Kepler-204 and Its Two Known Planets

Kepler-204 is a star located 2240 light-years away with two known planets. The host star is 5.75 billion years old and has a mass of 1.03 solar masses, a radius of 1.11 solar radii, and a temperature of 5870 K, which is hotter than the Sun's reported temperature.

Both planets were discovered by transit in 2014. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness; repeated dips help establish orbital periods. Kepler-204 b is a Neptune-like planet with an orbital period of 14.4 days and a radius of 2.53 Earth radii, larger than Earth's. Kepler-204 c is a Super-Earth with an orbital period of 25.7 days and a radius of 1.79 Earth radii, also larger than Earth's.

Among the listed planets, Kepler-204 b has the shortest year by reported estimates, at 14.4 days, and the largest radius by reported estimates, at 2.53 Earth radii. Kepler-204 c has the longest year by reported estimates, at 25.7 days, and the smallest radius by reported estimates, at 1.79 Earth radii. Planet size classes compare radius with Earth's: a Super-Earth reaches 2.5 times Earth's radius, while a Neptune-like planet reaches 4 times.