TOI-1736: A Distant Star with Two Known Worlds

TOI-1736 is a star located 290 light-years from Earth, and two planets have been detected in orbit around it. The host star is 9.2 billion years old and contains 1.04 solar masses of material. Its radius is 1.43 solar radii, so it is larger than the Sun, and its temperature of 5640 K makes it cooler than the Sun.

The first planet, TOI-1736 b, was discovered in 2023 by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it. Classified as Neptune-like, this planet has a radius of 3.18 Earth radii, larger than Earth's, and a mass of 12.3 Earth masses, also greater than Earth's. Its mean density is 2.1 g/cm³, 0.382 times Earth's. TOI-1736 b completes one orbit in 7.07 days, the shortest year among the listed planets.

TOI-1736 c was also announced in 2023, but it was found through the radial velocity method, which measures the wobble a planet's gravity induces in its star. This planet has a minimum mass of 2440 Earth masses, meaning its true mass is at least that value, and this lower bound is larger than Earth's. In fact, the minimum mass is roughly 7.68 times Jupiter's mass. TOI-1736 c takes 571 days to complete one orbit, the longest year among the listed planets.