Author: "Alain Léger" / Topic: exoplanet - Searchworks@Jio Institute Digital Library Search Results

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32 results on '"Alain Léger"'

1. Nulling interferometry for the darwin mission: laboratory demonstration experiment

Author: Guy Michel, Alain Léger, Alain Labèque, Predrag Sekulic, and M. Ollivier
Subjects: Wavefront, Physics, Interferometry, Optics, business.industry, Astronomical interferometer, Darwin (spacecraft), Angular resolution, business, Optical filter, High dynamic range, Exoplanet
Abstract: The DARWIN mission is a project of the European Space Agency that should allow around 2012 the search for extrasolar planets and a spectral analysis of their potential atmosphere in order to evidence gases and particularly tracers of life. The principle of the instrument is based on the Bracewell nulling interferometer. It allows high angular resolution and high dynamic range. However, this concept, proposed more than 20 years ago, has never been experimentally demonstrated in the thermal infrared with high levels of extinction. We present here a laboratory monochromatic experiment dedicated to this goal. A theoretical and numerical approach of the question highlights a strong difficulty: the need for very clean and homogeneous wavefronts, in terms of intensity, phase and polarisation distribution. A classical interferometric approach appears to be insufficient to reach our goals. We have shown theoretically then numerically that this difficulty can be surpassed if we perform an optical filtering of the interfering beams. This technique allows us to decrease strongly the optical requirements and to view very high interferometric contrast measurements with commercial optical pieces. We present here a laboratory interferometer working at 10,6 microns, and implementing several techniques of optical filtering (pinholes and single-mode waveguides), its realisation, and its first promising results. We particularly present measurements that exhibit stable visibility levels better than 99,9% that is to say extinction levels better than 1000.
Published: 2017

2. The exoplanet program of the microarcsecond astrometric observatory Theia (Conference Presentation)

Author: Lucas Labadie, Stuart Shaklan, Fabien Malbet, Alain Léger, Alberto Krone-Martins, Celine Boehm, and Antoine Crouzier
Subjects: Telescope, Stars, Planet, Observatory, law, Astronomy, Astrophysics, Astrometry, Circumstellar habitable zone, Exoplanet, Geology, Metrology, law.invention
Abstract: The Theia mission, as a natural successor to Gaia, will be the first extremely-high-precision astrometric surveyor that may emerge from the last ESA M5 call in October 2016. A major objective of Theia in the context of this conference is the detection by astrometry of Earths and Super-Earths exoplanets in the habitable zone of nearby A to M stars. This can be done by astrometry from space if a motion of
Published: 2017

3. Microarcsecond astrometric observatory Theia: from dark matter to compact objects and nearby earths

Author: Renaud Goullioud, Mike Shao, Douglas Spolyar, Fabien Malbet, Lucas Labadie, Antoine Crouzier, Celine Boehm, Berry Holl, Guillem Anglada Escudé, Alberto Krone-Martins, Alessandro Sozzetti, and Alain Léger
Subjects: Physics, Cosmic Vision, Planetary habitability, 010308 nuclear & particles physics, Dark matter, Astronomy, Astrometry, 01 natural sciences, Exoplanet, Astrobiology, law.invention, Telescope, Planet, Observatory, law, 0103 physical sciences, 010303 astronomy & astrophysics
Abstract: Theia is a logical successor to Gaia, as a focused, very high precision astrometry mission which addresses two key science objectives of the ESA Cosmic Vision program: the nature of dark matter and the search for habitable planets. Theia addresses a number of other science cases strongly synergistic with ongoing/planned missions, such as the nature of compact objects, motions of stars in young stellar clusters, follow-up of Gaia objects of interest. Theia s "point and stare" operational mode will enable us to answer some of the most profound questions that the results of the Gaias survey will ask. Extremely-high-precision astrometry at 1-μas level can only be reached from space. The Theia spacecraft, which will carry a 0.8-m telescope, is foreseen to operate at L2 for 3,5 years. The preliminary Theia mission assessment allowed us to identify a safe and robust mission architecture that demonstrates the mission feasibility within the Soyuz ST launch envelope and a small M-class mission cost cap. We present here these features of the mission that has been submitted to the last ESA M4 call in January 2015.
Published: 2016

4. NEAT: An Astrometric Mission to Detect and Characterize Nearby Habitable Planetary Systems

Author: Fabien Malbet, Alain Léger, Renaud Goullioud, Pierre-Olivier Lagage, Antoine Crouzier, and Mike Shao
Subjects: Physics, Space and Planetary Science, Astronomy and Astrophysics, Astrometry, Planetary system, Exoplanet, Astrobiology
Abstract: Many planets have been detected so far but very few around nearby stars that could allow characterization of their atmosphere thanks to their proximity. There are known exoplanets around less than 8.3% of the FGK stars of the Solar neighborhood (d
Published: 2012

5. Deciphering Spectral Fingerprints of Habitable Exoplanets

Author: Lisa Kaltenegger, Frank Selsis, Malcolm Fridlund, Helmut Lammer, Charles Beichman, William Danchi, Carlos Eiroa, Thomas Henning, Tom Herbst, Alain Léger, René Liseau, Jonathan Lunine, Francesco Paresce, Alan Penny, Andreas Quirrenbach, Huub Röttgering, Jean Schneider, Daphne Stam, Giovanna Tinetti, and Glenn J. White
Subjects: 010504 meteorology & atmospheric sciences, Habitability, Astrophysics::Instrumentation and Methods for Astrophysics, Planets, Biosphere, Context (language use), 01 natural sciences, Agricultural and Biological Sciences (miscellaneous), First generation, Exoplanet, Astrobiology, Space and Planetary Science, Planet, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We discuss how to read a planet's spectrum to assess its habitability and search for the signatures of a biosphere.\ud After a decade rich in giant exoplanet detections, observation techniques have advanced to a level where we now have the capability to find planets of less than 10 Earth masses (MEarth) (so-called "super Earths"), which may be habitable. How can we characterize those planets and assess whether they are habitable? This new field of exoplanet search has shown an extraordinary capacity to combine research in astrophysics, chemistry, biology, and geophysics into a new and exciting interdisciplinary approach to understanding our place in the\ud Universe. The results of a first-generation mission will most likely generate an amazing scope of diverse planets\ud that will set planet formation, evolution, and our planet into an overall context.
Published: 2010

6. Origin and Formation of Planetary Systems

Author: Giovanna Tinetti, Carlos Eiroa, Huub Röttgering, Charles Beichman, Thomas Henning, Alain Léger, Willy Benz, René Liseau, Glenn J. White, William C. Danchi, Malcolm Fridlund, Andreas Quirrenbach, Günther Wuchterl, Lisa Kaltenegger, Francesco Paresce, Helmut Lammer, Jean Schneider, Christophe Sotin, Jonathan I. Lunine, Tom Herbst, C. Broeg, Alan J. Penny, Olivier Grasset, Daphne Stam, Franck Selsis, Yann Alibert, Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Physikalisches Institut [Bern], Universität Bern [Bern], Thüringer Landessternwarte Tautenburg (TLS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Universidad Autonoma de Madrid (UAM), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Department of Radio and Space Science [Göteborg], Chalmers University of Technology [Göteborg], Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Istituto Nazionale di Astrofisica (INAF), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), University College of London [London] (UCL), Department of Physics and Astronomy [Milton Keynes], The Open University [Milton Keynes] (OU), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and European Southern Observatory (ESO)
Subjects: Terrestrial exoplanets, Time Factors, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Habitability, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Planets, 01 natural sciences, Astrobiology, Kepler-47, Planet, Ice giants, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Planetary migration, Planet formation, Physics, Astronomy, Planetary system, Agricultural and Biological Sciences (miscellaneous), Exoplanet, Gas giants, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Terrestrial planet, Gases, Solar System, Astrophysics::Earth and Planetary Astrophysics, Planetary mass, Ice giant
Abstract: International audience; To estimate the occurrence of terrestrial exoplanets and maximize the chance of finding them, it is crucial to understand the formation of planetary systems in general and that of terrestrial planets in particular. We show that a reliable formation theory should not only explain the formation of the Solar System, with small terrestrial planets within a few AU and gas giants farther out, but also the newly discovered exoplanetary systems with close-in giant planets. Regarding the presently known exoplanets, we stress that our current knowledge is strongly biased by the sensitivity limits of current detection techniques (mainly the radial velocity method). With time and improved detection methods, the diversity of planets and orbits in exoplanetary systems will definitely increase and help to constrain the formation theory further. In this work, we review the latest state of planetary formation in relation to the origin and evolution of habitable terrestrial planets.
Published: 2010

