European Interferometry



We are contributing to the development of interferometry in Europe through the European Interferometry Initiative.

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Extrasolar planetary systems



Exozodiacal disks

We are carrying out an interferometric survey of nearby main-sequence stars for the presence of hot circumstellar dust, using the FLUOR instrument on the CHARA array and the VLTI. Follow-up characterisation of bright exozodiacal disks is attempted with various instruments (IOTA/IONIC, Keck Nuller, Fiber Nuller, etc). For more information click here ...
 
 

Debris disks

We are observing debris disks at high angular resolution with ground-based coronagraphic devices. We are involved in a Herschel Key Project (DUNES) aiming at the detection of extrasolar Kuiper belts around a large sample of nearby main sequence stars. We are also involved in the dynamical modelling of resonant structures in resolved debris disks. For more information click here ...
 
 

Proto-planetary disks

We are working on the coronagraphic imaging and physical modelling of circumstellar disks around young stars. For more information click here ...
 
 

Low-mass companions and extrasolar planets

We are using interferometry and coronagraphy to search for and characterise low-mass companions (including brown dwarfs and extrasolar planets) around young stars and main sequence stars. For more information click here ...
 
 


Space-based interferometry



FKSI and Pegase: Enabling science for Darwin

FKSI and Pegase are two projects of space-based Bracewell interferometers conceived as scientic precursors and technological demonstrators for future exo-Earth characterization missions. Their main scientific goals would be to enable the high-angular resolution study of EGPs and exozodiacal discs at infrared wavelengths. Characterization of exozodiacal discs with interferometry has been recently recommended as one of the priorities in the medium term (6-10 years) by the recently completed report of the Exoplanet Task Force (2008).

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DARWIN/TPF (Infra-Red Space Interferometer)

The search for exoplanets has gained much interest since the first discovery of a planet orbiting the star 51 Peg by Mayor and Queloz in 1995. Current techniques for exoplanet detection, such as radial velocity measurements, are well suited to detect Jupiter-sized planets, but do not have enough sensitivity to discover planets similar to our Earth. The Darwin/TPF space missions are aimed at filling this gap, by means of nulling interferometry. This special kind of interferometry is intended to suppress all the light coming from a blinding star by means of broadband destructive interference (induced by performing APS), in order to reveal the star's potential planetary companions. Once the starlight has been properly cancelled, the thermal emission from zodiacal and exo-zodiacal dust clouds becomes the main obstacle to planet detection. Internal modulation is a recent technique devised to suppress such spurious signals. It relies on rapid modulation between the outputs of two nulling interferometers sharing the same telescopes.
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Ground-based interferometry



GENIE (Ground-based European Nulling Interferometer Experiment)

Within the frame of the Darwin technology program, the European Space Agency (ESA) and the European Southern Observatory (ESO) have initiated a definition study for a ground-based technology demonstrator called GENIE. This ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The definition study will assess the technical feasibility of the experiment and establish its design, performance, programmatics and cost. If successful, the definition study will be the base for ESA and ESO to move into the hardware development, integration and exploitation phases of the GENIE project. For more information click here ...
 
 

ALADDIN (Antarctic L-band Astrophysics Discovery Demonstrator for
Interferometric Nulling)

ALADDIN is a project of nulling interferometer for Dome C (Antarctica), motivated by the need for a ground-based demonstrator for the Darwin mission. Following a preliminary industrial study, our team is involved in the design of the instrument by studying the pre-requisite technology for Darwin. In addition, we have developped in collaboration with LAOG and LESIA a performance simulation software in order to assess the scientific return of the intsrument. For more information click here ...
 
 

Fiber Nuller

The Fiber Nuller is a so called rotating nulling coronagraph developped at the Jet Propulsion Laboratory. This transportable instrument is used on the 200" Hale telescope of the Palomar Observatory. Unlike long baseline interferometers, the Fiber Nuller defines two elliptical subapertures on a single dish and make them interfering by focusing the beams directly into a single mode fiber. By a relative π phase shift of the beams, the starlight can be nulled and a relatively faint companion star can be detected. Rotation of the aperture mask on the telescope pupil results in a signal similar to that expected from a space-borne telescope system such as the proposed TPF/Darwin interferometer. The main objectives of this instrument are to look for faint companions close to bright stars and to detect and characterize circumstellar disks. For more information click here ...
 
 

Laboratory experiments

CELINE (Companion and Exoplanet detection Laboratory demonstration with an Interferometric Nulling Experiment )

This nulling testbench based on the Fiber Nuller principle aims at performing deep broadband nulls in both H and K bands, testing achromatic phase shifters developped in Liège ( i.e. the Fresnel Rhombs ), but also testing new kinds of single-mode fibers for modal filtering. For more information click here ...
 
EASO
Extragalactic Astrophysics and
Space Observations
Institut d'Astrophysique et de Géophysique, Liège University, Allée du 6 Août, 17 (Sart Tilman, Bât. B5c), 4000 Liège, Belgique Tel.: 04.366.97.55, Fax: 04.366.97.46
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