Elena Masciadri

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Statistical analysis of stellar scintillation on the pupil of a telescope, known as the scidar (scintillation, detection, and ranging) technique, is sensitive only to atmospheric turbulence at altitudes higher than a few kilometers. With the generalized scidar technique, recently proposed and tested under laboratory conditions, one can overcome this(More)
We report on a survey devoted for the search of exo-planets around young and nearby stars carried out with NACO at the VLT. The detection limit for 28 among the best available targets vs. the angular separation from the star is presented. The non-detection of any planetary mass companion in our survey is used to derive, for the first time, the frequency of(More)
The commonality of collisionally replenished debris around main-sequence stars suggests that minor bodies are frequent around Sun-like stars. Whether or not debris disks in general are accompanied by planets is yet unknown, but debris disks with large inner cavities—perhaps dynamically cleared—are considered to be prime candidates for hosting(More)
We propose an optical technique that allows us to estimate the inner scale by measuring the variance of angle of arrival fluctuations of collimated laser beams of different sections w (i) passing through a turbulent layer. To test the potential efficiency of the system, we made measurements on a turbulent air flow generated in the laboratory, the(More)
First evidences of IR excess and disk mass accretion (strong Hα emission) around brown dwarfs seem to indicate the existence of circumstellar disks around these sub-stellar objects. Nothing is known at the present time about outflows which potentially might be launched from brown dwarfs, although jets are typically associated with the accretion in standard(More)
These last years ground-based astronomy has been looking towards Antarctica, especially its summits and the internal continental plateau where the optical turbulence appears to be confined in a shallow layer close to the icy surface. Preliminary measurements have so far indicated pretty good value for the seeing above 30-35 m: 0.36” (Agabi et al. 2006),(More)
We present the results of a survey of 45 young (.250 Myr), close (.50 pc) stars with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT for the direct detection of extrasolar planets. As part of the survey, we observed 54 objects total, of which 45 were close, young stars, 2 were somewhat more distant (<150 pc), very young (≤10(More)
We present the results of monitoring optical-turbulence profiles at San Pedro Mártir, Mexico, during 11 nights in 1997 March and April, and 16 nights in 2000 May. The data were collected using the generalized scintillation detection and ranging (SCIDAR) technique from Nice University at the 1.5 and 2.1 m telescopes. A total of 6414 turbulence profiles were(More)
The active K2V star ǫ Eri hosts the most nearby known extrasolar planet. With an angular separation of about 1” on average, and an age of a few to several hundred Myrs, ǫ Eri b is one of the prime candidates for becoming the first definitive extrasolar planet imaged directly. We present a multi-epoch deep Max-Planck-Institut für Astronomie, Königstuhl 17,(More)
The giant jets represent a fundamental trace of the historical evolution of the outflow activity over timescales of ∼ 10 yr, i.e. a timescale comparable to the accretion time of the outflow sources in their main protostellar phase. The study of such huge jets provides the possibility of retrieving important elements related to the life of the outflow(More)