Two studies in Astronomy & Astrophysics outline the instrumental developments and simulations underpinning Proxima b’s detectability and potential atmospheric signatures.

The RISTRETTO project at the University of Geneva has prototyped and tested core elements of a high-precision spectrograph designed to observe reflected light from Proxima b.

The instrument employs a coronagraphic integral field unit with hexagonal microlenses and optical fibers to suppress starlight and access the planet’s signal.

simulations suggest that with roughly 55 hours of VLT observations, Proxima b could be detected in reflected light, and about 85 hours could reveal atmospheric signatures such as oxygen or water.

An extreme adaptive optics system has been validated in tests, boosting image quality and contrast to separate Proxima b from its star.

Next steps include clean-room spectrograph testing, real observing tests with the Haute-Provence Observatory telescope, and finalizing the XAO design.

The project has secured Swatch funding to complete the instrument ahead of its planned 2030 installation on the Very Large Telescope.

RISTRETTO is envisioned as a pathfinder for second-generation ELT instruments, showcasing high-dispersion coronagraphy with extreme adaptive optics for studying nearby rocky exoplanets.