ESPRESSO on VLT: An Instrument for Exoplanet Research

ESPRESSO (Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations) is a VLT ultra-stable high resolution spectrograph installed at ESO’s Paranal Observatory in Chile at the end of 2017 and that started regular operations in October 2018. The spectrograph is located at the VLT Combined-Coudé Laboratory and is able to operate with one or (simultaneously) four 8.2 m Unit Telescopes (UTs) through four optical Coudé trains. Combining efficiency and extreme spectroscopic precision, ESPRESSO has demonstrated to gain about two magnitudes with respect to its predecessor HARPS. ESPRESSO has improved the instrumental radial-velocity precision getting close to the aimed 10 cm s−1 level, thus opening the possibility to explore new frontiers in the search for Earth-mass exoplanets in the habitable zone of quiet, nearby G to M-dwarfs. ESPRESSO will be certainly an important development step toward high-precision ultra-stable spectrographs on the next generation of giant telescopes such as the ELT.