More than 100 new exoplanets discovered
Many Earth-like planets and multi planetary systems around red dwarfsRead out
100 in one go: Astronomers have tracked down a whole sweep of new exoplanets with the help of the Kepler Space Telescope. Among these are especially many earth-like rock planets orbiting small, faint stars - and several potential Earth twins. Particularly exciting is a planetary system with four possible super-earths, two of which circle in the habitable zone of their star, as the researchers report.
Much of the nearly 3, 500 known exoplanets have been detected by astronomers using NASA's Kepler Space Telescope. This is specifically designed to spot the signal of smaller, Earth-like planets as they transit through their star. Among his finds are among other things first earth twins in the habitable zone around their stars and also the largest exoplanet with two suns.
Many earth-like planets
Now astronomers around Ian Crossfield from the University of Arizona have identified 104 new exoplanets at once. For their study, they evaluated the Kepler data from 194 planetary candidates and performed follow-up observations with the help of Earth-based telescopes. "104 of these candidates proved to be true, bona fide planets, " the researchers report.
Most of these extrasolar planets revolve around red dwarfs and other small, moderately bright stars. Their diameter ranges from less than Earth size to enormous gas giants, as the astronomers report. "Among the new discoveries are some multi-planetary systems and several small, roughly earth-sized planets that receive about as much radiation from their star as the Earth, " said Crossfield and his colleagues.
A system with four super-earths
One of the most exciting discoveries is the K2-72 system (EPIC 206209135). It is a dwarf star of about 49 percent of the sun's mass, which is orbited by four super-earths. These are between 20 and 50 percent larger than the earth and thus most likely belong to the rock planets. displayThe Kepler telescope searches five sky fields along the ecliptic in its K2 mission. NASA
All four exoplanets circle their star relatively closely: their laps last between 5.5 and 24 days. However, because the star is relatively faint, at least two of the planets could be in the habitable zone, as the astronomers report. Earlier studies had suggested that there could be many smaller, earth-like planets around the Milky Way red dwarfs.
Red Dwarfs as a hoard of life?
"Because these little stars occur so often in the Milky Way, life in space could have been much more common on planets around such cool red stars than on planets around sunlike ones Stars, "says Crossfield. Therefore, he and his colleagues have targeted the Kepler telescope to more near, faint dwarf stars.
Ironically, these discoveries were only made possible by the failure of two reaction wheels of the Kepler telescope in 2013. As a result, the telescope could no longer be focused accurately enough on its actual target, a sky detail in the constellation of swan. Since then, the so-called K2 mission allows only observations along the ecliptic and that's where the explorers spotted the new planets.
"The K2 mission has already increased the number of known small exoplanets in orbit by moderately bright stars by 30 percent, " the researchers note. (Astrophysical Journal Supplement Series, in press)
(WM Keck Observatory, 19.07.2016 - NPO)