TOI-451 and Its Three Known Planets

TOI-451 is a G8 V star located 404 light-years away. This spectral type marks it as a G-type main-sequence dwarf, a category that includes the Sun. The star's age is 0.125 billion years. Its mass is 0.93 solar masses and its radius is 0.85 solar radii, both smaller than the Sun's corresponding values, while its temperature of 5490 K is cooler than the Sun's.

Three planets have been reported around TOI-451, all discovered in 2020 by the transit method, in which a planet passing in front of its star produces a small dip in observed brightness. TOI-451 b is a Super-Earth with a mass of 4.7 Earth masses and a radius of 1.84 Earth radii, larger than Earth in both respects, and a mean density of 4.16 g/cm³, 0.754 times Earth's. Its orbital period is 1.86 days, the shortest among the listed planets.

TOI-451 c and TOI-451 d are both Neptune-like planets. TOI-451 c has a mass of 3.7 Earth masses, a radius of 2.93 Earth radii, and a mean density of 0.81 g/cm³, 0.147 times Earth's. Its orbital period is 9.19 days. TOI-451 d has a mass of 10.2 Earth masses, a radius of 3.93 Earth radii, and a mean density of 0.926 g/cm³, 0.168 times Earth's. Its orbital period is 16.4 days, the longest among the listed planets. Both planets are larger and more massive than Earth. Within this group, TOI-451 c has the smallest reported mass, TOI-451 d the largest reported mass and the largest radius, and TOI-451 b the smallest radius.