   Special economic topics (health, labor, transportation…)   Multidisciplinary, general & others Engineering, computing & technology   Aerospace & aeronautics engineering   Architecture   Chemical engineering   Civil engineering   Computer science   Electrical & electronics engineering   Energy   Geological, petroleum & mining engineering   Materials science & engineering   Mechanical engineering   Multidisciplinary, general & others Human health sciences   Alternative medicine   Anesthesia & intensive care   Cardiovascular & respiratory systems   Dentistry & oral medicine   Dermatology   Endocrinology, metabolism & nutrition   Forensic medicine   Gastroenterology & hepatology   General & internal medicine   Geriatrics   Hematology   Immunology & infectious disease   Laboratory medicine & medical technology   Neurology   Oncology   Ophthalmology   Orthopedics, rehabilitation & sports medicine   Otolaryngology   Pediatrics   Pharmacy, pharmacology & toxicology   Psychiatry   Public health, health care sciences & services   Radiology, nuclear medicine & imaging   Reproductive medicine (gynecology, andrology, obstetrics)   Rheumatology   Surgery   Urology & nephrology   Multidisciplinary, general & others Law, criminology & political science   Civil law   Criminal law & procedure   Criminology   Economic & commercial law   European & international law   Judicial law   Metalaw, Roman law, history of law & comparative law   Political science, public administration & international relations   Public law   Social law   Tax law   Multidisciplinary, general & others Life sciences   Agriculture & agronomy   Anatomy (cytology, histology, embryology...) & physiology   Animal production & animal husbandry   Aquatic sciences & oceanology   Biochemistry, biophysics & molecular biology   Biotechnology   Entomology & pest control   Environmental sciences & ecology   Food science   Genetics & genetic processes   Microbiology   Phytobiology (plant sciences, forestry, mycology...)   Veterinary medicine & animal health   Zoology   Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences   Chemistry   Earth sciences & physical geography   Mathematics   Physics   Space science, astronomy & astrophysics   Multidisciplinary, general & others Social & behavioral sciences, psychology   Animal psychology, ethology & psychobiology   Anthropology   Communication & mass media   Education & instruction   Human geography & demography   Library & information sciences   Neurosciences & behavior   Regional & inter-regional studies   Social work & social policy   Sociology & social sciences   Social, industrial & organizational psychology   Theoretical & cognitive psychology   Treatment & clinical psychology   Multidisciplinary, general & others     Showing results 1 to 10 of 10 1 Space-based infrared interferometry to study exoplanetary atmospheresDefrere, Denis ; Léger, A.; Absil, Olivier et alin Experimental Astronomy: Astrophysical Instrumentation and Methods (in press), 1801The quest for other habitable worlds and the search for life among them are major goals of modern astronomy. One way to make progress towards these goals is to obtain high-quality spectra of a large ... [more ▼]The quest for other habitable worlds and the search for life among them are major goals of modern astronomy. One way to make progress towards these goals is to obtain high-quality spectra of a large number of exoplanets over a broad range of wavelengths. While concepts currently investigated in the United States are focused on visible/NIR wavelengths, where the planets are probed in reflected light, a compelling alternative to characterize planetary atmospheres is the mid-infrared waveband (5-20um). Indeed, mid-infrared observations provide key information on the presence of an atmosphere, the surface conditions (e.g., temperature, pressure, habitability), and the atmospheric composition in important species such as H2O, CO2, O3, CH4, and N2O. This information is essential to investigate the potential habitability of exoplanets and to make progress towards the search for life in the universe. Obtaining high-quality mid-infrared spectra of exoplanets from the ground is however extremely challenging due to the overwhelming brightness and turbulence of Earth's atmosphere. In this paper, we present a concept of space-based mid-infrared interferometer that can tackle this observing challenge and discuss the main technological developments required to launch such a sophisticated instrument. [less ▲]Detailed reference viewed: 45 (1 ULiège) The path towards high-contrast imaging with the VLTI: the Hi-5 projectDefrere, Denis ; Absil, Olivier ; Berger, J.