References of "Absil, Olivier"
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See detailPotential of balloon payloads for in flight validation of direct and nulling interferometry concepts
Demangeon, Olivier; Ollivier, Marc; Le Duigou, Jean-Michel et al

in Danchi, W. C.; Delplancke, F.; Rajagopal, J. K. (Eds.) Optical and Infrared Interferometry II (2010, July)

While the question of low cost / low science precursors is raised to validate the concepts of direct and nulling interferometry space missions, balloon payloads offer a real opportunity thanks to their ... [more ▼]

While the question of low cost / low science precursors is raised to validate the concepts of direct and nulling interferometry space missions, balloon payloads offer a real opportunity thanks to their relatively low cost and reduced development plan. Taking into account the flight capabilities of various balloon types, we propose in this paper, several concepts of payloads associated to their flight plan. We also discuss the pros and cons of each concepts in terms of technological and science demonstration power. [less ▲]

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See detailMulti-axial integrated optics solution for POPS, a 2nd-generation VLTI fringe tracker
Tarmoul, Nassima; Hénault, François; Mourard, Denis et al

in Danchi, W. C.; Delplancke, F.; Rajagopal, J. K. (Eds.) Optical and Infrared Interferometry II (2010, July)

POPS (Planar Optical Phase Sensor) is a second-generation fringe tracker for the Very Large Telescope Interferometer (VLTI), intended to simultaneously measure the cophasing and coherencing errors of up ... [more ▼]

POPS (Planar Optical Phase Sensor) is a second-generation fringe tracker for the Very Large Telescope Interferometer (VLTI), intended to simultaneously measure the cophasing and coherencing errors of up to six Unit Telescopes (UT) or Auxiliary Telescopes (AT) in real time. The most promising concepts are probably based on the utilization of Integrated Optics (IO) components, and were the scope of a Phase A study led by Observatoire de Grenoble (LAOG). Herein is described a tentative design built around a multi-axial IO chip whose fringes are dispersed downstream on a detector array, and a Chromatic Phase Diversity algorithm presented in another paper of this conference . We depict the foreseen opto-mechanical, detection and software implementations, and provide numerical results from a realistic simulation model in terms of group and phase delay measurement accuracy and limiting magnitudes in the K band. The ultimate performance of the method is discussed and compared with the original 2[SUP]nd[/SUP] generation VLTI fringe tracker requirements. [less ▲]

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See detailDevelopment of a statistical reduction method for the Palomar Fiber Nuller
Hanot, Charles ULg; Mennesson, Bertrand; Serabyn, Eugene et al

in Danchi, W. C.; Delplancke, F.; Rajagopal, J. K. (Eds.) Optical and Infrared Interferometry II (2010, July)

A unique statistical data analysis method has been developed for reducing nulling interferometry data. The idea is to make use of the statistical distributions of the fluctuating null depths and beam ... [more ▼]

A unique statistical data analysis method has been developed for reducing nulling interferometry data. The idea is to make use of the statistical distributions of the fluctuating null depths and beam intensities to retrieve the astrophysical null depth in the presence of fluctuations. The approach yields an accuracy much better than is possible with standard data reduction methods, because the accuracy of the null depth is not limited by the sizes of the phase and intensity errors but by the uncertainties on their statistical distributions. The result is an improvement in the instrumental null depth measurement limit of roughly an order of magnitude. We show in this paper that broadband null depths of 10[SUP]-4[/SUP] can be measured in the lab with our infrared Fiber Nuller without achromatic phase shifters. On sky results are also dramatically improved, with measured contrasts up to a couple of 10[SUP]-4[/SUP] with our instrument mounted on the Hale telescope at the Palomar Observatory. This statistical analysis is not specific to our instrument and may be applicable to other interferometers. [less ▲]

