RISTRETTO: a pathfinder instrument for exoplanet atmosphere characterization

TL;DR

The paper introduces RISTRETTO, a new high-contrast, high-resolution spectrograph for ESO VLT designed to detect and characterize exoplanet atmospheres, especially Proxima b, using reflected light.

Contribution

It presents the design and requirements of RISTRETTO, an innovative instrument for exoplanet atmosphere characterization via high-contrast spectroscopy.

Findings

Design specifications for RISTRETTO are outlined.

The instrument aims to detect exoplanets in reflected light.

Preliminary design and requirements are discussed.

Abstract

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.