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Until now, just a few extrasolar planets (30 out of 860) have been found through the direct imaging method. This number should greatly improve when the next generation of High Contrast Instruments like Gemini Planet Imager (GPI) at Gemini South Telescope or SPHERE at VLT will became operative at the end of this year. In particular, the Integral Field Spectrograph (IFS), one of the SPHERE subsystems, should allow a first characterization of the spectral type of the found extrasolar planets. Here we present the results of the last performance tests that we have done on the IFS instrument at the Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) in condition as similar as possible to the ones that we will find at the telescope. We have found that we should be able to reach contrast down to 5 × 10−7 and make astrometry at sub-mas level with the instrument in the actual conditions. A number of critical issues have been identified. The resolution of these problems could allow to further improve the performance of the instrument.
If it is commonly agreed that the presence of a (moderately) close stellar companion affects the formation and the dynamical evolution of giant planets, the frequency of giant planets residing in binary systems separated by less than 100 AU is unknown. To address this issue, we have conducted with VLT/NACO a systematic adaptive optics search for moderately close stellar companions to 130 nearby solar-type stars. According to the data from Doppler surveys, half of our targets host at least one planetary companion, while the other half show no evidence for short-period giant planets. We present here the final results of our survey, which include a new series of second-epoch measurements to test for common proper motion. The new observations confirm the physical association of two companion candidates and prove the unbound status of many others. These results strengthen our former conclusion that circumstellar giant planets are slightly less frequent in binaries with mean semimajor axes between 35 and 100 AU than in wider systems or around single stars.
The recently installed Adaptive Optics system NAOS now offers diffraction limited images at the VLT. Together with the CONICA camera, NAOS provides the possibility to perform high dynamical range observations in the near IR domain. We present here NAOS-CONICA (hereafter NACO) capabilities as well as the first images of binaries obtained during NACO commissioning.
In the mid 1980s several programs were undertaken in astronomy to implement adaptive optics (AO) for visible (Doel et al. 1990; Acton and Smithson 1992) and infrared (IR) (Merkle and Léna 1986; Beckers et al. 1986) imaging. Those were stimulated by the coming new generation of very large telescopes of diameter D around 8 m (Barr 1986) and by the availability of AO components developed by defense programs (see for instance: Hardy et al. 1977; Pearson 1979; Gaffard et al. 1984; Fontanella 1985; Parenti 1988). Initiated by P. Léna, F. Merkle, and J.-C. Fontanella on the basis of the existing competences in France and at the European Southern Observatory (ESO), the COME-ON project was started in 1986 with the aim of demonstrating the performance of AO for astronomy. The consortium in charge of the project was initially made of three French laboratories associated with ESO, COME-ON standing for: CGE, a French company now CILAS (formerly LASERDOT), Observatoire de Paris-Meudon, ESO and ONERA. The purpose of the project was initially to build an AO-prototype system based on the available technologies and test it at an astronomical site, in order to gather experience for the ESO Very Large Telescope (VLT) program, including multi-telescope interferometry with the VLT interferometer (VLTI). The main requirement was to achieve nearly diffraction-limited imaging at the focus of a 4-m class telescope at near IR wavelengths from 2 to 5 μm, depending on the seeing conditions.
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