-P. et alin Experimental Astronomy: Astrophysical Instrumentation and Methods (in press), 1801The development of high-contrast capabilities has long been recognized as one of the top priorities for the VLTI. As of today, the VLTI routinely achieves contrasts of a few 10$^{-3}$ in the near-infrared ... [more ▼]The development of high-contrast capabilities has long been recognized as one of the top priorities for the VLTI. As of today, the VLTI routinely achieves contrasts of a few 10$^{-3}$ in the near-infrared with PIONIER (H band) and GRAVITY (K band). Nulling interferometers in the northern hemisphere and non-redundant aperture masking experiments have, however, demonstrated that contrasts of at least a few 10$^{-4}$ are within reach using specific beam combination and data acquisition techniques. In this paper, we explore the possibility to reach similar or higher contrasts on the VLTI. After reviewing the state-of-the-art in high-contrast infrared interferometry, we discuss key features that made the success of other high-contrast interferometric instruments (e.g., integrated optics, nulling, closure phase, and statistical data reduction) and address possible avenues to improve the contrast of the VLTI by at least one order of magnitude. In particular, we discuss the possibility to use integrated optics, proven in the near-infrared, in the thermal near-infrared (L and M bands, 3-5 $\mu$m), a sweet spot to image and characterize young extra-solar planetary systems. Finally, we address the science cases of a high-contrast VLTI imaging instrument and focus particularly on exoplanet science (young exoplanets, planet formation, and exozodiacal disks), stellar physics (fundamental parameters and multiplicity), and extragalactic astrophysics (active galactic nuclei and fundamental constants). Synergies and scientific preparation for other potential future instruments such as the Planet Formation Imager are also briefly discussed. [less ▲]Detailed reference viewed: 22 (10 ULiège) Planet Formation Imager (PFI): Science vision and key requirementsKraus, S.; Monnier, J. D.; Ireland, M. J. et alin Proceedings of SPIE (2016)The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that ... [more ▼]The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that a breakthrough in angular resolution imaging capabilities is required in order to unravel the processes involved in planet formation. PFI will be optimised to provide a complete census of the protoplanet population at all stellocentric radii and over the age range from 0.1 to ∼100 Myr. Within this age period, planetary systems undergo dramatic changes and the final architecture of planetary systems is determined. Our goal is to study the planetary birth on the natural spatial scale where the material is assembled, which is the "Hill Sphere" of the forming planet, and to characterise the protoplanetary cores by measuring their masses and physical properties. Our science working group has investigated the observational characteristics of these young protoplanets as well as the migration mechanisms that might alter the system architecture. We simulated the imprints that the planets leave in the disk and study how PFI could revolutionise areas ranging from exoplanet to extragalactic science. In this contribution we outline the key science drivers of PFI and discuss the requirements that will guide the technology choices, the site selection, and potential science/technology tradeoffs. © 2016 SPIE. [less ▲]Detailed reference viewed: 24 (1 ULiège) Planet Formation Imager (PFI): Introduction and technical considerationsMonnier, J. D.; Kraus, S.; Buscher, D. et alin Proceedings of SPIE - The International Society for Optical Engineering (2014), 9146Complex non-linear and dynamic processes lie at the heart of the planet formation process. Through numerical simulation and basic observational constraints, the basics of planet formation are now coming ... [more ▼]Complex non-linear and dynamic processes lie at the heart of the planet formation process. Through numerical simulation and basic observational constraints, the basics of planet formation are now coming into focus. High resolution imaging at a range of wavelengths will give us a glimpse into the past of our own solar system and enable a robust theoretical framework for predicting planetary system architectures around a range of stars surrounded by disks with a diversity of initial conditions. Only long-baseline interferometry can provide the needed angular resolution and wavelength coverage to reach these goals and from here we launch our planning efforts. The aim of the "Planet Formation