HD 143811 A and Its Circumbinary Planet

HD 143811 A is a star 446 light-years away with a reported mass of 1.3 solar masses, a radius of 1.68 solar radii, and a temperature of 6430 K. All three measurements exceed the Sun's corresponding values. One planet is known to orbit this host.

That planet, HD 143811 AB b, is a Jupiter-like world, a class that exceeds 4 times Earth's radius. It was discovered by imaging in 2025. Its radius is 15.7 Earth radii, larger than Earth's. Its mass is 1940 Earth masses, also larger than Earth's and roughly 6.1 times Jupiter's mass. It completes an orbit in 117000 days, and its mean density is 2.76 g/cm³, 0.502 times Earth's. As a circumbinary planet, it orbits both stars of the binary system rather than one star alone.