The planetary system of Proxima Centauri seen with ESPRESSO

During last decade there have been a tremendous increase in detection and characterization of low-mass exoplanets, reaching the Earth size and mass domain, in particular those orbiting M dwarf stars, due to their smaller sizes and masses, resulting in planet larger transit amplitude and radial velocity signals. Extremely precise instruments such as the ESPRESSO spectrograph are designed to detect Earth-like planets, requiring in addition a detailed modeling of the stellar activity.

ESPRESSO is an ultra-stable high-resolution spectrograph, designed and developed involving institutions from Switzerland, Italy, Portugal, Spain, and ESO, which is located in the combined Coudé Lab of the VLT at ESO, and is able to operate either using one 8.2m-VLT UT or simultaneously with the four VLT UTs. ESPRESSO started routine operations in October 2018 at ESO, and is designed to achieve a radial velocity precision of 10 cm/s, thus opening the possibility to explore new frontiers in science such as the search for rocky planets and the measurement of the variation of physical constants (Pepe et al. 2021). ESPRESSO is considered a precursor of the ultra-stable high-resolution spectrograph ANDES (formerly known as HIRES) for the 39m-ELT telescope (Marconi et al. 2021).

ESPRESSO has been very successful so far in detecting and characterizing low-mass planets demonstrating the sub-m/s capabilities of the instrument, providing a unique ground-based facility with great synergy with exoplanet dedicated satellites such as Kepler (Toledo Padrón et al. 2020), TESS (Demangeon et al. 2021) and CHEOPS (Leleu et al. 2021). One of the most relevant recent achievement of ESPRESSO is the confirmation of the 11.2d Earth mass planet Proxima b in the habitable zone of Proxima Centauri, previously reported in Anglada-Escudé et al. (2016), and the discovery of the sub-Earth mass planet Proxima d in  a 5.1d orbit with a semiamplitude velocity of 40 cm/s together with a simultaneous, precise characterization of the activity of the star (Suárez Mascareño et al. 2020; Faria et al. 2022). This discovery together with the 5yr period super-Earth planet candidate Proxima c reported in Damasso et al. (2020) composes the currently known planetary system in the nearest stellar neighbour to our Sun, encouraging new detail studies of this star with current and future facilities such as ANDES@ELT. In this talk I will briefly summarize the main features of ESPRESSO performance focusing on revealing the planetary system around Proxima Centauri and future prospects.