Imager" (PFI) project is to develop the roadmap for the construction of a new near-/mid-infrared interferometric facility that will be optimized to unmask all the major stages of planet formation, from initial dust coagulation, gap formation, evolution of transition disks, mass accretion onto planetary embryos, and eventual disk dispersal. PFI will be able to detect the emission of the cooling, newlyformed planets themselves over the first 100 Myrs, opening up both spectral investigations and also providing a vibrant look into the early dynamical histories of planetary architectures. Here we introduce the Planet Formation Imager (PFI) Project (www.planetformationimager.org) and give initial thoughts on possible facility architectures and technical advances that will be needed to meet the challenging top-level science requirements. © 2014 SPIE. [less ▲]Detailed reference viewed: 7 (2 ULiège) The science case for the Planet Formation Imager (PFI)Kraus, S.; Monnier, J.; Harries, T. et alin Proceedings of SPIE - The International Society for Optical Engineering (2014), 9146Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar ... [more ▼]Among the most fascinating and hotly-debated areas in contemporary astrophysics are the means by which planetary systems are assembled from the large rotating disks of gas and dust which attend a stellar birth. Although important work has already been, and is still being done both in theory and observation, a full understanding of the physics of planet formation can only be achieved by opening observational windows able to directly witness the process in action. The key requirement is then to probe planet-forming systems at the natural spatial scales over which material is being assembled. By definition, this is the so-called Hill Sphere which delineates the region of influence of a gravitating body within its surrounding environment. The Planet Formation Imager project (PFI; http://www.planetformationimager.org) has crystallized around this challenging goal: to deliver resolved images of Hill-Sphere-sized structures within candidate planethosting disks in the nearest star-forming regions. In this contribution we outline the primary science case of PFI. For this purpose, we briefly review our knowledge about the planet-formation process and discuss recent observational results that have been obtained on the class of transition disks. Spectro-photometric and multi-wavelength interferometric studies of these systems revealed the presence of extended gaps and complex density inhomogeneities that might be triggered by orbiting planets. We present detailed 3-D radiation-hydrodynamic simulations of disks with single and multiple embedded planets, from which we compute synthetic images at near-infrared, mid-infrared, far-infrared, and sub-millimeter wavelengths, enabling a direct comparison of the signatures that are detectable with PFI and complementary facilities such as ALMA. From these simulations, we derive some preliminary specifications that will guide the array design and technology roadmap of the facility. © 2014 SPIE. [less ▲]Detailed reference viewed: 19 (1 ULiège) Technology for a Mid-IR Flagship Mission to Characterize Earth-like ExoplanetsLawson, P. R.; Absil, Olivier ; Akeson, R. L. et alE-print/Working paper (2009)The exploration of Earth-like exoplanets will be enabled at mid-infrared wavelengths through technology and engineering advances in nulling interferometry and precision formation flying. Nulling ... [more ▼]The exploration of Earth-like exoplanets will be enabled at mid-infrared wavelengths through technology and engineering advances in nulling interferometry and precision formation flying. Nulling interferometry provides the dynamic range needed for the detection of biomarkers. Formation flying provides the angular resolution required in the mid-infrared to separately distinguish the spectra of planets in multi-planet systems. The flight performance requirements for nulling have been met and must now be validated in a flight-like environment. Formation-flying algorithms have been demonstrated in the lab and must now be validated in space. Our proposed technology program is described. [less ▲]Detailed reference viewed: 29 (4 ULiège) Darwin-A Mission to Detect and Search for Life on Extrasolar PlanetsCockell, C. S.; Léger, A.; Fridlund, M. et alin Astrobiology (2009), 9(1)The discovery of extrasolar planets is one of the greatest achievements of modern astronomy. The detection of planets that vary widely in mass demonstrates that extrasolar planets of low mass exist. In ... [more ▼]The discovery of extrasolar planets is one of the greatest