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See detailDevelopment of a CELestial Infrared Nuller Experiment (CELINE) for broadband nulling and new single-mode fiber testing
Hanot, Charles ULg; Riaud, Pierre; Mawet, Dimitri et al

in Danchi, W. C.; Delpancke, F.; Rajagopal, J. K. (Eds.) Optical and Infrared Interferometry II (2010, July)

he small angular distance (<100 mas) and the huge flux ratio (107) between an Earth-like exoplanet in the socalled habitable zone and its host star makes it very difficult to direct image such systems ... [more ▼]

he small angular distance (<100 mas) and the huge flux ratio (107) between an Earth-like exoplanet in the socalled habitable zone and its host star makes it very difficult to direct image such systems. Nulling interferometry consists of a very powerful technique that combines destructively the light from two or more collectors to dim the starlight and to reveal faint companions in its vicinity. We have developed a new nulling experiment based on the fiber nuller principle. This fully symmetric reflective nulling bench aims at testing broadband nulling in both H and K bands as well as characterizing photonic fibers for modal filtering. We present in this paper the design, the development as well as preliminary results of the experiment. [less ▲]

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See detailCompared sensitivities of VLT, JWST and ELT for direct exoplanet detection in nearby stellar moving groups
Hanot, Charles ULg; Absil, Olivier ULg; Surdej, Jean ULg et al

in Oschmann, J.; Clampin, M.; MacEwen, H. (Eds.) Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave (2010, July)

In the context of exoplanet detection, a large majority of the 400 detected exoplanets have been found by indirect methods. Today, progress in the field of high contrast and angular resolution imaging has ... [more ▼]

In the context of exoplanet detection, a large majority of the 400 detected exoplanets have been found by indirect methods. Today, progress in the field of high contrast and angular resolution imaging has allowed direct images of several exoplanetary systems to be taken (cf. HR 8799, Fomalhaut and β Pic).[SUP]1-4[/SUP] In the near future, several new instruments are going to dramatically improve our sensitivity to exoplanet detection. Among these, SPHERE (Spectro Polarimetric High contrast Exoplanet REsearch) at the VLT, MIRI (Mid Infra-Red Instrument) onboard JWST and EPICS at the ELT will be equipped with coronagraphs to reveal faint objects in the vicinity of nearby stars. We made use of the Lyon group (COND) evolutionary models of young (sub-)stellar objects and exoplanets to compare the sensitivities of these different instruments using their estimated coronagraphic profiles. From this comparison, we present a catalogue of targets which are particularly well suited for the different instruments. [less ▲]

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See detailFormation and evolution of planetary systems: the impact of high-angular resolution optical techniques
Absil, Olivier ULg; Mawet, Dimitri

in Astronomy and Astrophysics Review (2010), 18(3), 317-382

The direct images of giant extrasolar planets recently obtained around several main sequence stars represent a major step in the study of planetary systems. These high-dynamic range images are among the ... [more ▼]

The direct images of giant extrasolar planets recently obtained around several main sequence stars represent a major step in the study of planetary systems. These high-dynamic range images are among the most striking results obtained by the current generation of high-angular resolution instruments which will be superseded by a new generation of instruments in the coming years. It is, therefore, an appropriate time to review the contributions of high-angular resolution visible/infrared techniques to the rapidly growing field of extrasolar planetary science. During the last 20 years, the advent of the Hubble Space Telescope, of adaptive optics on 4- to 10-m class ground-based telescopes, and of long-baseline infrared stellar interferometry, has opened a new viewpoint on the formation and evolution of planetary systems. By spatially resolving the optically thick circumstellar discs of gas and dust where planets are forming, these instruments have considerably improved our models of early circumstellar environments and have thereby provided new constraints on planet formation theories. High-angular resolution techniques are also directly tracing the mechanisms governing the early evolution of planetary embryos and the dispersal of optically thick material around young stars. Finally, mature planetary systems are being studied with an unprecedented accuracy thanks to single-pupil imaging and interferometry, precisely locating dust populations and putting into light a whole new family of long-period giant extrasolar planets. [less ▲]

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See detailThe Fomalhaut debris disk seen from every angle with interferometry
Absil, Olivier ULg

Scientific conference (2010, June 30)

We present the results of three studies of the Fomalhaut debris disk. First, VLTI/AMBER is used to determine the position angle of the oblate photosphere, and to confirm that the debris disk is in the ... [more ▼]

