The characterization of exoplanetary atmospheres is one of the most active research fields in modern astrophysics, made possible by the development of dedicated instruments and techniques. The basic idea of this research is quite simple: obtaining spectroscopic observations of stars with planets during the transit of the planet in front of its star, which is the moment when part of
Most of the exoplanets identified so far have been discovered by using two techniques: transits and radial velocity. In particular, radial velocity method consists in detecting the oscillations of stars around the center of mass common with their planetary systems by measuring periodic doppler shifts in high-resolution spectra. The main difficulty with this technique is the fact that stellar activity,