7. A Roadmap for the Detection and Characterization of Other Earths

Author: Thomas Henning, René Liseau, Charles Beichman, Jonathan I. Lunine, Giovanna Tinetti, Alan J. Penny, Alain Léger, Tom Herbst, Carlos Eiroa, Helmut Lammer, Franck Selsis, Andreas Quirrenbach, William C. Danchi, Glenn J. White, Huub Röttgering, Malcolm Fridlund, Daphne Stam, Jean Schneider, Lisa Kaltenegger, Francesco Paresce, Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Universidad Autonoma de Madrid (UAM), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Department of Radio and Space Science [Göteborg], Chalmers University of Technology [Göteborg], Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Istituto Nazionale di Astrofisica (INAF), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), University College of London [London] (UCL), Department of Physics and Astronomy [Milton Keynes], and The Open University [Milton Keynes] (OU)
Subjects: Physics, 0303 health sciences, Cosmic Vision, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Agency (philosophy), Planets, 01 natural sciences, Agricultural and Biological Sciences (miscellaneous), Space exploration, Exoplanet, Astrobiology, 03 medical and health sciences, 13. Climate action, Space and Planetary Science, Planet, Extraterrestrial life, 0103 physical sciences, Darwin (spacecraft), Solar System, 010303 astronomy & astrophysics, 030304 developmental biology, Theme (narrative)
Abstract: The European Space Agency and other space agencies such as NASA recognize that the question with regard to\ud life beyond Earth in general, and the associated issue of the existence and study of exoplanets in particular, is of\ud paramount importance for the 21st century. The new Cosmic Vision science plan, Cosmic Vision 2015–2025, which is built around four major themes, has as its first theme: \ud "What are the conditions for planet formation and the emergence of life?" This main theme is addressed through further questions:\ud \ud (1) How do gas and dust give rise to stars and planets?\ud \ud (2) How will the search for and study of exoplanets eventually lead to the detection of life outside Earth (biomarkers*)?\ud \ud (3) How did life in the Solar System arise and evolve?\ud \ud Although ESA has busied itself with these issues since the beginning of the Darwin study in 1996, it has\ud become abundantly clear that, as these topics have evolved, only a very large effort, addressed from the ground\ud and from space with the utilization of different instruments and space missions, can provide the empirical results required for a complete understanding. The good news is that the problems can be addressed and solved within\ud a not-too-distant future. In this short essay, we present the present status of a roadmap related to projects that are related to the key long-term goal of understanding and characterizing exoplanets, in particular Earthlike\ud planets.
Published: 2010

8. Stabilising a nulling interferometer using optical path difference dithering

Author: Alain Labèque, Sophie Jacquinod, Michel Decaudin, Bruno Chazelas, Alain Léger, Pavel Gabor, Frank Brachet, and Marc Ollivier
Subjects: Physics, business.industry, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Stability (probability), Noise (electronics), Exoplanet, Interferometry, Optics, Space and Planetary Science, Darwin (spacecraft), Dither, business, Optical path length
Abstract: Context. Nulling interferometry has been suggested as the underlying principle for the Darwin and TPF-I exoplanet research missions. Aims. There are constraints both on the mean value of the nulling ratio, and on its stability. Instrument instability noise is most detrimental to the stability of the nulling performance. Methods. We applied a modified version of the classical dithering technique to the optical path difference in the scientific beam. Results. Using only this method, we repeatedly stabilised the dark fringe for several hours. This method alone sufficed to remove the 1/ f component of the noise in our setup for periods of 10 minutes, typically. These results indicate that performance stability may be maintained throughout the long-duration data acquisitions typical of exoplanet spectroscopy. Conclusions. We suggest that further study of possible stabilisation strategies should be an integral part of Darwin/TPF-I research and development
Published: 2008

9. NEAT: ultra-precise differential astrometry to characterize planetary systems with Earth-mass exoplanets in the vicinity of our Sun

Author: Mike Shao, Antoine Crouzier, Alain Léger, Renaud Goullioud, and Fabien Malbet
Subjects: Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astrometry, Planetary system, Earth mass, Exoplanet, law.invention, Astrobiology, Radial velocity, Telescope, Planet, law, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Discoveries of exoplanets
Abstract: The nearest solar-type stars are of prime interest for the science of exoplanets because they are the objects most suitable for direct detection and future spectroscopic investigations. Astrometry combined with radial velocity is the technique that can reveal planets with mass as small as the Earth mass in the 1 AU domain. We present in this contribution the result of a 3-year study on a mission capable to perform ultra-precise differential astrometry called NEAT (Nearby Earth Astrometric Telescope) and characterize planetary systems with Earth- mass exoplanets in the vicinity of our Sun. This mission requires exquisite calibration of the focal plane together with innovative approaches to obtain a very stable long focal telescope. This mission will be submitted in 2014 to the ESA M4 Call for Mission.
Published: 2014

10. NEAT breadboard system analysis and performance models

Author: S. Lafrasse, Alain Léger, Fabien Malbet, Alain Delboulbé, Christophe Cara, Guillermo Martin, François Hénault, Philippe Feautrier, Pierre Kern, Jean-Michel Le Duigou, Eric Staedler, and Antoine Crouzier
Subjects: Physics, Test bench, Pixel, business.industry, Astrometry, Breadboard, Exoplanet, law.invention, Metrology, Telescope, law, Aerospace engineering, business, Circumstellar habitable zone, Remote sensing
Abstract: NEAT (Nearby Earth Astrometric Telescope) is an astrometric space mission aiming at detecting Earth-like exoplanets located in the habitable zone of nearby solar-type stars. For that purpose, NEAT should be able to measure stellar centroids within an accuracy of 5 10 -6 pixels. In order to fulfil such stringent requirement, NEAT incorporates an interferometric metrology system measuring pixel gains and location errors. To validate this technology and assess the whole performance of the instrument, a dedicated test bench has been built at IPAG, in Grenoble (France). In this paper are summarized the main system engineering considerations allowing to define sub-systems specifications. Then we describe the general architecture of the performance models (including photometric, interferometric, and final astrometric budgets) and confront their predictions with the experimental results obtained on the test bench. It is concluded that most of error items are well understood, although some of them deserve further investigations.
Published: 2014

