TOI-469: A Cool, Ancient Star With Three Known Planets

TOI-469 is a star 222 light-years away with three known planets. It is 11.7 billion years old, has 0.89 solar masses, 0.98 solar radii, and a temperature of 5290 K. Its mass is smaller than the Sun's, and its temperature is cooler than the Sun's.

The planets include two Super-Earths and one Neptune-like world. HIP 29442 c is a Super-Earth discovered in 2023 by radial velocity, with a mass of 4.5 Earth masses, a radius of 1.55 Earth radii, and an orbital period of 3.54 days. HIP 29442 d is also a Super-Earth found in 2023 by radial velocity, with a mass of 5.14 Earth masses, a radius of 1.54 Earth radii, and an orbital period of 6.43 days. TOI-469.01 is a Neptune-like planet discovered in 2021 by transit, with a mass of 9.1 Earth masses, a radius of 3.41 Earth radii, and an orbital period of 13.6 days.

Among the listed planets, HIP 29442 c has the shortest year, at 3.54 days. HIP 29442 d has the second-shortest year, at 6.43 days, and the smallest radius, at 1.54 Earth radii. TOI-469.01 has the longest year, at 13.6 days, and the largest radius, at 3.41 Earth radii.

Among the listed planets, HIP 29442 c has the smallest reported mass, at 4.5 Earth masses. HIP 29442 d has the second-smallest reported mass, at 5.14 Earth masses. TOI-469.01 has the largest reported mass, at 9.1 Earth masses.