Article of the Week - Kepler-22b

Kepler-22b
The closest planet to Earth that may be
habitable: it's about 600 light years away

Kepler-22b is the first confirmed extrasolar planet found by NASA's Kepler Space Telescope to orbit the habitable zone of a Sun-like star. Kepler-22b, a possible super-Earth, is roughly 600 light years away from Earth, in orbit around the G-type star Kepler-22.

The discovery was announced December 5, 2011. The planet was originally discovered on Kepler's third day of science operations in mid-2009. The third transit was detected in late 2010. Additional confirmation data was provided by the Spitzer Space Telescope and ground-based observations.

Kepler-22b's radius is roughly 2.4 times the radius of Earth, or about half that of Neptune. Its mass and surface composition remain unknown, with only some very rough estimates established.

The only parameters of the planet's orbit that are currently available are its period which is about two hundred and ninety days, and its inclination, which is such that it transits the disk of its star as seen from Earth.

No information is available about the shape of the planet's orbit. Many extrasolar planets are known to move in highly elliptical orbits. We only know that the semi-major axis of its orbit is within the habitable zone of an Earth mass planet. If Kepler-22b has a highly elongated orbit it may well only spend a small fraction of its time within this habitable zone.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Kepler-22b"