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The SPECULOOS project aims to detect terrestrial exoplanets well suited for detailed atmospheric characterization, explains Principal Investigator Michaël Gillon.

Simultaneous observations of TRAPPIST-1 b from JWST at 12.8 and 15 μm indicate that it is probably a bare rock with a mineral-rich surface. However, an alternative scenario with a CO₂-rich atmosphere and hazes could also explain the observations.

The SPECULOOS project detected an Earth-sized planet in a short orbit around a nearby Jupiter-sized star. This planet, SPECULOOS-3 b, is one of the most promising rocky exoplanets for detailed emission spectroscopy characterization with JWST.

Last year, three Earth-sized planets were discovered to be orbiting the nearby Jupiter-sized star TRAPPIST-1; now, follow-up photometric observations from the ground and from space show that there are at least seven Earth-sized planets in this star system, and that they might be the right temperature to harbour liquid water on their surfaces.

Analysis of data from multiple instruments reveals a giant exoplanet in orbit around the 0.2-solar-mass star TOI-6894. The existence of this exoplanetary system challenges assumptions about planet formation and it is an excellent target for atmospheric characterization.

The authors find that a nearby planetary system has two terrestrial planets that transit in front of their star (from our perspective). Transiting terrestrial planets are sought after, as they can be characterized in detail, including their atmospheres. Having two in the same system is very rare.

Precise mass and radius measurements of giant planet WASP-193 b find an extremely low density of 0.059 ± 0.014 g cm⁻³. Current evolutionary models cannot fully explain such a low density, but the extended atmosphere makes WASP-193 b very suitable for high-precision characterization via JWST.

The authors report on a temperate Earth-sized planet orbiting the cool M6 dwarf LP 791-18 with a radius of 1.03 ± 0.04 R_⊕ and an equilibrium temperature of 300–400 K, with the permanent night side plausibly allowing for water condensation.

Combining the infrared capabilities of JWST and synthetic tracking techniques, the detection of some of the smallest asteroids ever observed in the main belt is reported; their large abundance reveals a population driven by collisional cascade.

Hubble observations of the TRAPPIST-1 system exclude the presence of H₂-dominated cloud-free atmospheres for the three planets within or around the system’s habitable zone. This result supports the hypothesis that these planets are terrestrial in nature.

The radial-velocity technique could detect a small gas giant orbiting a binary star and determine its mass: 65.2 ± 11.8 Earth masses. The system also hosts a smaller inner planet, making it one of the few known multiplanetary circumbinary systems.

The detection of thermal emission from the rocky exoplanet TRAPPIST-1 c using the Mid-Infrared Instrument on the James Webb Space Telescope reveals a dayside brightness temperature that disfavours a thick, CO₂-rich atmosphere.

The Transiting Exoplanet Survey Satellite (TESS) has identified a nearby, bright, quiescent M dwarf star that hosts two sub-Neptune-sized planets and one super-Earth-sized planet. The system is eminently suitable for follow-up studies of transit timing variations, radial velocity measurements and transmission spectroscopy.

Pseudomonas aeruginosa employs lectins to bind to its host cells, and is known to be the major cause of lung infections. Lectin B (LecB) from Pseudomonas aeruginosa binds specifically to galactose and fucose and is important for pathogenicity, adhesion and biofilm formation. In this work, the neutron crystal structure (1.9 Å) of the deuterated LecB/Ca/fucose complex is reported. The structure, in combination with perdeuteration of the ligand and the receptor allowed the observation of hydrogen atoms, protonation states and hydrogen bonds involved in the interaction between pathogenic bacteria and host cells. Thus the study provides structural insights into the mechanism of high affinity binding of LecB to its targets.

Three Earth-sized planets—receiving similar irradiation to Venus and Earth, and ideally suited for atmospheric study—have been found transiting a nearby ultracool dwarf star that has a mass of only eight per cent of that of the Sun.

Three planets orbit the Sun-like star ν² Lupi. CHEOPS data show that all of them are transiting and show remarkable diversity. In particular, dry and gas-poor inner planet b has experienced extensive atmospheric loss, while planets c and d are water rich and have a small gaseous envelope of primordial origin.

Orbital parameters for the seventh Earth-sized transiting planet around star TRAPPIST-1 are reported, along with an investigation into the complex three-body resonances linking every member of this planetary system.

The resonant chain of the TRAPPIST-1 planets is dynamically fragile, as small perturbations during its lifetime would have disrupted it. N-body simulations show that the system could not have interacted with more than 0.05 Earth masses of material after its formation. Thus, any water in the planets must come from the planets’ original accretion.

2M1510 is an approximately 45-million-year-old triple system of brown dwarfs, two of which form a close binary in a 20-day orbit and have almost the same mass (3.82% and 3.75% of the mass of the Sun, respectively). Their physical parameters are in good agreement with evolutionary models except for luminosity, suggesting that we might be underestimating the masses of brown dwarfs and massive exoplanets by about 30%.

A low-mass star that is just 12 parsecs away from Earth is shown to be transited by an Earth-sized planet, GJ 1132b, which probably has a rock/iron composition and might support a substantial atmosphere.

A longitudinal thermal brightness map of the super-Earth exoplanet 55 Cancri e reveals strong day–night temperature contrast, indicating inefficient heat redistribution consistent with 55 Cancri e either being devoid of atmosphere or having an optically thick atmosphere with heat recirculation confined to the planetary dayside.

The JWST has the potential to increase our understanding of terrestrial exoplanets and their atmospheres, but the various signal contaminations need to be isolated and quantified. Using JWST Cycle 1 observations of TRAPPIST-1 as a benchmark, this Perspective proposes a series of steps to use future JWST data efficiently for this purpose.