Half of Kepler's Exoplanets Aren't Really There: False Positives Discovered
It turns out that half of Kepler's exoplanet candidates may be false positives. New research reveals that 52.3 percent of the found exoplanets were actually eclipsing binaries, while 2.3 percent were brown dwarfs.
"It was thought that the reliability of the Kepler exoplanets detection was very good-between 10 and 20 percent of them were not planets," said Alexandre Santerne, one of the researchers, in a news release. "Our extensive spectroscopic survey, of the largest exoplanets discovered by Kepler, shows that this percentage is much higher, even above 50 percent. This has strong implications in our understanding of the exoplanet population in the Kepler field."
Giant transiting exoplanets are easily mimicked by false positives. In fact, spectroscopic follow-up observations are needed in order to establish the planetary nature of the transit detections, and easily reveal blended multiple stellar systems.
"Detecting and characterizing planets is usually a very subtle and difficult task," said Vardan Adibekyan, one of the researchers, in a news release. "In this work, we showed that even big, easy to detect planets are also difficult to deal with. In particular, it was shown that less than half of the detected big transiting planet candidates are actually there. The rest are false positives, due to different kind of astrophysical sources of light or noise."
The findings show that when it comes to discovering new planets, confirming them is important. This is particularly true as researchers continue their search for life outside of our solar system.
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