TOI-178 is a star with 0.65 times the mass of the Sun, and 0.65 times its radius. It is located 204.50 light years away from the solar system and is estimated to be 7.1 billion years old, as compared to the Sun which is roughly 4.6 billion years old.
TOI-178 is known to have 6 exoplanets in orbit around it.
TOI-178 b was discovered by the Transiting Exoplanet Survey Satellite (TESS) observatory, in 2021-01, using the transit method. Its semi-major axis is 0.03 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of TOI-178 b is 1.501 times the mass of Earth. The radius of TOI-178 b is 1.152 that of Earth. With a mass below 5 Earth masses, a density of 0.98, and a semi-major axis of 0.02607 astronomical units, TOI-178 b could, potentially, be an ocean world - a planet with no dry land.
TOI-178 c was discovered by the Transiting Exoplanet Survey Satellite (TESS) observatory, in 2021-01, using the transit method. Its semi-major axis is 0.04 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of TOI-178 c is 4.773 times the mass of Earth. The radius of TOI-178 c is 1.669 that of Earth. With a mass below 5 Earth masses, a density of 1.02, and a semi-major axis of 0.037 astronomical units, TOI-178 c could, potentially, be an ocean world - a planet with no dry land.
TOI-178 d was discovered by the Transiting Exoplanet Survey Satellite (TESS) observatory, in 2021-01, using the transit method. Its semi-major axis is 0.06 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of TOI-178 d is 3.011 times the mass of Earth. The radius of TOI-178 d is 2.572 that of Earth. With a mass below 5 Earth masses, a density of 0.177, and a semi-major axis of 0.0592 astronomical units, TOI-178 d could, potentially, be an ocean world - a planet with no dry land.
TOI-178 e was discovered by the Transiting Exoplanet Survey Satellite (TESS) observatory, in 2021-01, using the transit method. Its semi-major axis is 0.08 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of TOI-178 e is 3.861 times the mass of Earth. The radius of TOI-178 e is 2.207 that of Earth. With a mass below 5 Earth masses, a density of 0.36, and a semi-major axis of 0.0783 astronomical units, TOI-178 e could, potentially, be an ocean world - a planet with no dry land.
TOI-178 f was discovered by the Multiple Observatories observatory, in 2021-01, using the transit method. Its semi-major axis is 0.10 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of TOI-178 f is 7.724 times the mass of Earth. The radius of TOI-178 f is 2.287 that of Earth. At more than 10 Earth masses, TOI-178 f 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.
TOI-178 g was discovered by the Transiting Exoplanet Survey Satellite (TESS) observatory, in 2021-01, using the transit method. Its semi-major axis is 0.13 astronomical units, as compared to Earth's which is 1 astronomical unit. The mass of TOI-178 g is 3.943 times the mass of Earth. The radius of TOI-178 g is 2.870 that of Earth. With a mass below 5 Earth masses, a density of 0.166, and a semi-major axis of 0.1275 astronomical units, TOI-178 g could, potentially, be an ocean world - a planet with no dry land.