KOI-351 and Its Eight Worlds

KOI-351 is a star 2770 light-years away with a mass of 1.12 solar masses, a radius of 1.25 solar radii, and a temperature of 6030 K. Its mass and radius are larger than the Sun's, and its temperature is hotter than the Sun's. Eight planets are known to orbit it, all discovered by transit, the dimming of starlight as a planet crosses the star's face.

The two planets with the shortest orbital periods are Earth-like in size. KOI-351 b orbits every 7.01 days with a radius of 1.31 Earth radii, and KOI-351 c orbits every 8.72 days with a radius of 1.19 Earth radii. Both are larger than Earth, and among the listed planets b has the shortest year while c has the second-shortest. Kepler-90 i, also Earth-like, orbits every 14.4 days with a radius of 1.32 Earth radii, larger than Earth's.

Three Neptune-like planets follow. KOI-351 d orbits every 59.7 days with a radius of 2.87 Earth radii, KOI-351 e every 91.9 days with a radius of 2.66 Earth radii, and KOI-351 f every 125 days with a radius of 2.88 Earth radii. Each is larger than Earth.

The two planets with measured masses are among those with the longest orbital periods. KOI-351 g, with a mass of 15 Earth masses, orbits every 211 days, and KOI-351 h, with a mass of 203 Earth masses, orbits every 332 days. Both are more massive than Earth, and h has the longest year among the listed planets while g has the second-longest.