NEW PLANETS DISCOVERED IN NEW YEAR OF 2012

 NEW PLANETS DISCOVERED IN NEW YEAR OF 2012

NASA's Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. Such systems will help astronomers better understand how planets form.

The planets orbit close to their host stars and vary in size from 1.5 times the radius of Earth to larger than Jupiter. Fifteen are between Earth and Neptune in size. Further observations will be necessary to find out which are rocky like Earth and which have thick gaseous atmospheres like Neptune. The planets orbit their host star once every six to 143 days. All are closer to their host star than Venus is to our sun.
Prior to the Kepler mission, we knew of perhaps 500 planets outside of the Solar System across the whole sky. Now, in just two years staring at a piece of sky not much bigger than your fist, Kepler has discovered more than 60 planets and more than 2,300 planet candidates. This tells us that our galaxy is absolutely loaded with planets of all sizes and orbits.
Kepler identifies planet candidates by repeatedly measuring the change in brightness of more than 150,000 stars to discover when a planet passes in front of the star. That passage casts a small shadow toward Earth and the Kepler spacecraft.
By exactly timing when each planet passes its star, Kepler discovered the gravitational pull of the planets on each other, confirming the case for 10 of the newly announced planetary systems. Five of the systems (Kepler-25, Kepler-27, Kepler-30, Kepler-31 and Kepler-33) contain a pair of planets where the inner planet orbits the star twice during each orbit of the outer planet. Four of the systems (Kepler-23, Kepler-24, Kepler-28 and Kepler-32) contain a combination where the outer planet circles the star twice for every three times the inner planet orbits its star.
Kepler-33, a star that is older and more massive than our sun, had the most planets. The system hosts five planets, varying in size from 1.5 to 5 times that of Earth. All of the planets are placed closer to their star than any planet is to our sun.
The features of a star provide clues for planet detection. The decrease in the star's brightness and length of a planet’s journey combined with the features of its host star present a recognizable mark. When astronomers detect planet candidates that exhibit similar signatures around the same star, the possibility of any of these planet candidates being a false positive is very low.