Kepler-403: A Distant Star With Three Known Planets

Kepler-403 is a star located 2740 light-years away, and three planets have been identified orbiting it. The star is estimated to be 3.09 billion years old, with a mass of 1.25 solar masses, a radius of 1.45 solar radii, and a temperature of 6210 K. Its reported mass and radius estimates are larger than the Sun's, and its reported temperature is hotter than the Sun's.

All three planets were found by the transit method, in which a planet passes in front of its star from our viewpoint and causes a small dip in observed brightness; repeated dips help establish orbital periods. Kepler-403 b, classified as Earth-like, was discovered in 2014 and has an orbital period of 7.03 days and a radius of 1.25 Earth radii. Kepler-403 c, a Super-Earth discovered in 2014, has an orbital period of 54.3 days and a radius of 1.75 Earth radii. Kepler-403 d, also Earth-like, was discovered in 2016 and has an orbital period of 13.6 days and a radius of 1.42 Earth radii. The reported radius estimates of all three planets are larger than Earth's.

Among the listed planets, Kepler-403 b has the shortest year by reported estimates, at 7.03 days, and the smallest radius by reported estimates, at 1.25 Earth radii. Kepler-403 d has the second-shortest year, at 13.6 days, and the second-smallest radius, at 1.42 Earth radii. Kepler-403 c has the longest year, at 54.3 days, and the largest radius, at 1.75 Earth radii.