TOI-1758 and Its Neptune-Like Planet

TOI-1758 is a star 315 light-years away with a single known planet in its system. The host star is estimated to be 7.5 billion years old, with a mass of 0.825 solar masses and a radius of 0.816 solar radii. Its temperature is 5150 K, cooler than the Sun, and both its mass and radius estimates are smaller than the Sun's.

The one known planet, TOI-1758 b, was discovered by transit in 2024. A transit occurs when a planet passes in front of its star from our viewpoint, causing a small dip in observed brightness; repeated dips help establish orbital periods. TOI-1758 b orbits its star every 20.7 days and has a radius of 3.62 Earth radii, larger than Earth's. That radius places it in the Neptune-like size class, which includes planets reaching up to 4 times Earth's radius.