11. Nulling interferometry for the DARWIN space mission

Author: M. Ollivier, J. M. Mariotti, Alain Léger, Guy Michel, Predrag Sekulic, and Jacqueline Brunaud
Subjects: Physics, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, General Physics and Astronomy, Space (mathematics), Exoplanet, law.invention, Interferometry, Optics, law, Observatory, Spectral analysis, Darwin (spacecraft), Monochromatic color, business, Coronagraph
Abstract: The DARWIN observatory will include an interferometric instrument dedicated to the search for and spectral analysis of extrasolar planets. This instrument is based on the principle of Bracewell's interferometric coronograph or nulling interferometer, proposed in 1978, but at present never experimentally demonstrated in the thermal infrared with high extinctions. We have shown that high interferometric extinctions can only be obtained with `classical' optical pieces if the beams are cleaned by optical filtering during the recombination. After a short reminder of the nulling interferometer, we present different techniques of optical filtering to perform it. Then, we present a laboratory experimental bench we have constructed, which allows us, at present, to exhibit a monochromatic stable interferometric extinction better than 103. Finally, we discuss this method, applied to ground-based telescopes.
Published: 2001

12. Detection and Characterization of earth-like Planets

Author: M. Ollivier, J. M. Mariotti, Alain Léger, and Bertrand Mennesson
Subjects: 010504 meteorology & atmospheric sciences, Astronomy, Astrometry, 01 natural sciences, Occultation, Exoplanet, Astrobiology, Radial velocity, Planetary science, Planet, Extraterrestrial life, Earth (chemistry), Astrophysics::Earth and Planetary Astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: Indirect methods of detection of exo-planets (by radial velocity, astrometry, occultations,...) have revealed recently the first cases of exo-planets, and will in the near future expand our knowledge of these systems. They will provide statistical informations on the dynamical parameters: semi-major axis, eccentricities, inclinations,... But the physical nature of these planets will remain mostly unknown. Only for the larger ones (exo-Jupiters), an estimate of the mass will be accessible. To characterize in more details Earth-like exo-planets, direct detection (i.e., direct observation of photons from the planet) is required. This is a much more challenging observational program. The exo-planets are extremely faint with respect to their star: the contrast ratio is about 10−10at visible wavelengths. Also the angular size of the apparent orbit is small, typically 0.1 second of arc. While the first point calls for observations in the infrared (where the contrast goes up to 10−7) and with a coronograph, the latter implies using an interferometer. Several space projects combining these techniques have been recently proposed. They aim at surveying a few hundreds of nearby single solar-like stars in search for Earth-like planets, and at performing a low resolution spectroscopic analysis of their infrared emission in order to reveal the presence in the atmosphere of the planet of CO H2O and O3. The latter is a good tracer of the presence of oxygen which could be, like on our Earth, released by biological activity. Although extremely ambitious, these projects could be realized using space technology either already available or in development for others missions. They could be built and launched during the first decades on the next century.
Published: 1997

13. NEAT: an astrometric mission to detect nearby planetary systems down to the Earth mass

Author: Michel Delpech, Fabien Malbet, Renaud Goullioud, P. O. Lagage, Mike Shao, Antoine Crouzier, and Alain Léger
Subjects: Physics, Cosmic Vision, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astrometry, Orbital mechanics, Planetary system, Earth mass, Exoplanet, Astrobiology, law.invention, Telescope, law, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Circumstellar habitable zone, Astrophysics::Galaxy Astrophysics
Abstract: The NEAT (Nearby Earth Astrometric Telescope) mission is a proposition for an ESA space M-size mission within the Cosmic Vision 2015-2025 plan. The main scientific goal of the NEAT mission is to detect and characterize planetary systems in an exhaustive way down to one Earth mass in the habitable zone and further away, around nearby stars for F, G, and K spectral types. This survey would provide the actual planetary masses, the full characterization of the orbits including their inclination, for all the components of the planetary system down to that mass limit. NEAT will continue the work performed by Hipparcos and Gaia by reaching a precision that is improved by two orders of magnitude on pointed targets. We report in this paper the status of the work being carried out to technically validate NEAT.
Published: 2013

14. High precision astrometry mission for the detection and characterization of nearby habitable planetary systems with the Nearby Earth Astrometric Telescope (NEAT)

Author: Olivier Absil, Damien Ségransan, Emmanuel Hinglais, Helmut Lammer, Charles S. Cockell, Frédéric Arenou, Philippe Feautrier, David Hobbs, Alain Chelli, Nicolas Rambaux, Hans Zinnecker, Charles A. Beichman, Andreas Quirrenbach, Jacques Laskar, Thierry Forveille, Glenn J. White, Johannes Sahlmann, Alain Léger, Didier Queloz, Alberto Krone-Martins, Eva Villaver, André Moitinho de Almeida, Christoph Mordasini, Jesus Maldonado, Huub Röttgering, Wesley A. Traub, Fabien Malbet, Alessandro Sozzetti, Anthony G. A. Brown, Stefano Minardi, Anne-Marie Lagrange, Sean N. Raymond, Renaud Goullioud, Paulo J. V. Garcia, Lucas Labadie, Björn Jakobsson, Christophe Cara, Peter A. Schuller, Alexandre Humberto Andrei, Jean Surdej, Gilles Durand, Jonathan I. Lunine, Gilles Duvert, Carlos Eiroa, Franck Selsis, René Liseau, Michael Shao, Yann Alibert, P. O. Lagage, Lisa Kaltenegger, Manuel Mercier, N. Meunier, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Universidad Autonoma de Madrid (UAM), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Department of Radio and Space Science [Göteborg], Chalmers University of Technology [Göteborg], Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), Planetary and Space Sciences Research Institute [Milton Keynes] (PSSRI), Centre for Earth, Planetary, Space and Astronomical Research [Milton Keynes] (CEPSAR), The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), M2A 2012, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Instituto de Astronomia, Geofisica e Ciencias Atmosfericas (IAGCAUSP), Universidade de São Paulo (USP), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Université Pierre et Marie Curie - Paris 6 (UPMC), SSE 2012, Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Department of Physics and Astronomy [Milton Keynes], The Open University [Milton Keynes] (OU), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universidad Autónoma de Madrid (UAM), Harvard University-Smithsonian Institution, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Genève = University of Geneva (UNIGE), Universität Heidelberg [Heidelberg] = Heidelberg University, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Universidade de São Paulo = University of São Paulo (USP), Universiteit Leiden, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Harvard University [Cambridge]-Smithsonian Institution, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrophysique de l'observatoire de Besançon (LAOB), Departement d'AstroNOmie Fondamentale (DANOF), Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)
Subjects: [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, Primary mirror, Telescope, law, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Astrometry, Planetary system, Exoplanet, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Stars, Space and Planetary Science, Physics::Space Physics, Instrumentation and Methods for Astrophysics, Earth and Planetary Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Circumstellar habitable zone, Astrophysics - Earth and Planetary Astrophysics
Abstract: (abridged) A complete census of planetary systems around a volume-limited sample of solar-type stars (FGK dwarfs) in the Solar neighborhood with uniform sensitivity down to Earth-mass planets within their Habitable Zones out to several AUs would be a major milestone in extrasolar planets astrophysics. This fundamental goal can be achieved with a mission concept such as NEAT - the Nearby Earth Astrometric Telescope. NEAT is designed to carry out space-borne extremely-high-precision astrometric measurements sufficient to detect dynamical effects due to orbiting planets of mass even lower than Earth's around the nearest stars. Such a survey mission would provide the actual planetary masses and the full orbital geometry for all the components of the detected planetary systems down to the Earth-mass limit. The NEAT performance limits can be achieved by carrying out differential astrometry between the targets and a set of suitable reference stars in the field. The NEAT instrument design consists of an off-axis parabola single-mirror telescope, a detector with a large field of view made of small movable CCDs located around a fixed central CCD, and an interferometric calibration system originating from metrology fibers located at the primary mirror. The proposed mission architecture relies on the use of two satellites operating at L2 for 5 years, flying in formation and offering a capability of more than 20,000 reconfigurations (alternative option uses deployable boom). The NEAT primary science program will encompass an astrometric survey of our 200 closest F-, G- and K-type stellar neighbors, with an average of 50 visits. The remaining time might be allocated to improve the characterization of the architecture of selected planetary systems around nearby targets of specific interest (low-mass stars, young stars, etc.) discovered by Gaia, ground-based high-precision radial-velocity surveys., Accepted for publication in Experimental Astronomy. The full member list of the NEAT proposal and the news about the project are available at http://neat.obs.ujf-grenoble.fr. The final publication is available at http://www.springerlink.com
Published: 2012
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15. Toward the stability required for direct observations of exoplanets with nulling interferometry technique

