Exoplanet imaging by infrared interferometry: a new paradigm

The spectral characterisation and understanding of terrestrial exoplanets is currently one of the most ambitious and challenging long-term goals of astrophysics. All observing techniques with the potential to tackle this challenge face the same limitations: the overwhelmingly dominant flux of the host star and/or the lack of angular resolution. A very promising technical solution around these issues is nulling interferometry, which combines the advantages of stellar interferometry (high angular resolution) and coronagraphy (starlight rejection). Thanks to decades of research and investments by ESO, interferometry has now become sufficiently mature to enable the direct characterisation of exoplanets as showcased by new results from the GRAVITY instrument installed on the Very Large Telescope Interferometer (VLTI). In this talk, I will present a new project recently-funded by the European Research Council (ERC) to build and install the first VLTI instrument with nulling capabilities. By leveraging its state-of-the-art infrastructure, long baselines, and strategic position in the Southern hemisphere, the new VLTI instrument will be able to carry out several high-impact exoplanet programmes to characterise the chemical composition of Jupiter-like exoplanets at the most relevant angular separations (i.e., close to the snow line) and better understand how planets form and evolve. I will end this presentation with long-term prospects to search for biosignatures on the surface of rocky exoplanets with a similar instrument launched into space.