HATS-31 b: A Jupiter-like World in a Close Orbit

HATS-31 is a star located 2520 light-years away, with a planetary system that includes one known planet. The star has a mass of 1.27 solar masses and a radius of 1.87 solar radii. It is 4.3 billion years old and has a temperature of 6050 K. Its mass, radius, and temperature are all larger than the Sun's, and its temperature is hotter than the Sun's.

The planet HATS-31 b is a Jupiter-like world, a classification based on its radius exceeding four times Earth's radius. It was discovered in 2016 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. HATS-31 b orbits its star every 3.38 days. Its radius is 18.4 Earth radii, and its mass is 280 Earth masses, both larger than Earth's corresponding values. Its mean density is 0.248 g/cm³, which is 0.045 times Earth's.