We present the results of three studies of the Fomalhaut debris disk. First, VLTI/AMBER is used to determine the position angle of the oblate photosphere, and to confirm that the debris disk is in the equatorial plane of its host star. Second, VLTI/VINCI measurements reveal the presence of hot dust in the inner planetary system, producing a small excess of 0.88% ± 0.12% in K band. Finally, KIN observations give additional constraints on the nature of the excess. A marginal circumstellar excess is detected at 10 µm, which we use to model the properties of the exozodiacal disk. [less ▲]

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See detailEarth-like planet imaging: why we care about exozodis (invited)
Absil, Olivier ULg

Scientific conference (2010, June 28)

We estimate the amount of exozodiacal light that can be tolerated around nearby main sequence stars without jeopardizing the detection of Earth-like exoplanets (exoEarths) with a space-based visible ... [more ▼]

We estimate the amount of exozodiacal light that can be tolerated around nearby main sequence stars without jeopardizing the detection of Earth-like exoplanets (exoEarths) with a space-based visible coronagraph or mid-infrared interferometer. We also address the possible effects of resonant structures in exozodis. We then review the sensitivity of ground-based interferometric instruments to exozodiacal disks. We show that the current performances are not sufficient to help prepare future exoEarth imaging missions, and discuss how new ground- or space-based instruments could improve the current sensitivity to exozodiacal disks down to a suitable level. [less ▲]

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See detailThe Search for Worlds Like Our Own
Fridlund, Malcolm; Eiroa, Carlos; Henning, Thomas et al

in Astrobiology (2010), 10(1), 5-17

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 ... [more ▼]

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. [less ▲]

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See detailNulling interferometry: impact of exozodiacal clouds on the performance of future life-finding space missions
Defrere, Denis ULg; Absil, Olivier ULg; den Hartog, Roland et al

in Astronomy and Astrophysics (2010), 509

Earth-sized planets around nearby stars are being detected for the first time by ground-based radial velocity and space-based transit surveys. This milestone is opening the path towards the definition of ... [more ▼]

Earth-sized planets around nearby stars are being detected for the first time by ground-based radial velocity and space-based transit surveys. This milestone is opening the path towards the definition of missions able to directly detect the light from these planets, with the identification of bio-signatures as one of the main objectives. In that respect, both ESA and NASA have identified nulling interferometry as one of the most promising techniques. The ability to study distant planets will however depend on exozodiacal dust clouds surrounding the target stars. In this paper, we assess the impact of exozodiacal dust clouds on the performance of an infrared nulling interferometer in the Emma X-array configuration. For the nominal mission architecture with 2-m aperture telescopes, we found that point-symmetric exozodiacal dust discs about 100 times denser than the solar zodiacal cloud can be tolerated in order to survey at least 150 targets during the mission lifetime. Considering modeled resonant structures created by an Earth-like planet orbiting at 1 AU around a Sun-like star, we show that the tolerable dust density for planet detection goes down to about 15 times the solar zodiacal density for face-on systems and decreases with the disc inclination. The upper limits on the tolerable exozodiacal dust density derived in this study must be considered as rather pessimistic, but still give a realistic estimation of the typical sensitivity that we will need to reach on exozodiacal discs in order to prepare the scientific programme of future Earth-like planet characterisation missions. [less ▲]

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See detailAladdin nulling instrument
Barillot, Marc; Coudé Du Foresto, Vincent; Surdej, Jean ULg et al

in Spinoglio, L.; Epchtein, N. (Eds.) 3rd ARENA Conference: An Astronomical Observatory at CONCORDIA (Dome C, Antarctica) (2010)

The ALADDIN project aims at detecting warm dust populations around nearby main sequence stars. In order to achieve the significantly improved sensitivity with respect to existing instruments, the ... [more ▼]

