Kepler-1666 and Its Two Neptune-Like Planets

Kepler-1666 is a star 4500 light-years away with two planets. The star has a mass of 1.08 solar masses, a radius of 1.03 solar radii, and a temperature of 6300 K, which is hotter than the Sun's reported temperature. Both planets were discovered in 2020 by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it.

Kepler-1666 b and Kepler-1666 c are both Neptune-like, a size class that reaches up to 4 times Earth's radius. Kepler-1666 b has a radius of 2.88 Earth radii and an orbital period of 25.8 days, while Kepler-1666 c has a radius of 3.24 Earth radii and an orbital period of 40.7 days. Both planets are larger than Earth by reported radius estimates. Among the listed planets, Kepler-1666 b has the shortest year and the smallest radius, while Kepler-1666 c has the longest year and the largest radius.