Illustration depicts the relative size and temperature of the new planets.
Credit: William Borucki/NASA
WASHINGTON DC: NASA's Kepler space telescope has discovered five new planets beyond the Solar System, just 10 months after it launched into space to find Earth-like planets.
The discovery of the five exoplanets "contributes to our understanding of how planetary systems form and evolve from the gas and dust disks that give rise to both the stars and their planets," said NASA's William Borucki, principal science investigator for the Kepler mission.
But all five exoplanets are too hot for life as we know it, the U.S. space agency said.
Lowest density
The newly discovered planets are known as "hot Jupiters" because of their large masses and extreme temperatures, which range from 1,200 to 1650 ºC – hotter than molten lava. Their orbits last between three and five days, meaning they follow paths close to their stars, which are all hotter and larger than the Earth's Sun.
The smallest of the newly discovered planets is roughly the size of Neptune, the fourth largest planet in our Solar System, and the biggest is around the size of Jupiter, the largest planet in our Solar System.
One of the planets – which have been given the names Kepler-4b, -5b, -6b, -7b and -8b – is similar in many ways to Neptune, although its irradiation level is much higher.
Dips in brightness
Another planet is one of the least dense ever discovered, and along with the other three, confirms the existence of planets with densities substantially lower than those predicted for gas giant planets.
The five exoplanets were among discoveries made by the Kepler space telescope in the first six weeks after it became operational in May 2009. Borucki presented the early discoveries and other findings at a meeting of the American Astronomical Society in Washington DC on Monday.
Kepler looks for the signatures of planets by measuring dips in a star's brightness which are caused by planets crossing in front of them and periodically blocking out part of the starlight. The size of the planet can be derived from the size of the dip in brightness while the temperature can be estimated from the characteristics of the star it orbits and the planet's orbital period.