The ALADDIN project aims at detecting warm dust populations around nearby main sequence stars. In order to achieve the significantly improved sensitivity with respect to existing instruments, the architecture of the system is focused and optimised for the mission: ALADDIN implements the nulling interferometry technique at the focal plane of a 2-telescope interferometer mounted on a rotating structural beam. Concerning the beam combining nulling instrument, the ALADDIN design is inherited from a Definition Study of the VLTI/GENIE instrument. In this paper, we demonstrate how the ALADDIN instrument preliminary definition can be made simpler and more representative of a space instrument than GENIE thanks to both the outstanding atmospheric properties of Dome C and the dedicated architecture of the system. Finally, we discuss the compatibility of the instrument with the Antarctic environment and constraints, and underline the experimental and industrial know-how learnt from the MAII and PERSEE nulling breadboards in which our Team is also involved. [less ▲]

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See detailExozodiacal discs with ALADDIN: how faint can we detect them?
Absil, Olivier ULg; Coudé Du Foresto; Barillot, M. et al

in Spinoglio, L.; Epchtein, N. (Eds.) 3rd ARENA Conference: An Astronomical Observatory at CONCORDIA (Dome C, Antarctica) (2010)

In this paper, we describe the expected performance of ALADDIN, a nulling interferometer project optimised for operation at Dome C. After reviewing the main atmospheric parameters pertaining to infrared ... [more ▼]

In this paper, we describe the expected performance of ALADDIN, a nulling interferometer project optimised for operation at Dome C. After reviewing the main atmospheric parameters pertaining to infrared interferometry on the high Antarctic plateau, we shortly describe the ALADDIN instrument and compute its estimated performance in terms of the smallest exozodiacal dust disc density that can be detected. Our estimations are based on a thorough end-to-end software simulator previously developed for the GENIE nulling interferometer project at VLTI. We then propose a possible mission scenario, where the southern target stars of future exo-Earth characterisation missions can be surveyed for the presence of bright exozodiacal discs (>50 zodi) within one winter-over at Concordia. [less ▲]

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See detailCompared sensitivity of VLT, JWST and ELT for direct exoplanet detection in nearby stellar moving groups
Hanot, Charles ULg; Absil, Olivier ULg; Surdej, Jean ULg et al

in Villegas, Daniela; Kissler-Patig, Markus (Eds.) JWST and the ELTs: An ideal Combination (2010)

In the context of exoplanet detection, a large majority of the 400 detected exoplanets have been found by indirect methods. Today, progress in the field of high contrast imaging has allowed direct images ... [more ▼]

In the context of exoplanet detection, a large majority of the 400 detected exoplanets have been found by indirect methods. Today, progress in the field of high contrast imaging has allowed direct images of several exoplanetary systems to be taken (cf. HR 8799, Fomalhaut). In the near future, several new instruments are going to dramatically improve our sensitivity to exoplanet detection. Among these, SPHERE ( Spectro Polarimetric High contrast Exoplanet REsearch ) at the VLT, MIRI ( Mid Infra-Red Instrument) onboard JWST and the ELT will be equipped with coronagraphs to reveal faint objects in the vicinity of nearby stars. We made use of the Lyon group (COND) evolutionary models of young (sub-) stellar objects and exoplanets to compare the sensitivity of these different instruments using their estimated coronagraphic profiles. From this comparison, we present a catalogue of targets which are particularilly well suited for the different instruments. [less ▲]

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See detailAn Interferometric Study of the Fomalhaut Inner Debris Disk. I. Near-Infrared Detection of Hot Dust with VLTI/VINCI
Absil, Olivier ULg; Mennesson, Bertrand; Le Bouquin, Jean-Baptiste et al

in Astrophysical Journal (2009), 704

The innermost parts of dusty debris disks around main-sequence stars are currently poorly known due to the high contrast and small angular separation with their parent stars. Using near-infrared ... [more ▼]

