Q47268

Kepler-10b is the first confirmed terrestrial planet to have been discovered outside the Solar System by the Kepler Space Telescope. Discovered after several months of data collection during the course of the NASA-directed Kepler Mission, which aims to discover Earth-like planets crossing in front of their host stars, the planet's discovery was announced on January 10, 2011. Kepler-10b has a mass of 3.72±0.42 Earth masses and a radius of 1.47 Earth radii. However, it lies extremely close to its star, Kepler-10, and as a result is too hot to support life as we know it. Its existence was confirmed using measurements from the W.M. Keck Observatory in Hawaii.

==Nomenclature and history== Kepler-10, the star that hosts Kepler-10b, is located 560 light-years from the Solar System in the Draco constellation. It is approximately the same size as the Sun, with an estimated age of 12 billion years. Planet Kepler-10b was the first planet to be discovered in the orbit of its star. For this, it was designated the star's b planet. The star, in turn, was named for the Kepler Mission, a NASA-led operation aimed at discovering terrestrial planets that transit, or cross in front of, their host stars with respect to Earth. The planet's discovery was announced to the public on January 10, 2011. thumb|left|170px|The light curve for Kepler-10b, demonstrating the dimming effect as it transits its star The transit method of discovering exoplanets relies upon carefully monitoring the brightness of a star. If a planet is present and crosses the line of sight between Earth and the star, the star will dim at a regular interval by an amount that depends upon the radius of the transiting planet. In order to measure the mass of a planet, and rule out other phenomena that can mimic the presence of a planet transiting a star, candidate transiting planets are followed up with the radial velocity method of detecting extrasolar planets.