October 31, 2011 - A NASA
spacecraft has identified an strange three-planet
system that is composed of one super-Earth
and two Neptune-size worlds orbiting a star similar to our sun, a new research reveals.
The planet-searching Kepler Space Telescope found the three planets around the star Kepler-18, which is only 10 p.c bigger than the sun and is made up of 97 percent of the sun's mass, scientists from the College of Texas at Austin stated. The alien system could also host far more planets than have been found so significantly, they added.
All three planets, which are designated Kepler-18b, c, and d, orbit considerably nearer to their guardian star than Mercury does to the sun. The world Kepler-18b orbits closest to the star, using 3.5 days to comprehensive its journey. The world is about 6.9 times the mass of Earth
and is twice the dimensions of our house world, making planet b a so-known as super-Earth, the scientists explained.
Kepler-18c, which requires 7.6 days to orbit the star, is about 5.5 times greater than our world, and has a mass equivalent to about 17 Earths. Kepler-18d has a 14.9-day orbit and is about 7 times the size of Earth, with a mass of about 16 Earths. In accordance to these figures, planets c and d qualify as reduced-density "Neptune-course" worlds, the scientists said. [The Strangest Alien
The findings have been offered Tuesday (Oct. 4) at a joint meeting of the European Planetary Science Congress and the American Astronomical Society's Division of Planetary Science in Nantes, France. The research will be published in a particular concern of The Astrophysical Journal
Supplement Series in November.
Scanning the cosmos
NASA's Kepler spacecraft hunts for exoplanets employing the transit method, which appears for periodic dips in a star's brightness over time that could show a world is passing in entrance of it from the telescope's viewpoint. The alien worlds close to Kepler-18 had been discovered making use of this method, but the orbits of the planets themselves were a point of interest to the researchers.
Kepler-18c orbits its mother or father star 2 times for each one orbit that Kepler-18d makes, defined examine leader Bill Cochran of The College of Texas at Austin. But the two planets do not cross the face of their mother or father star at these same orbital periods.
"One is somewhat early when the other one is slightly late, [then] the two are on time at the identical time, and then vice-versa," Cochran stated in a assertion.
This suggests that Kepler-18c and Kepler-18d are engaged in one thing of an orbital dance.