Kepler-1987: A Cool Dwarf and Its Four Small Worlds

Kepler-1987 is a star located 1,940 light-years away, and four planets have been found orbiting it. The star itself has a reported mass estimate of 0.778 solar masses, a radius estimate of 0.729 solar radii, and a temperature of 4,750 K. These values are all smaller or cooler than the corresponding solar values.

The four planets are Kepler-1987 b, c, d, and e, all discovered by transit in 2023. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness. The planets range in size from Earth-like to Neptune-like, and each has a reported radius larger than Earth's.

Kepler-1987 b is an Earth-like planet with an orbital period of 2.35 days and a radius of 1.23 Earth radii. Its year is the shortest among the listed planets, and its radius is the smallest. Kepler-1987 c is also Earth-like, with an orbital period of 3.65 days and a radius of 1.33 Earth radii. Among the listed planets, its year is the second-shortest and its radius is the second-smallest.

Kepler-1987 d is a Neptune-like planet with an orbital period of 5.64 days and a radius of 2.66 Earth radii. Its year is the second-longest among the listed planets, and its radius is the largest. Kepler-1987 e is a Super-Earth with an orbital period of 8.74 days and a radius of 1.92 Earth radii. Among the listed planets, its year is the longest and its radius is the second-largest.