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Last name: MAWET
First name: Dimitri
International audience
International audience
International audience
The detection and characterization of extrasolar planets with SPHERE (Spectro Polarimetric High contrast Exoplanet REsearch) is challenging and in particular relies on the ability of a coronagraph to attenuate the diffracted starlight. SPHERE includes 3 instruments, 2 of which can be operated simultaneously in the near IR from 0.95 to 1.8...
The close-in regions of bright quasars' host galaxies have been difficult to image due to the overwhelming light coming from quasars. With coronagraphic observations in visible light using the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope, we removed 3C 273 quasar light using color-matching reference stars. The...
Spectral shaping is critical to many fields of science. In astronomy for example, the detection of exoplanets via the Doppler effect hinges on the ability to calibrate a high resolution spectrograph. Laser frequency combs can be used for this, but the wildly varying intensity across the spectrum can make it impossible to optimally utilize the...
International audience
International audience
Context. Gaps in circumstellar disks can signal the existence of planetary perturbers, making such systems preferred targets for direct imaging observations of exoplanets. Aims: Being one of the brightest and closest stars to the Sun, the photometric standard star Vega hosts a two-belt debris disk structure. Together with the fact that its...
The low wind effect is a phenomenon disturbing the phase of the wavefront in the pupil of a large telescope obstructed by spiders, in the absence of wind. It can be explained by the radiative cooling of the spiders, creating air temperature inhomogeneities across the pupil. Because it is unseen by traditional adaptive optics (AO) systems, thus...
We aim to inform Astro2020 of the status of coronagraph technology for use with a space-based segmented and/or partially obscured primary mirror. Our design and modeling study has determined that multiple coronagraph architectures can achieve the necessary performance. Some preliminary observatory requirements appear challenging but achievable.
Instrumentation techniques in the field of direct imaging of exoplanets have greatly advanced over the last two decades. Two of the four NASA-commissioned large concept studies involve a high-contrast instrument for the imaging and spectral characterization of exo-Earths from space: LUVOIR and HabEx. This whitepaper describes the status of 8...