We introduce the RISTRETTO instrument for ESO VLT, an evolution from the original idea of connecting the SPHERE high-contrast facility to the ESPRESSO spectrograph (Lovis et al 2017). RISTRETTO is an independent, AO-fed spectrograph proposed as a visitor instrument, with the goal of detecting nearby exoplanets in reflected light for the first time. RISTRETTO aims at characterizing the atmospheres of Proxima b and several other exoplanets using the technique of high-contrast, high-resolution spectroscopy. The instrument is composed of two parts: a front-end to be installed on VLT UT4 providing a two-stage adaptive optics system using the AOF facility with coronagraphic capability and a 7-fiber IFU, and a diffraction-limited R=135,000 spectrograph in the 620-840 nm range. We present the requirements and the preliminary design of the instrument.
@article{arxiv.2012.08182,
title = {RISTRETTO: a pathfinder instrument for exoplanet atmosphere characterization},
author = {Bruno Chazelas and Christophe Lovis and Nicolas Blind and Jonas Kühn and Ludovic Genolet and Ian Hughes and Martin Turbet and Janis Hagelberg and Nathanaël Restori and Markus Kasper and Nelly Natalia Cerpa Urra},
journal= {arXiv preprint arXiv:2012.08182},
year = {2020}
}