An Earth-like exoplanet in mass and size discovered
MIT researchers have found that Kepler 78b, a small, intensely hot planet 400 light-years from Earth discovered by the researchers in August, shares Earth’s mass.
By analyzing the movement of its host star, Kepler 78, the scientists determined that the exoplanet is about 1.7 times as massive as the Earth.
From the same measurements, they calculated that the planet’s density is 5.3 grams per cubic centimeter, closely resembling Earth’s density (5.5 grams per cubic centimeter). The findings make Kepler 78b the smallest exoplanet for which the mass and size are known. These new measurements provide strong evidence that Kepler 78b is composed mostly of rock and iron, similar to Earth.