The innermost parts of dusty debris disks around main-sequence stars are currently poorly known due to the high contrast and small angular separation with their parent stars. Using near-infrared interferometry, we aim to detect the signature of hot dust around the nearby A4 V star Fomalhaut, which has already been suggested to harbor a warm dust population in addition to a cold dust ring located at about 140 AU. Archival data obtained with the VINCI instrument at the VLTI are used to study the fringe visibility of the Fomalhaut system at projected baseline lengths ranging from 4 m to 140 m in the K band. A significant visibility deficit is observed at short baselines with respect to the expected visibility of the sole stellar photosphere. This is interpreted as the signature of resolved circumstellar emission, producing a relative flux of 0.88% ± 0.12% with respect to the stellar photosphere. While our interferometric data cannot directly constrain the morphology of the excess emission source, complementary data from the literature allow us to discard an off-axis point-like object as the source of circumstellar emission. We argue that the thermal emission from hot dusty grains located within 6 AU from Fomalhaut is the most plausible explanation for the detected excess. Our study also provides a revised limb-darkened diameter for Fomalhaut (theta_LD = 2.223 ± 0.022 mas), taking into account the effect of the resolved circumstellar emission. Based on observations made with ESO Telescopes at the Paranal Observatory (public VINCI commissioning data). [less ▲]

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See detailP3 panel summary: exozodiacal dust disks
Absil, Olivier ULg

Scientific conference (2009, September 18)

When observing an extrasolar planetary system, the most luminous component after the star itself is generally the light scattered and/or thermally emitted by a population of micron-sized dust grains ... [more ▼]

When observing an extrasolar planetary system, the most luminous component after the star itself is generally the light scattered and/or thermally emitted by a population of micron-sized dust grains. These grains are expected to be continuously replenished by the collisions and evaporation of larger bodies just as in our solar zodiacal cloud. Exozodiacal clouds (\exozodis") must therefore be seriously taken into account when attempting to directly image faint Earth-like planets (exoEarths, for short). This paper summarizes the oral contributions and discussions that took place during the Satellite Meeting on exozodiacal dust disks, in an attempt to address the following two questions: Do we need to solve the exozodi question? If yes, how to best solve it? [less ▲]

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See detailMulti-aperture imaging of extrasolar planetary systems (invited review)
Absil, Olivier ULg

Scientific conference (2009, September 14)

Space‐based nulling interferometry has been identified since 1978 as a promising technique to detect and characterize extrasolar Earth‐like planets. In this talk, I will review the evolution of the ... [more ▼]

Space‐based nulling interferometry has been identified since 1978 as a promising technique to detect and characterize extrasolar Earth‐like planets. In this talk, I will review the evolution of the multi‐aperture concepts dedicated to Earth‐like planet imaging during the last 30 years, and discuss the future prospects in this field. In particular, I will describe the proposed architecture for the Darwin/TPF‐I mission, which has resulted from a common optimization effort by ESA and NASA and from various industrial studies during the past decade. The main scientific and technical hard points will be critically discussed. This talk will also review the precursor instruments (present and future) that could enable future flagship interferometric missions similar to Darwin/TPF‐I. [less ▲]

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See detailExozodiacal discs with ALADDIN: how deep can we go?
Absil, Olivier ULg

Scientific conference (2009, May 12)

Studying the warm inner part of debris discs—-the extrasolar counterparts of the zodiacal dust cloud-—is of prime importance to characterise the global architecture of planetary systems. Furthermore, the ... [more ▼]

Studying the warm inner part of debris discs—-the extrasolar counterparts of the zodiacal dust cloud-—is of prime importance to characterise the global architecture of planetary systems. Furthermore, the possible presence of large quantities of warm dust around nearby main sequence stars is unanimously recognised as a major threat for future space missions dedicated to the direct detection and characterisation of Earth-like planets (either with visible/near-IR coronagraphy or mid-infrared interferometry). As of today, exozodiacal discs have been directly resolved around very few main sequence stars, at a sensitivity level of about 1000 times our zodiacal dust cloud. In this context, the ALADDIN project aims at detecting warm dust populations around nearby main sequence stars with significantly improved sensitivity. In this paper, we present a thorough study of ALADDIN's estimated performance. End-to-end simulations taking into account the specific characteristics of the Antarctic environment have been carried out, showing that a nulling interferometer coupled to a pair of 1-m class telescopes in Antarctica would perform significantly better than a similar instrument working on 8-m class telescopes in a temperate site. Exozodiacal dust density levels as low as 50 times the Solar zodiacal cloud are within reach around most Solar-type stars within 25 pc. Such performance would bring the study of exozodiacal light to a new level, and enable a fine study of terrestrial planet environments. Suitable candidate targets for direct Earth-like planet detection could then be identified among nearby main sequence stars in the Southern hemisphere, and the design of future space missions tuned to cope with the statistical occurrence of bright exozodiacal discs. [less ▲]