Author: Alain Léger, Peter A. Schuller, Philippe Duret, and Olivier Demangeon
Subjects: Physics, Stars, Interferometry, Test bench, Optics, Planet, business.industry, Orbit (dynamics), Dither, business, Stability (probability), Exoplanet
Abstract: In the literature, one can find requirements for nulling IR interferometry in terms of nulling ratio nl and stability of this nulling ratio σ nl for the observation of an exo-Earth in a 1AU orbit around a solar type star located at 10pc from the Earth: nl = 10 -5 between 7 and 20 μm and σ nl = 3 · 10 -9 over 10 days. 1 These requirements are very demanding. We report on studies made to obtain the technological requirements in terms of nulling ratio and stability of this nulling ratio as function of the targeted planets and stars. In addition we present methods of dithering developed for the NULLTIMATE test bench to achieve the maximum stability.
Published: 2010

16. Stellar aspects of habitability--characterizing target stars for terrestrial planet-finding missions

Author: Lisa Kaltenegger, Carlos Eiroa, Ignasi Ribas, Francesco Paresce, Martin Leitzinger, Petra Odert, Arnold Hanslmeier, Malcolm Fridlund, Helmut Lammer, Charles Beichman, William Danchi, Thomas Henning, Tom Herbst, Alain Léger, René Liseau, Jonathan Lunine, Alan Penny, Andreas Quirrenbach, Huub Röttgering, Frank Selsis, Jean Schneider, Daphne Stam, Giovanna Tinetti, Glenn J. White, Institut de Ciencies de l'Espai [Barcelona] (ICE-CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Southern Observatory (ESO), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, and Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Computer science, media_common.quotation_subject, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Planets, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Star catalogue, Astrobiology, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Habitability, Astrophysics::Instrumentation and Methods for Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Agricultural and Biological Sciences (miscellaneous), Exoplanet, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sky, Terrestrial planet, Darwin (spacecraft), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: In this paper we present and discuss the criteria for selecting potential target stars suitable for the search for Earth like planets, with a special emphasis on the stellar aspects of habitability. Missions that search for terrestrial exoplanets will explore the presence and habitability of Earth-like exoplanets around several hundred nearby stars, mainly F, G, K, and M stars. The evaluation of the list of potential target systems in order to develop mission concepts for a search for Terrestrial Exoplanets is essential. Using the Darwin All Sky Star Catalogue (DASSC), we discuss the selection criteria, configuration dependent sub-catalogues and the implication of stellar activity for habitability., 14 pages, 4 figures, Astrobiology, 10, 1,2010
Published: 2010

17. The far future of exoplanet direct characterization

Author: Thomas Henning, William C. Danchi, Alan J. Penny, Glenn J. White, René Liseau, Alain Léger, Carlos Eiroa, Lisa Kaltenegger, Francesco Paresce, Franck Selsis, Andreas Quirrenbach, Malcolm Fridlund, Jonathan I. Lunine, Giovanna Tinetti, Huub Roettgering, Jean Schneider, Daphne Stam, Tom Herbst, Helmut Lammer, Charles Beichman, Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), SLAC National Accelerator Laboratory (SLAC), Stanford University, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), European Southern Observatory (ESO), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, NASA Goddard Space Flight Center (GSFC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, SRON Netherlands Institute for Space Research (SRON), University College of London [London] (UCL), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Heidelberg [Heidelberg] = Heidelberg University, Universiteit Leiden, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Computer science, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Spectrum Analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Direct imaging, Astrophysics, 01 natural sciences, Agricultural and Biological Sciences (miscellaneous), Exoplanet, Characterization (materials science), Astrobiology, Space and Planetary Science, 0103 physical sciences, Fourth generation, Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Forecasting, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: In this outlook we describe what could be the next steps of the direct characterization of habitable exoplanets after first the medium and large mission projects and investigate the benefits of the spectroscopic and direct imaging approaches. We show that after third and fourth generation missions foreseeable for the next 100 years, we will face a very long era before being able to see directly the morphology of extrasolar organisms., Draft of a paper accepted in Astrobiology
Published: 2010

18. The Search for Worlds Like Our Own

Author: Peter R. Lawson, Oliver P. Lay, Luigi D'Arcio, Mikael Kilter, Franck Selsis, William C. Danchi, Jonathan I. Lunine, René Liseau, Charles Beichman, Tom Herbst, Charles Hanot, Alan J. Penny, Thomas Henning, Huub Röttgering, Carlos Eiroa, Philippe Gondoin, Lisa Kaltenegger, Francesco Paresce, Anna-Maria Stankov, Malcolm Fridlund, Christian Erd, Michael Devirian, A. Karlsson, Jean Schneider, Roland den Hartog, Glenn J. White, Olivier Absil, Kenneth J. Johnston, Alain Léger, Giovanna Tinetti, Daniel R. Coulter, Daphne Stam, Andreas Quirrenbach, Denis Defrere, Helmut Lammer, Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Universidad Autonoma de Madrid (UAM), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Department of Radio and Space Science [Göteborg], Chalmers University of Technology [Göteborg], Istituto Nazionale di Astrofisica (INAF), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Department of Physics and Astronomy [Milton Keynes], The Open University [Milton Keynes] (OU), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, University College of London [London] (UCL), NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Harvard-Smithsonian Center for Astrophysics (CfA), and Smithsonian Institution-Harvard University [Cambridge]
Subjects: Time Factors, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], media_common.quotation_subject, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Planets, 01 natural sciences, Kepler, Astrobiology, Life, Planet, Heresy, 0103 physical sciences, Humans, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common, Copernicus, Physics, Habitability, Atmosphere, Agricultural and Biological Sciences (miscellaneous), Exoplanet, Space and Planetary Science, Research Design, Darwin (spacecraft), Solar System, Classics
Abstract: International audience; The direct detection of Earth-like exoplanets orbiting nearby stars and the characterization of such planets -- particularly, their evolution, their atmospheres, and their ability to host life -- constitute a significant problem. The quest for other worlds as abodes of life has been one of mankind's great questions for several millennia. For instance, as stated by Epicurus 300 BC: Other worlds, with plants and other living things, some of them similar and some of them different from ours, must exist. Demokritos from Abdera (460-370 BC), the man who invented the concept of indivisible small parts - atoms - also held the belief that other worlds exist around the stars and that some of these worlds may be inhabited by life-forms. The idea of the plurality of worlds and of life on them has since been held by scientists like Johannes Kepler and William Herschel, among many others. Here, one must also mention Giordano Bruno. Born in 1548, Bruno studied in France and came into contact with the teachings of Nicolas Copernicus. He wrote the book De l'Infinito, Universo e Mondi in 1584, in which he claimed that the Universe was infinite, that it contained an infinite amount of worlds like Earth, and that these worlds were inhabited by intelligent beings. At the time, this was extremely controversial, and eventually Bruno was arrested by the church and burned at the stake in Rome in 1600, as a heretic, for promoting this and other equally confrontational issues (though it is unclear exactly which idea was the one that ultimately brought him to his end). In all the aforementioned cases, the opinions and results were arrived at through reasoning not by experiment. We have only recently acquired the technological capability to observe planets orbiting stars other than 6our Sun; acquisition of this capability has been a remarkable feat of our time. We show in this introduction to the Habitability Primer that mankind is at the dawning of an age when, by way of the scientific method and 21st-century technology, we will be able to answer this fascinating controversial issue that has persisted for at least 2500 years.
Published: 2010

