Kepler-33 and Its Five Planets

Kepler-33 is a star located 3940 light-years away. It is 4.27 billion years old, has a mass of 1.29 solar masses, and a radius of 1.82 solar radii. Its reported mass and radius estimates are larger than the Sun’s, and its temperature of 5900 K is hotter than the Sun’s. Five planets are known to orbit this host.

All five planets were discovered by transit in 2011. Kepler-33 b is a Super-Earth with a radius of 1.74 Earth radii and an orbital period of 5.67 days. Kepler-33 c is Neptune-like, with a radius of 3.2 Earth radii and an orbital period of 13.2 days. Kepler-33 d is Jupiter-like, with a radius of 5.35 Earth radii and an orbital period of 21.8 days. Kepler-33 e is also Jupiter-like, with a radius of 4.02 Earth radii and an orbital period of 31.8 days. Kepler-33 f is likewise Jupiter-like, with a radius of 4.46 Earth radii and an orbital period of 41 days.

Each planet’s reported radius estimate is larger than Earth’s. Among the listed planets, Kepler-33 b has the shortest year by reported estimates and the smallest radius. Kepler-33 f has the longest year and the second-largest radius. Kepler-33 c has the second-shortest year and the second-smallest radius, while Kepler-33 d has the largest radius. Kepler-33 e has the second-longest year by reported estimates.