Final Report Summary - SPECULOOS (SPECULOOS: searching for habitable planets amenable for biosignatures detection around the nearest ultra-cool stars)
In fact, SPECULOOS started back in 2011 as a prototype mini-survey on the 60cm TRAPPIST robotic telescope with a target list composed of the 50 brightest southern ultracool dwarf stars. The goal of this prototype was to assess the feasibility of SPECULOOS, but it did much better than expected. Indeed, it detected around one of its targets, TRAPPIST-1, an amazing planetary system composed of seven Earth-sized planets in temperate orbits of 1.5 to 19 days. At least three of these planets orbit within the habitable zone of the star, and all of them are particularly well-suited for a detailed atmospheric study with JWST. Thanks to the resonant and transiting configuration of the system, the masses and radii of the planets could be very precisely measured. The detection of TRAPPIST-1 out of a target list of only 50 objects suggest that compact systems of rocky planets could be very frequent around ultracool dwarf stars, in agreement with recent theoretical predictions. If this is the case, then SPECULOOS should find many other similar systems, to eventually produce a catalogue of several dozens temperate rocky planets well-suited for detailed atmospheric characterization with next-generation major astronomical facilities.