NIRPS eyes up to unveil exoplanets’ atmospheres

The new high-resolution Near-InfraRed Planet Searcher (NIRPS, Bouchy et al., 2017) is now fully operational at the ESO 3.6-m telescope in La Silla, Chile. This ultra-stable, ground-based spectrograph is designed to work in parallel with HARPS (Mayor et al., 2003) to extend the wavelength coverage from optical to Y, J and H bands and to reach high-precision radial velocities (RVs, 1 m/s) thanks to an avantgarde adaptive optics equipment. The Guaranteed Time Observations consist in (i) a blind RV survey of M dwarfs to determine the diversity of systems and find the best candidates for future characterisation, (ii) the measurement of masses and densities of known transiting planetary candidates around M stars, and (iii) an in-depth survey to characterise atmospheres of transiting exoplanets through high-fidelity transmission and emission spectroscopy. Contemporaneous to the JWST (Beichman et al., 2014) transit, eclipse, and phase curve observations, the NIRPS atmospheric survey leverages on high spectral resolution (~80,000) to resolve the shape and dynamics of atomic and molecular near-infrared signatures, enabling new insights on the climate, structure, layering, and escape processes in the atmospheres of exoplanets. In this talk, I will present the first NIRPS transit spectra of three ultra-hot Jupiters (WASP-189b, WASP-178b, and WASP-121b), which host some of the most extreme atmospheres known to date (Vaulato et al., in preparation). These exoplanets feature a bonanza of physical effects that have been previously uncovered via UV and optical observations and these recent NIRPS observations and early results open a new window to learn unprecedented insights into their properties.