RISTRETTO: high-resolution spectroscopy at the diffraction limit of the VLT

Christophe Lovis, Nicolas Blind, Bruno Chazelas, Jonas G. Kühn, Ludovic Genolet, Ian Hughes, Michaël Sordet, Robin Schnell, Martin Turbet, Thierry Fusco, Jean François Sauvage, Maddalena Bugatti, Nicolas Billot, Janis Hagelberg, Eddy Hocini, Olivier Guyon

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


RISTRETTO is a visible high-resolution spectrograph fed by an extreme adaptive optics (XAO) system, to be proposed as a visitor instrument on ESO VLT. The main science goal of RISTRETTO is the detection and atmospheric characterization of exoplanets in reflected light, in particular the temperate rocky planet Proxima b. RISTRETTO will be able to measure albedos and detect atmospheric features in a number of exoplanets orbiting nearby stars for the first time. It will do so by combining a high-contrast AO system working at the diffraction limit of the telescope to a high-resolution spectrograph, via a 7-spaxel integral-field unit (IFU) feeding single-mode fibers. Further science cases for RISTRETTO include the study of accreting protoplanets such as PDS 70 b & c through spectrally-resolved Hα emission; and spatially-resolved studies of Solar System objects such as icy moons and the ice giants Uranus and Neptune. The project is in an advanced design phase for the spectrograph and IFU/fiber-link sub-systems, and a preliminary design phase for the AO front-end. Construction of the spectrograph and IFU/fiber-link will start at the end of 2022. RISTRETTO is a pathfinder instrument in view of similar developments at ESO ELT, in particular the SCAO-IFU mode of ELT-ANDES and the future ELT-PCS instrument.

Original languageEnglish (US)
Title of host publicationGround-based and Airborne Instrumentation for Astronomy IX
EditorsChristopher J. Evans, Julia J. Bryant, Kentaro Motohara
ISBN (Electronic)9781510653498
StatePublished - 2022
EventGround-based and Airborne Instrumentation for Astronomy IX 2022 - Montreal, Canada
Duration: Jul 17 2022Jul 22 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceGround-based and Airborne Instrumentation for Astronomy IX 2022


  • Exoplanets
  • H-alpha emission
  • Proxima b
  • XAO
  • biosignatures
  • high contrast
  • high-resolution spectroscopy
  • reflected light

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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