The first planet in the habitable zone around a Sun-like star was discovered by the Kepler telescope. The new object was named Kepler 22-b. It revolves around a star, which is located at a distance of 600 light years away from Earth. The star belongs to the G spectral class (which is the same spectral class as our Sun), but it is slightly smaller and cooler than the Sun – the brightness of the star is about ¾ of our Sun’s.
Kepler 22-b revolves around its star in 290 days. The radius of the planet is about 2.4 times larger than the Earth. Scientists do not know the mass of the planet, so it is not possible to estimate its density and hence the approximate composition. It is quite possible that the planet may consist almost entirely of gas.
The planet is also known as Christmas Planet. It got it’s nickname because it took three snapshots for the Kepler telescope to determine the planet was really there, and the snapshots had to be taken 290 days apart (the length of planet’s year). The last of those three encounters happened during the 2010 holiday season.
According to the scientists, to date, Kepler telescope has found 54 candidates for a potentially habitable planet. Habitable zone around a star is a region where the planet’s surface (if it exists) can potentially have liquid water.
Space telescope Kepler was launched into space in March 2009. It continuously scans the area in the sky, containing about 4.5 million stars, which is located between Cygnus and Lyra constellations. Scientists find extrasolar planets by monitoring changes in star brightness caused by the passage of a body across the disk of a star (so-called transit method).
[images - nasa.gov]