19. Dynamical Habitability of Planetary Systems

Author: Glenn J. White, Richard P. Schwarz, Barbara Funk, Helmut Lammer, Tom Herbst, René Liseau, William C. Danchi, Carlos Eiroa, Malcolm Fridlund, Lisa Kaltenegger, Francesco Paresce, Alan J. Penny, Andreas Quirrenbach, Huub Röttgering, Elke Pilat-Lohinger, Jonathan I. Lunine, Jean Schneider, Alain Léger, Giovanna Tinetti, Eric Bois, Daphne Stam, Rudolf Dvorak, Franck Selsis, Thomas Henning, Charles Beichman, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), Universidad Autonoma de Madrid (UAM), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Department of Radio and Space Science [Göteborg], Chalmers University of Technology [Göteborg], Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Istituto Nazionale di Astrofisica (INAF), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), University College of London [London] (UCL), Department of Physics and Astronomy [Milton Keynes], and The Open University [Milton Keynes] (OU)
Subjects: Physics, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Planets, Astronomy, Planetary system, 01 natural sciences, Agricultural and Biological Sciences (miscellaneous), Habitability of orange dwarf systems, Exoplanet, Astrobiology, Kepler-47, 13. Climate action, Space and Planetary Science, Planet, Jupiter, 0103 physical sciences, Terrestrial planet, Solar System, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Planetary mass, 0105 earth and related environmental sciences, Planetary migration
Abstract: International audience; The problem of the stability of planetary systems, a question that concerns only multiplanetary systems that host at least two planets, is discussed. The problem of mean motion resonances is addressed prior to discussion of the dynamical structure of the more than 350 known planets. The difference with regard to our own Solar System with eight planets on low eccentricity is evident in that 60% of the known extrasolar planets have orbits with eccentricity e > 0.2. We theoretically highlight the studies concerning possible terrestrial planets in systems with a Jupiter-like planet. We emphasize that an orbit of a particular nature only will keep a planet within the habitable zone around a host star with respect to the semimajor axis and its eccentricity. In addition, some results are given for individual systems (e.g., Gl777A) with regard to the stability of orbits within habitable zones. We also review what is known about the orbits of planets in double-star systems around only one component (e.g., gamma Cephei) and around both stars (e.g., eclipsing binaries).
Published: 2010

20. Origin and Evolution of Life on Terrestrial Planets

Author: René Liseau, Charles Beichman, Jonathan I. Lunine, Thomas Henning, Lisa Kaltenegger, William C. Danchi, Francesco Paresce, Giovanna Tinetti, Franck Selsis, Gerda Horneck, N. K. Belisheva, Tom Herbst, Glenn J. White, A. Brack, Daphne Stam, Andreas Quirrenbach, Alain Léger, Huub Röttgering, A. Bérces, Jean Schneider, Charles S. Cockell, Carlos Eiroa, Alan J. Penny, Helmut Lammer, Malcolm Fridlund, Centre de biophysique moléculaire (CBM), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Planetary and Space Sciences Research Institute [Milton Keynes] (PSSRI), Centre for Earth, Planetary, Space and Astronomical Research [Milton Keynes] (CEPSAR), The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Universidad Autonoma de Madrid (UAM), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Department of Radio and Space Science [Göteborg], Chalmers University of Technology [Göteborg], Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Istituto Nazionale di Astrofisica (INAF), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), University College of London [London] (UCL), Department of Physics and Astronomy [Milton Keynes], and The Open University [Milton Keynes] (OU)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Planets, Environment, 01 natural sciences, Physics::Geophysics, Astrobiology, Life, Planet, Abiogenesis, Galactic habitable zone, Origin of life, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Ions, Radiation, Astronomy, Biosphere, Agricultural and Biological Sciences (miscellaneous), Biological Evolution, Exoplanet, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Organic molecules, Circumstellar habitable zone
Abstract: After Earth's origin, our host star, the Sun, was shining 20–25% less brightly than today. Without greenhouselike\ud conditions to warm the atmosphere, our early planet would have been an ice ball, and life may never have evolved. But life did evolve, which indicates that greenhouse gases must have been present on early Earth to warm the planet. Evidence from the geological record indicates an abundance of the greenhouse gas CO2. CH4 was probably present as well; and, in this regard, methanogenic bacteria, which belong to a diverse group of anaerobic prokaryotes that ferment CO2 plus H2 to CH4, may have contributed to modification of the early atmosphere. Molecular oxygen was not present, as is indicated by the study of rocks from that era, which contain iron carbonate rather than iron oxide. Multicellular organisms originated as cells within colonies\ud that became increasingly specialized. The development of photosynthesis allowed the Sun's energy to be harvested directly by life-forms. The resultant oxygen accumulated in the atmosphere and formed the ozone layer in the upper atmosphere. Aided by the absorption of harmful UV radiation in the ozone layer, life colonized Earth's surface. Our own planet is a very good example of how life-forms modified the atmosphere over the planets' lifetime. We show that these facts have to be taken into account when we discover and characterize atmospheres of Earth-like exoplanets. If life has originated and evolved on a planet, then it should be expected that a strong co-evolution occurred between life and the atmosphere, the result of which is the planet's climate.
Published: 2010

21. Co-evolution of atmospheres, life, and climate

Author: René Liseau, Lisa Kaltenegger, Francesco Paresce, Glenn J. White, Thomas Henning, Daphne Stam, Malcolm Fridlund, Andreas Quirrenbach, Huub Röttgering, Alan J. Penny, Helmut Lammer, Tom Herbst, Heike Rauer, Giovanna Tinetti, J. Schneider, Jonathan I. Lunine, Carlos Eiroa, Alain Léger, William C. Danchi, Charles Beichman, Franck Selsis, John Lee Grenfell, DLR Institute of Planetary Research, German Aerospace Center (DLR), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], NASA ExoPlanet Science Institute (NExScI), California Institute of Technology (CALTECH), NASA Goddard Space Flight Center (GSFC), Universidad Autonoma de Madrid (UAM), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Department of Radio and Space Science [Göteborg], Chalmers University of Technology [Göteborg], Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Istituto Nazionale di Astrofisica (INAF), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Observatoire de Paris - Site de Meudon (OBSPM), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), University College of London [London] (UCL), Department of Physics and Astronomy [Milton Keynes], and The Open University [Milton Keynes] (OU)
Subjects: Atmospheres, 010504 meteorology & atmospheric sciences, Ultraviolet Rays, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Climate, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Planets, FOS: Physical sciences, chemistry.chemical_element, Geologic record, 01 natural sciences, Oxygen, Astrobiology, Atmosphere, Ozone, Planet, 0103 physical sciences, Ozone layer, Photosynthesis, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Exoplanets, Early Earth, Biomarker, Agricultural and Biological Sciences (miscellaneous), Exoplanet, chemistry, 13. Climate action, Space and Planetary Science, Greenhouse gas, Sunlight, Environmental science, Solar System, Evolution, Planetary, Astrophysics - Earth and Planetary Astrophysics
Abstract: After Earth's origin, our host star, the Sun, was shining 20–25% less brightly than today. Without greenhouselike\ud conditions to warm the atmosphere, our early planet would have been an ice ball, and life may never have evolved. But life did evolve, which indicates that greenhouse gases must have been present on early Earth to warm the planet. Evidence from the geological record indicates an abundance of the greenhouse gas CO2. CH4 was probably present as well; and, in this regard, methanogenic bacteria, which belong to a diverse group of anaerobic prokaryotes that ferment CO2 plus H2 to CH4, may have contributed to modification of the early atmosphere. Molecular oxygen was not present, as is indicated by the study of rocks from that era, which contain iron carbonate rather than iron oxide. Multicellular organisms originated as cells within colonies\ud that became increasingly specialized. The development of photosynthesis allowed the Sun's energy to be harvested directly by life-forms. The resultant oxygen accumulated in the atmosphere and formed the ozone layer in the upper atmosphere. Aided by the absorption of harmful UV radiation in the ozone layer, life colonized Earth's surface. Our own planet is a very good example of how life-forms modified the atmosphere over the planets' lifetime. We show that these facts have to be taken into account when we discover and characterize atmospheres of Earth-like exoplanets. If life has originated and evolved on a planet, then it should be expected that a strong co-evolution occurred between life and the atmosphere, the result of which is the planet's climate.
Published: 2010

