TOI-778: A Planet Around an F-Type Star

TOI-778 is a star 528 light-years away with one known planet in orbit around it. The star is a main-sequence dwarf of spectral type F3 V, and its age is 1.95 billion years. It has a mass of 1.4 solar masses and a radius of 1.71 solar radii, and its temperature is 6640 K. The star's reported mass estimate is larger than the Sun's, its reported radius estimate is larger than the Sun's, and its reported temperature is hotter than the Sun's.

The single planet, TOI-778 b, is a Jupiter-like world, a size class that denotes a radius exceeding four times Earth's. It was discovered by the transit method, in which a planet passing in front of its star briefly dims the observed brightness, and repeated dips help establish the orbital period, which was announced in 2023. That period is 4.63 days. TOI-778 b has a radius of 15.4 Earth radii and a mass of 878 Earth masses, both larger than Earth's corresponding values. Its mass is roughly 2.76 times Jupiter's mass, and its mean density is 1.32 g/cm³, 0.24 times Earth's.