Abstract We present the detection and validation of a small, temperate transiting exoplanet orbiting TOI-1080 every 3. 9652482-₀. ₀₀₀₀₀₁₅^+0. 0000014 days. The host is a quiet M4V star at 25. 6 pc. The planet signal was first detected by TESS and validated using TESS and ground-based observations. By fitting the available light curves, the planet radius is measured to be 1. 200 ± 0. 058R⊕ and its equilibrium temperature of 368-₁₀. ^+12 K. With NIRPS radial velocities, we are able to place a 3-σ upper limit on the mass of TOI-1080 b of 10. 7 M⊕. Our injection-recovery tests enable us to discard additional transiting planets in the TOI-1080 system with radii down to 0. 9 R⊕ and periods between 0. 5 and 7. 7 days, and planets with radii larger than 1. 4 R⊕ for periods up to 19 days. We demonstrate that it is highly amenable to characterisation of its mass and putative atmosphere. In particular, we find that TOI-1080 b is an exceptional target for the ongoing JWST+HST Rocky Worlds DDT programme, having a priority score that is higher than four out of nine targets currently being investigated by the programme. TOI-1080 b can be added to the sample of nearby benchmark planets accessible for detailed study with JWST.
Chew et al. (Wed,) studied this question.