22. Darwin—an experimental astronomy mission to search for extrasolar planets

Author: Hervé Cottin, Helmut Lammer, Thomas Henning, Denis Mourard, Willy Benz, Carlos Eiroa, Charles Beichman, Olivier Absil, Glenn J. White, Denis Defrere, Andreas Quirrenbach, Laurent M. Mugnier, Frances Westall, Charles S. Cockell, C. Moutou, Alain Léger, René Liseau, Pascale Bordé, Malcolm Fridlund, Huub Röttgering, Lucas Labadie, Eugene Serabyn, B. Chazelas, Marc Ollivier, Stefan Martin, Tom Herbst, Lisa Kaltenegger, Oliver P. Lay, Kenneth J. Johnston, William C. Danchi, Ralf Launhardt, Francesco Paresce, Yves Rabbia, Franck Selsis, Vincent Coudé du Foresto, Peter R. Lawson, Nuno C. Santos, Daniel Rouan, Alain Chelli, A. Brack, Jan-Willem den Herder, Dimitri Mawet, Planetary and Space Sciences Research Institute [Milton Keynes] (PSSRI), Centre for Earth, Planetary, Space and Astronomical Research [Milton Keynes] (CEPSAR), The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), Physikalisches Institut [Bern], Universität Bern [Bern], Centre de biophysique moléculaire (CBM), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), SPEC Inc., Laboratoire de Recherche en Informatique (LRI), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), European Southern Observatory (ESO), Landessternwarte Königstuhl [ZAH] (LSW), Universität Heidelberg [Heidelberg], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Engineering Department, University of Cambridge [UK] (CAM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Universität Bern [Bern] (UNIBE), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg] = Heidelberg University, Universiteit Leiden, Universidade do Porto = University of Porto, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université d'Orléans (UO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), ONERA, and Universidade do Porto [Porto]
Subjects: Systematic error, Physics, Cosmic Vision, Habitable zone, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Exoplanets, Exomoon, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, Astronomy and Astrophysics, 01 natural sciences, Exoplanet, Astrobiology, 010309 optics, Direct imaging of exoplanets, Space and Planetary Science, Primary (astronomy), 0103 physical sciences, Darwin (spacecraft), Nulling interferometry, Interferometer, 010303 astronomy & astrophysics, Circumstellar habitable zone
Abstract: International audience; As a response to ESA call for mission concepts for its Cosmic Vision 2015–2025 plan, we propose a mission called Darwin. Its primary goal is the study of terrestrial extrasolar planets and the search for life on them. In this paper, we describe different characteristics of the instrument.
Published: 2009

23. Mass loss from 'Hot Jupiters'—Implications for CoRoT discoveries, Part II: Long time thermal atmospheric evaporation modeling

Author: Yu. N. Kulikov, Magali Deleuil, D. Langmayr, T. Penz, Nikolai V. Erkaev, Helmut Lammer, Alain Léger, Giuseppina Micela, Cesare Cecchi-Pestellini, Helfried K. Biernat, Pierre Barge, Franck Selsis, INAF - Osservatorio Astronomico di Palermo, Istituto Nazionale di Astrofisica (INAF), Institute of Computational Modelling, Russian Academy of Sciences [Moscow] (RAS), Polar Geophysical Institute of Russian Academy of Sciences (PGI), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), INAF - Osservatorio Astronomico di Palermo (OAPa), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: Physics, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Astrophysics, 7. Clean energy, 01 natural sciences, Exoplanet, Atmosphere, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Tidal force, Hot Jupiter, Astrophysics::Solar and Stellar Astrophysics, Roche lobe, Astrophysics::Earth and Planetary Astrophysics, Thermosphere, 010303 astronomy & astrophysics, Planetary mass, Stellar evolution, 0105 earth and related environmental sciences
Abstract: We investigate the efficiency of the atmospheric mass loss due to hydrodynamic blow-off over the lifetime of the exoplanet HD209458b by studying numerically its hydrogen wind for host star X-ray and EUV (XUV) fluxes between 1 and 100 times that of the present Sun. We apply a time-dependent numerical algorithm which is able to solve the system of hydrodynamic equations straight through the transonic point of the flow including Roche lobe effects. The mass loss rates are calculated as functions of the absorbed energy in the thermosphere. Depending on the heating efficiency for a hydrogen-rich thermosphere the maximum temperature obtained in our study at 1.5 R pl by neglecting IR cooling is about 5000–10,000 K for heating efficiencies of 10% and 60%, respectively. We find that the upper atmosphere of HD209458b experiences hydrodynamic blow-off even at such low temperatures if one does not neglect gravitational effects caused by the proximity of the planet to its Roche lobe boundary. Depending on the heating efficiency, we find from the solution of the hydrodynamic equations of mass, momentum, and energy balance that energy-limited mass loss rate estimations overestimate the realistic mass loss rate at present time for HD209458b by several times. Using the maximum heating efficiency for hydrogen–rich atmospheres of 60% we find that HD209458b may experience an atmospheric mass loss rate at present time of about 3.5 × 10 10 g s - 1 . The mass loss rate evolves to higher values for higher XUV fluxes expected during the early period of the planet's host star evolution, reaching values of several times 10 12 g s - 1 . The integrated mass loss is found to be between 1.8% and 4.4% of the present mass of HD209458b. We found that the influence of the stellar tidal forces on atmospheric loss (the Roche lobe effect) is not significant at 0.045 AU. For a similar exoplanet, but at closer orbital distances ⩽ 0.02 AU , the combined effect of the Roche lobe and the high XUV radiation result in much higher thermal loss rates of about 2.6 × 10 11 g s - 1 and even more for early stages. This leads to a total loss over 4 Gyr of 27.5% of the planetary mass.
Published: 2008

