Kepler-553: A Distant Star With Two Giant Worlds

Kepler-553 is a star located 2380 light-years away, and two planets have been found orbiting it. The star is estimated to be 8.8 billion years old, with a mass of 0.889 solar masses and a radius of 0.902 solar radii. Its reported temperature is 5190 K. The star's reported mass and radius estimates are smaller than the Sun's, and its reported temperature is cooler than the Sun's.

Both planets were discovered by the transit method in 2016, which detects the small dip in a star's brightness when a planet crosses in front of it from our viewpoint. Repeated dips help establish orbital periods, the time each planet takes to complete one orbit.

Kepler-553 b is classified as Jupiter-like, meaning its radius exceeds four times Earth's. Its reported radius estimate is 4.74 Earth radii, and its mass has a reported upper limit of 116.00736855 Earth masses. It completes an orbit in 4.03 days. Among the listed planets, Kepler-553 b has the shortest year by reported estimates and the smallest radius by reported estimates.

Kepler-553 c is also Jupiter-like. Its reported radius estimate is 11.6 Earth radii, larger than Earth's, and its reported mass estimate is 2130 Earth masses, also larger than Earth's. That mass is roughly 6.7 times Jupiter's mass, and the planet's mean density is 7.56 g/cm³, 1.37 times Earth's. It orbits once every 328 days. Among the listed planets, Kepler-553 c has the longest year by reported estimates and the largest radius by reported estimates.