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See detailThe spin-orbit alignment of the Fomalhaut planetary system probed by optical long baseline interferometry
Le Bouquin, J.-B.; Absil, Olivier ULg; Benisty, M. et al

in Astronomy and Astrophysics (2009), 498

Aims. We discuss the spin-orbit orientation of the Fomalhaut planetary system composed of a central A4V star, a debris disk, and a recently discovered planetary companion. Methods: We use spectrally ... [more ▼]

Aims. We discuss the spin-orbit orientation of the Fomalhaut planetary system composed of a central A4V star, a debris disk, and a recently discovered planetary companion. Methods: We use spectrally resolved, near-IR long baseline interferometry to obtain precise spectro-astrometric measurements across the Br-gamma absorption line. The achieved astrometric accuracy of ±3 muas and the spectral resolution R=1500 from the AMBER/VLTI instrument allow us to spatially and spectrally resolve the rotating photosphere. Results: We find a position angle PA(star)=65° ± 3° for the stellar rotation axis, perpendicular to the literature measurement for the disk position angle (PA(disk)=156.0 ° ± 0.3°). This is the first time such a test could be performed for a debris disk, and in a non-eclipsing system. Additionally, our measurements suggest unexpected backward-scattering properties for the circumstellar dust grains. Conclusions: Our observations validate the standard scenario for star and planet formation in which the angular momentum of the planetary systems are expected to be colinear with the stellar spins. Based on observations collected at the VLTI (ESO Paranal, Chile), with the 082.C-0376 program from the AMBER Guaranteed Time of the Osservatorio Astrofisico di Arcetri (INAF, Italy). [less ▲]

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See detailHot dust in the inner parts of circumstellar debris discs
Absil, Olivier ULg

Scientific conference (2009, April 01)

Studying the warm inner part of debris discs—the extrasolar counterparts of the zodiacal dust cloud—is of prime importance to characterize the global architecture of planetary systems. Because of the high ... [more ▼]

Studying the warm inner part of debris discs—the extrasolar counterparts of the zodiacal dust cloud—is of prime importance to characterize the global architecture of planetary systems. Because of the high contrast and small angular separation between the star and the exozodiacal light, high-precision infrared interferometry is the best-suited tool to carry out such observations. In this paper, we review the first direct detection of an exozodiacal disc recently reported around Vega by Absil et al. (2006), and discuss the currently on-going observing efforts in this domain. We show how interferometric data can constrain the composition and the dynamics of extrasolar planetary systems, and thereby put useful constraints on the presence of small bodies and/or giant planets. First statistical trends for high-density exozodiacal discs towards a small sample of nearby main sequence stars are presented. Finally, we briefly discuss how next generation interferometric instruments could change our view of debris discs, pushing the detection limit towards meaningful density levels in the context of future life-finding missions such as Darwin/TPF. [less ▲]

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See detailExoplanet Characterization and the Search for Life
Kasting, J.; et al.; Hanot, Charles ULg et al

E-print/Working paper (2009)

Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces ... [more ▼]

Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces with spectroscopy. Rocky planets within their star's habitable zones have the highest priority, as these have the potential to harbor life. Our science goal is to find and characterize all nearby exoplanets; this requires that we measure the mass, orbit, and spectroscopic signature of each one at visible and infrared wavelengths. The techniques for doing this are at hand today. Within the decade we could answer long-standing questions about the evolution and nature of other planetary systems, and we could search for clues as to whether life exists elsewhere in our galactic neighborhood. [less ▲]

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