Kepler-47

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Template: Infobox double star / Maintenance / RekDekSizeLeer

Kepler -47 is a double star system, which is surrounded by two exoplanets. It was after Kepler -16, the second discovered system in which a double star is orbited by planets and the first known such system with more than one planet. Such systems are usually due to the complex path dynamics to be very unstable. Noteworthy is the joint plane of the path of the planet. The planets were discovered in 2012 using the transit method from the space telescope Kepler. Kepler -47 is about 4900 light years away and is located in the constellation Cygnus.

The stars orbit each other in 7.45 days. The larger of the two stars has a size similar to the sun, but only 84 % of its luminosity, while the smaller one has only a third of the sun size.

The inner planet, Kepler -47 b, orbits two stars in 49.5 days and has a radius of about three Earth radii. Its mass is unknown and it can therefore no conclusions on its possible composition are drawn.

The outer planet, Kepler -47 c, is located in the habitable zone. Its orbital period is 303.2 days. He is with a radius of less than 5 Earth radii slightly larger than Uranus. Its mass is not known; probably it is approximately in the range of a Neptune mass.