TOI-1260: A Nearby K-Type Dwarf with Three Transiting Planets

TOI-1260 is a K6 V star, a main-sequence dwarf, located 240 light-years away. Its reported mass is 0.66 solar masses, its radius is 0.65 solar radii and its temperature is 4230 K, all of which are smaller or cooler than the Sun's corresponding values.

Three planets are known to orbit this host. TOI-1260 b is a Super-Earth discovered by transit in 2021, with a mass of 8.56 Earth masses, a radius of 2.41 Earth radii and an orbital period of 3.13 days. TOI-1260 c, a Neptune-like planet also found by transit in 2021, has a mass of 13.2 Earth masses, a radius of 2.76 Earth radii and an orbital period of 7.49 days. TOI-1260 d, likewise Neptune-like, was detected by transit in 2022 and has a mass of 11.8 Earth masses, a radius of 3.12 Earth radii and an orbital period of 16.6 days. Since a transit occurs when a planet crosses in front of its star from our viewpoint, causing a small dip in observed brightness, repeated dips are what establish these orbital periods.

All three planets are larger and more massive than Earth. Their estimated mean densities are 3.37 g/cm³ for TOI-1260 b, 3.46 g/cm³ for TOI-1260 c and 2.15 g/cm³ for TOI-1260 d. Among the listed planets, TOI-1260 b has the shortest year by reported estimates at 3.13 days and the smallest radius at 2.41 Earth radii, while TOI-1260 c has the second-shortest year at 7.49 days, the second-smallest radius at 2.76 Earth radii and the largest reported mass at 13.2 Earth masses. TOI-1260 d has the longest year at 16.6 days, the largest radius at 3.12 Earth radii and the second-smallest reported mass at 11.8 Earth masses.