24. IMPACT OFηEarthON THE CAPABILITIES OF AFFORDABLE SPACE MISSIONS TO DETECT BIOSIGNATURES ON EXTRASOLAR PLANETS

Author: Denis Defrere, Olivier Absil, Fabien Malbet, Lucas Labadie, and Alain Léger
Subjects: Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, 7. Clean energy, Space exploration, Exoplanet, law.invention, Stars, 13. Climate action, Space and Planetary Science, Planet, law, Astronomical interferometer, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Coronagraph, Circumstellar habitable zone, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present an analytic model to estimate the capabilities of space missions dedicated to the search for biosignatures in the atmosphere of rocky planets located in the habitable zone of nearby stars. Relations between performance and mission parameters such as mirror diameter, distance to targets, and radius of planets, are obtained. Two types of instruments are considered: coronagraphs observing in the visible, and nulling interferometers in the thermal infrared. Missions considered are: single-pupil coronagraphs with a 2.4 m primary mirror, and formation flying interferometers with 4 x 0.75 m collecting mirrors. The numbers of accessible planets are calculated as a function of {\eta}earth. When Kepler gives its final estimation for {\eta}earth, the model will permit a precise assessment of the potential of each instrument. Based on current estimations, {\eta}earth = 10% around FGK stars and 50% around M stars, the coronagraph could study in spectroscopy only ~1.5 relevant planets, and the interferometer ~14.0. These numbers are obtained under the major hypothesis that the exozodiacal light around the target stars is low enough for each instrument. In both cases, a prior detection of planets is assumed and a target list established. For the long-term future, building both types of spectroscopic instruments, and using them on the same targets, will be the optimal solution because they provide complementary information. But as a first affordable space mission, the interferometer looks the more promising in term of biosignature harvest., Comment: Accepted by ApJ
Published: 2015

25. Instrumental stability requirements for exoplanet detection with a nulling interferometer: variability noise as a central issue

Author: Alain Labèque, Pascal Bordé, Claude Valette, Frank Brachet, Olivier Absil, Alain Léger, Bruno Chazelas, Marc Ollivier, Bertrand Mennesson, Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Atom interferometer, business.industry, Materials Science (miscellaneous), 01 natural sciences, Stability (probability), Noise (electronics), Industrial and Manufacturing Engineering, Exoplanet, Metrology, law.invention, 010309 optics, Telescope, Interferometry, Optics, law, 0103 physical sciences, Darwin (spacecraft), Business and International Management, business, 010303 astronomy & astrophysics
Abstract: International audience; We revisit the nulling interferometer performances that are needed for direct detection and the spectroscopic analysis of exoplanets, e.g., with the DARWIN [European Space Agency-SCI 12 (2000)] or TPF-I [JPL Publ. 05-5, (2005)] missions. Two types of requirement are found, one concerning the mean value of the instrumental nulling function and another regarding its stability. The stress is usually put on the former. It is stringent at short wavelengths but somewhat relaxed at longer wavelengths. The latter, which we call the variability noise condition, does not usually receive enough attention. It is required regardless of telescope size and stellar distance. The results from three nulling experiments performed in laboratories around the world are reported and compared with the requirements. All three exhibit 1/f noise that is incompatible with the performances required by the mission. As pointed out by Lay [Appl. Opt. 43, 6100-6123 (2004)], this stability problem is not fully solved by modulation techniques. Adequate solutions must be found that are likely to include servo systems using the stellar signal itself as a reference and internal metrology with high stability.
Published: 2006

26. The Nulltimate project: building and testing, at low temperature, achromatic phase shifters to prepare the Darwin mission

Author: Bruno Chazelas, Thierry Lépine, Claude Valette, Frank Brachet, Philippe Blache, Alain Léger, Christian Commeaux, Marc Ollivier, Alain Labèque, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Test bench, Spacecraft, business.industry, Computer science, Frame (networking), Context (language use), Exoplanet, law.invention, Achromatic lens, law, Planet, Systems engineering, Darwin (spacecraft), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Phase shift module, Simulation
Abstract: In the context of the Darwin mission, aiming to detect terrestrial extrasolar planets, European Space Administration (ESA) has an R&D program trying to solve the crucial problems, like flotilla spacecraft control, optical spatial filtering, etc... One of the key optical devices of this mission will be Achromatic Phase Shifter (APS) able to accurately provide a 180° phase shift in the IR 6 - 18 microns range. The Institut d'Astrophysique Spatiale (IAS) is leading, in the frame of an ESA granted contract, an European consortium of 9 universities and companies, named Nulltimate, aiming to develop and test three different APS. IAS itself is in charge of the cryogenic test bench facility which is presented here.
Published: 2004

27. Nulling interferometry for the Darwin Mission: polychromatic laboratory test bench

Author: Frank Brachet, Alain Labèque, B. Pellet, Marc Ollivier, Alain Léger, Thierry Lépine, Veronique Hervier, Claude Lizambert, Bruno Chazelas, Claude Valette, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Wavefront, Test bench, business.industry, Laser, Exoplanet, law.invention, Interferometry, Optics, Achromatic lens, law, Astronomical interferometer, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], High dynamic range
Abstract: The Darwin mission is a project of the European Space Agency that should allow around 2015 the search for extrasolar planets and a spectral analysis of their potential atmospheres in order to detect gases and particularly tracers of life. The basic concept of the instrument is a Bracewell nulling interferometer. It allows high angular resolution and high dynamic range. However, this concept, proposed 25 years ago, is very difficult to implement with high rejection factor and has to be demonstrated in laboratory before being applied in space. Theoretical and numerical approaches of the question highlight strong difficulties : - The need for very clean and homogeneous wavefronts, in terms of intensity, phase and polarisation distribution ; - The need for achromatic optical devices working in a wide spectral range (typically 6 to 18 microns for the space mission). A solution to the first point is the optical filtering which has been successfully experimentally demonstrated at 10 microns using a single mode laser. We focus now on the second point and operate a test bench working in the near infrared, where the background constraints are reduced. We present this test bench and the first encouraging results in the 2-4 microns spectral range. We particularly focus on recent optical developments concerning achromatic component, and particularly the beam combiners and the phase shifter, which are keypoints of the nulling interferometry principle. Finally, we present the future of this experimental demonstration, in the thermal infrared, covering the real and whole spectral range of Darwin.
Published: 2004

28. A New Family of Planets ? Öcean Planets\'

Author: Alain Labèque, Helmut Lammer, Claude Valette, D. Despois, Marc Ollivier, Frank Brachet, Dimitri Mawet, Christophe Sotin, Franck Selsis, Bruno Chazelas, Tristan Guillot, Alain Léger, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), and arXiv, Import
Subjects: Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics (astro-ph), Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics, Space exploration, Exoplanet, Physics::Geophysics, Astrobiology, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science, Planet, Biosignature, Terrestrial planet, Astrophysics::Solar and Stellar Astrophysics, Darwin (spacecraft), Ocean planet, Astrophysics::Earth and Planetary Astrophysics, Planetary mass
Abstract: A new family of planets is considered which is between rochy terrestrial planets and gaseous giant ones: "Ocean-Planets". We present the possible formation, composition and internal models of these putative planets, including that of their ocean, as well as their possible Exobiology interest. These planets should be detectable by planet detection missions such as Eddington and Kepler, and possibly COROT (lauch scheduled in 2006). They would be ideal targets for spectroscopic missions such as Darwin/TPF., 15 pages, 3 figures submitted to Icarus notes (10 july 2003)
Published: 2004

