TOI-257 is a star with 1.41 times the mass of the Sun, and 1.87 times its radius. It is located 250.82 light years away from the solar system.
TOI-257 is known to have 1 exoplanets in orbit around it.
TOI-257 b was discovered by the Transiting Exoplanet Survey Satellite (TESS) observatory, in 2021-04, using the transit method. Its semi-major axis is 0.15 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of TOI-257 b is 43.884 times the mass of Earth. The radius of TOI-257 b is 7.163 that of Earth. At more than 10 Earth masses, TOI-257 b is an ice giant, a planet that is made up mostly of volatiles like water, amonia and methane, and enveloped by a dense hydrogen and helium atmosphere, much like Uranus and Neptune in our solar system.