Comparison of methods for detection and characterization of exoplanets with SPHERE/IRDIS
Résumé
SPHERE is a second generation instrument for the Very Large Telescope (VLT) which will aim at directly detecting the intrinsic flux of young giant exoplanets thanks to a dedicated extreme adaptive optics system and coronagraphs. Exoplanet detection in the near-infrared will be performed in parallel with an integral field spectrograph and a differential imager, IRDIS. IRDIS main mode for exoplanet detection will be Dual- Band Imaging (DBI) where two images are acquired simultaneously at close wavelengths around expected sharp features in cold planetary objects spectra. We present here the end-to-end simulations performed to obtain realistic data for IRDIS in DBI mode with temporal evolution of the quasi-static speckle pattern. Data cubes have been generated to represent 4 hour observations in IRDIS filter pairs for various star magnitudes and planets at angular separations from 0."2 to 2".0. Using this unique set of data, we present a comparison of various data analysis methods for high-contrast imaging with IRDIS in DBI mode both in terms of detection limits and of estimation of the exoplanet flux after speckle noise attenuation.