MICELA, GiuseppinaGiuseppinaMICELA2020-05-122020-05-1220150922-6435http://hdl.handle.net/20.500.12386/24712Stellar activity is the major astrophysical limiting factor for the study of planetary atmospheres. Its variability and spectral characteristics may affect the extraction of the planetary signal even for moderately active stars. A technique based on spectral change in the visible band was developed to estimate the effects in the infrared due to star activity. This method has been purposely developed for the EChO mission which had the crucial characteristics of monitoring simultaneously a broadband from visible to infrared. Thanks to this capability the optical spectrum, whose variations are mainly due to stellar activity, has been used as in an instantaneous calibrator to correct the infrared spectrum. The technique is based on principal component analysis which significantly reduces the dimensionality of the spectra. The method was tested on a set of simulations with realistic photon noise. It can be generalized to any chromatic variability effects provided that optical and infrared variations are correlated. <P />STAMPAenArticle10.1007/s10686-014-9430-12-s2.0-84952982844000367627900021https://link.springer.com/article/10.1007%2Fs10686-014-9430-12015ExA....40..723MFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation