Introduction

Ristretto project #

logo
Artist impression of the Proxima System (credit ESO)

RISTRETTO is an instrumental project to detect the reflected light of nearby exoplanets using the spectroscopic coronagraphy technique.

Once ready this instrument will be proposed as a visitor instrument for the ESO VLT/AOF facility.

In the first phase a single-mode high-resolution spectrograph with 7 spaxels will be built and tested on the Euler 1.2m telescope in La Silla with the KalAO adaptive optics system.

High-contrast imaging in the visible

In order to achieve its goal, the instrument needs a XAO system in the visible giving at the same time the highest possible Strehl (to efficiently couple to the single-mode fibers that feed the spectrograph) and a high raw contrast in order to be able to detect the planet light. The average target value for the contrast is 10-4.

High-resolution spectrograph

In order to achieve the required total contrast (in the 10-7 range) to detect the reflected light of the planet one will use a high-resolution spectrograph coupled to an integral-field unit in order to locate the planet. The additional gain in contrast is obtained thanks to the radial velocity difference between the planet and its host star.