WASP-139 b: A Jupiter-Like Planet in a Two-Star System

WASP-139 is a K0 star 693 light-years from Earth. Its reported mass is 0.92 solar masses, its reported radius is 0.8 solar radii, and its reported temperature is 5310 K, cooler than the Sun's. Its age carries a reported lower limit of 0.5 billion years. The star's reported radius estimate is smaller than the Sun's. One planet is known to orbit this host.

That planet, WASP-139 b, was discovered in 2016 by the transit method, which detects the small dip in a star's observed brightness when a planet passes in front of it. Classified as Jupiter-like, WASP-139 b has a reported radius of 8.97 Earth radii, larger than Earth's, and a reported mass of 37.2 Earth masses, also larger than Earth's. Its orbital period is 5.92 days. Its mean density is 0.284 g/cm³, 0.0516 times Earth's.