29. New polychromatic testbed for DARWIN/TPF nulling interferometer laboratory demonstration

Author: Alain Labèque, Marc Ollivier, Thierry Lépine, Veronique Hervier, Claude Lizambert, Frank Brachet, Claude Valette, Alain Léger, and Predrag Sekulic
Subjects: Physics, Interferometry, Test bench, Optics, business.industry, Optical engineering, Testbed, Astronomical interferometer, Spectral bands, business, Exoplanet, Space exploration
Abstract: Several concept of space missions dedicated to the direct detection and analysis of extrasolar planets are based on nulling interferometry principle. This principle, which is theoretically very promising requires the capability of propagating and combining beams with very high accuracy in term of amplitude phase and polarization. In order to validate the principle of nulling interferometry, it is necessary to develop laboratory techniques of recombination. In this paper, we present a new test bench that should allow measuring rejection rate up to 105 in a large spectral band between 2 and 4 microns.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Published: 2003

30. Exo-planet detection with the COROT space mission. I. A multi-transit detection criterion

Author: Pascal Bordé, Daniel Rouan, Alain Léger, Departement de recherche SPAtiale (DESPA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and arXiv, Import
Subjects: Physics, 010504 meteorology & atmospheric sciences, Stellar population, Detection threshold, Astrophysics (astro-ph), General Physics and Astronomy, Astronomy, FOS: Physical sciences, Astrophysics, Star (graph theory), Space (mathematics), 01 natural sciences, Galaxy, Exoplanet, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We present a detection criterion for exo-planets to be used with the space mission COROT. This criterion is based on the transit method, which suggests the observation of star dimming caused by partial occulations by planetary companions. When at least three transits are observed, we show that a cross-correlation technique can yield a detection threshold, thus enabling the evaluation of the number of possible detections, assuming a model for the stellar population in the Galaxy., Comment: 7 pages, 4 figures
Published: 2001

31. Nulling interferometry for the DARWIN mission: experimental demonstration of the concept in the thermal infrared with high levels of rejection

Author: G. E. Artzner, Patrick Bouchareine, Fabien Malbet, Anne Amy-Klein, A. Vanlerberghe, Predrag Sekulic, P. O. Lagage, Guy Michel, M. Ollivier, J. M. Mariotti, Jacqueline Brunaud, Pascal Bordé, Alain Léger, Vincent Coude du Foresto, and Bertrand Mennesson
Subjects: Physics, Optical fiber, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Exoplanet, law.invention, Interferometry, Optics, law, Planet, Astronomical interferometer, Darwin (spacecraft), Pinhole (optics), Monochromatic color, business
Abstract: Present projects of space interferometers dedicated to the detection and analysis of extrasolar planets (DARWIN in Europe, TPF in the United States) are based on the nulling interferometry concept. This concept has been proposed by Bracewell in 1978 but has never been demonstrated with high values of rejection, in the thermal infrared range, where the planet detection should be performed (6 - 18 micrometers ). We have thus built a two-beam laboratory interferometer to validate this concept in a monochromatic case (at 10 micrometers ). The keypoint of our interferometer is the use of optical filtering by pinhole and optical fibers to clean the interfering beams. We present in this paper the principle of the experimental setup, its realization, and the first measurements of rejection it allowed. We also present the future developments of this interferometer.
Published: 2000

32. The Mass of CoRoT-7b

Author: Artie P. Hatzes, Malcolm Fridlund, Gil Nachmani, Tsevi Mazeh, Diana Valencia, Guillaume Hébrard, Ludmila Carone, Martin Pätzold, Stephane Udry, Francois Bouchy, Magali Deleuil, Claire Moutou, Pierre Barge, Pascal Bordé, Hans Deeg, Brandon Tingley, Rudolf Dvorak, Davide Gandolfi, Sylvio Ferraz-Mello, Günther Wuchterl, Eike Guenther, Tristan Guillot, Heike Rauer, Anders Erikson, Juan Cabrera, Szilard Csizmadia, Alain Léger, Helmut Lammer, Jörg Weingrill, Didier Queloz, Roi Alonso, Daniel Rouan, Jean Schneider, Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Exoplanet, Radial velocity, Space and Planetary Science, Planet, 0103 physical sciences, ddc:520, Terrestrial planet, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: The mass of CoRoT-7b, the first transiting superearth exoplanet, is still a subject of debate. A wide range of masses have been reported in the literature ranging from as high as 8 M_Earth to as low as 2.3 M_Earth. Although most mass determinations give a density consistent with a rocky planet, the lower value permits a bulk composition that can be up to 50% water. We present an analysis of the CoRoT-7b radial velocity measurements that uses very few and simple assumptions in treating the activity signal. By only analyzing those radial velocity data for which multiple measurements were made in a given night we remove the activity related radial velocity contribution without any a priori model. We demonstrate that the contribution of activity to the final radial velocity curve is negligible and that the K-amplitude due to the planet is well constrained. This yields a mass of 7.42 +/- 1.21 M_Earth and a mean density of rho = 10.4 +/- 1.8 gm cm^-3. CoRoT-7b is similar in mass and radius to the second rocky planet to be discovered, Kepler-10b, and within the errors they have identical bulk densities - they are virtual twins. These bulk densities lie close to the density - radius relationship for terrestrial planets similar to what is seen for Mercury. CoRoT-7b and Kepler-10b may have an internal structure more like Mercury than the Earth.
Published: 2011
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32 results on '"Alain Léger"'

1. Nulling interferometry for the darwin mission: laboratory demonstration experiment

2. The exoplanet program of the microarcsecond astrometric observatory Theia (Conference Presentation)

3. Microarcsecond astrometric observatory Theia: from dark matter to compact objects and nearby earths

4. NEAT: An Astrometric Mission to Detect and Characterize Nearby Habitable Planetary Systems

5. Deciphering Spectral Fingerprints of Habitable Exoplanets

6. Origin and Formation of Planetary Systems

7. A Roadmap for the Detection and Characterization of Other Earths

8. Stabilising a nulling interferometer using optical path difference dithering

9. NEAT: ultra-precise differential astrometry to characterize planetary systems with Earth-mass exoplanets in the vicinity of our Sun

10. NEAT breadboard system analysis and performance models

11. Nulling interferometry for the DARWIN space mission

12. Detection and Characterization of earth-like Planets

13. NEAT: an astrometric mission to detect nearby planetary systems down to the Earth mass

14. High precision astrometry mission for the detection and characterization of nearby habitable planetary systems with the Nearby Earth Astrometric Telescope (NEAT)

15. Toward the stability required for direct observations of exoplanets with nulling interferometry technique

16. Stellar aspects of habitability--characterizing target stars for terrestrial planet-finding missions

17. The far future of exoplanet direct characterization

18. The Search for Worlds Like Our Own

19. Dynamical Habitability of Planetary Systems

20. Origin and Evolution of Life on Terrestrial Planets

21. Co-evolution of atmospheres, life, and climate

22. Darwin—an experimental astronomy mission to search for extrasolar planets

23. Mass loss from 'Hot Jupiters'—Implications for CoRoT discoveries, Part II: Long time thermal atmospheric evaporation modeling

24. IMPACT OFηEarthON THE CAPABILITIES OF AFFORDABLE SPACE MISSIONS TO DETECT BIOSIGNATURES ON EXTRASOLAR PLANETS

25. Instrumental stability requirements for exoplanet detection with a nulling interferometer: variability noise as a central issue

26. The Nulltimate project: building and testing, at low temperature, achromatic phase shifters to prepare the Darwin mission

27. Nulling interferometry for the Darwin Mission: polychromatic laboratory test bench

28. A New Family of Planets ? Öcean Planets\'

29. New polychromatic testbed for DARWIN/TPF nulling interferometer laboratory demonstration

30. Exo-planet detection with the COROT space mission. I. A multi-transit detection criterion

31. Nulling interferometry for the DARWIN mission: experimental demonstration of the concept in the thermal infrared with high levels of rejection

32. The Mass of CoRoT-7b

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32 results on '"Alain Léger"'

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