References of "Mawet, Dimitri"
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See detailCoronagraphic imaging of three weak-line T Tauri stars: evidence of planetary formation around PDS 70
Riaud, Pierre ULg; Mawet, Dimitri ULg; Absil, Olivier ULg et al

in Astronomy and Astrophysics (2006), 458

Context: High angular resolution imaging of nearby pre-main sequence stars with ages between 1 and 30 Myr can give valuable information on planet formation mechanisms. This range of ages is thought to ... [more ▼]

Context: High angular resolution imaging of nearby pre-main sequence stars with ages between 1 and 30 Myr can give valuable information on planet formation mechanisms. This range of ages is thought to correspond to the dissipation of the optically thick dust disks surrounding young stars and to the end of the planet formation. Aims: This paper presents new observations of three weak-line T Tauri Stars (WTTS) of intermediate ages ranging from 7 to 16 Myr. It aims at increasing the knowledge and sample of circumstellar disks around "old" WTTS. Methods: We observed three stars with the VLT's NAOS-CONICA adaptive optics system in coronagraphic mode. The four-quadrant phase mask coronagraph was used to improve the dynamic range (by a factor of 100) while preserving the high angular resolution (inner working angle of 0farcs 15). Results: One object of our sample (PDS 70), a K5 star, exhibits a brown dwarf companion and a disk in scattered light with a surface brightness power law of r[SUP]-2.8[/SUP], extending from a distance of 14 to 140 AU (assuming a stellar distance of 140 pc) and an integrated luminosity of 16.7 mJy in the K_s-band. The mass of the companion can be estimated to be within a range between 27 and 50 Jupiter masses with an effective temperature of 2750 ± 100 K. This object also shows a resolved outflow stretching up to 550 AU. Conclusions: This newly detected circumstellar disk shows strong similarities with the disk around TW Hya, and adds to the observed population of "old" TTS surrounded by circumstellar material. Moreover, three clues of planetary formation are brought to light by this study. [less ▲]

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See detailThe 4m international liquid mirror telescope (ILMT)
Surdej, Jean ULg; Absil, Olivier ULg; Bartczak, Przemyslaw ULg et al

in Stepp, Larry (Ed.) Ground-based and Airborne Telescopes (2006, July 01)

The entire funding has recently been obtained in Belgium for the construction of a 4m Liquid Mirror Telescope. Its prime focus will be equipped with a semi-conventional glass corrector allowing to correct ... [more ▼]

The entire funding has recently been obtained in Belgium for the construction of a 4m Liquid Mirror Telescope. Its prime focus will be equipped with a semi-conventional glass corrector allowing to correct for the TDI effect and a thinned, high quantum efficiency, 4K × 4K pixel equivalent CCD camera. It will be capable of subarcsecond imaging in the i'(760 nm) and possibly r', g' band(s) over a field of ~ 30' in diameter. This facility will be entirely dedicated to a deep photometric and astrometric variability survey over a period of ~ 5 years. In this paper, the working principle of liquid mirror telescopes is first recalled, along with the advantages and disadvantages of the latter over classical telescopes. Several science cases are described. For a good access to one of the galactic poles, the best image quality sites for the ILMT are located either in Northern Chile (latitude near -29°30') or in North-East India (Nainital Hills, latitude near +29°30'). At those geographic latitudes, a deep (i' = 22.5 mag.) survey will approximately cover 90 square degrees at high galactic latitude, which is very useful for gravitational lensing studies as well as for the identification of various classes of interesting galactic and extragalactic objects (cf. microlensed stars, supernovae, clusters, etc.). A description of the telescope, its instrumentation and the handling of the data is also presented. [less ▲]

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See detailAchromatic optical vortex coronagraph with subwavelength gratings
Mawet, Dimitri ULg; Riaud, Pierre ULg; Baudrand, J. et al

in Proceedings of the Coronagraph Workshop (2006)

Detailed reference viewed: 21 (4 ULg)