achievements of modern astronomy. The detection of planets that vary widely in mass demonstrates that extrasolar planets of low mass exist. In this paper, we describe a mission, called Darwin, whose primary goal is the search for, and characterization of, terrestrial extrasolar planets and the search for life. Accomplishing the mission objectives will require collaborative science across disciplines, including astrophysics, planetary sciences, chemistry, and microbiology. Darwin is designed to detect rocky planets similar to Earth and perform spectroscopic analysis at mid-infrared wavelengths (6-20 mum), where an advantageous contrast ratio between star and planet occurs. The baseline mission is projected to last 5 years and consists of approximately 200 individual target stars. Among these, 25-50 planetary systems can be studied spectroscopically, which will include the search for gases such as CO[SUB]2[/SUB], H[SUB]2[/SUB]O, CH[SUB]4[/SUB], and O[SUB]3[/SUB]. Many of the key technologies required for the construction of Darwin have already been demonstrated, and the remainder are estimated to be mature in the near future. Darwin is a mission that will ignite intense interest in both the research community and the wider public. [less ▲]Detailed reference viewed: 194 (18 ULiège) The Darwin Ground-based European Nulling Interferometry ExperimentGondoin, P.; Absil, Olivier ; Fridlund, M. et alin Lacoste, H. (Ed.) GENIE - DARWIN Workshop - Hunting for Planets (2003, March 01)Darwin is one of the most challenging space pro jects ever considered by the European Space Agency (ESA). Its principal ob jectives are to detect Earth-like planets around nearby stars and to characterise ... [more ▼]Darwin is one of the most challenging space pro jects ever considered by the European Space Agency (ESA). Its principal ob jectives are to detect Earth-like planets around nearby stars and to characterise their atmospheres. Darwin is conceived as a space nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the o -axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The present paper will describe the ob jectives and the status of the project. [less ▲]Detailed reference viewed: 4 (0 ULiège) Darwin ground-based European nulling interferometer experiment (GENIE)Gondoin, Philippe; Absil, Olivier ; Fridlund, C V Malcolm et alin Traub, Wesley (Ed.) Interferometry for Optical Astronomy II (2003, February 01)Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterize ... [more ▼]Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterize their atmospheres. Darwin is conceived as a space "nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the off-axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The present paper will describe the objectives and the status of the project. [less ▲]Detailed reference viewed: 53 (2 ULiège) Candidate VLTI Configurations for the GENIE Nulling ExperimentAbsil, Olivier ; Gondoin, P.; Erd, C. et alin Deming, Drake; Seager, Sara (Eds.) Scientific Frontiers in Research on Extrasolar Planets (2003)The European Space Agency (ESA) and the European Southern Observatory (ESO) initiate a definition study for a Ground-based European Nulling Interferometer Experiment (Darwin-GENIE). The experiment will ... [more ▼]The European Space Agency (ESA) and the European Southern Observatory (ESO) initiate a definition study for a Ground-based European Nulling Interferometer Experiment (Darwin-GENIE). The experiment will use the Very Large Telescope Interferometer (VLTI) operating on Mount Paranal (Chile). The objective of GENIE is to gain experience in the manufacture and operation of a nulling interferometer using a design concept and technology representative of the ESA IRSI-Darwin space mission. GENIE will prepare the IRSI-Darwin science program through a systematic search for exozodiacal dust clouds around IRSI-Darwin candidate targets. GENIE also aims to perform IRSI-Darwin related science achievable from ground including the detection of low-mass companions (if possible, hot jupiters) around nearby stars. Among the variety of telescope sizes and positions on the VLTI site, candidate interferometric configurations have been identified for GENIE, taking into account the limitation imposed by the Earth's atmosphere. They include a Bracewell interferometer for exozodiacal clouds detection in the N band and a double Bracewell configuration with internal modulation for extrasolar jupiter detection in the L' band. The present paper presents the prospective performance of these configurations in light of current specifications of major VLTI subsystems. [less ▲]Detailed reference viewed: 9 (0 ULiège) 1