Red dwarf stars give out "false positives" on life on planets around them, making the hunt for habitable planets trickier than previously thought.
The search for habitable exoplanets has been the number one mission for many space agencies. Scientists have not restricted themselves to search for life around planets surrounding sun-like stars but they also search planets that orbit red dwarfs. These are stars smaller than the sun but make up more than 75 percent of the stars in the sun's vicinity.
The ultra violet environment of these stars is very different from the sun and in a new study; researchers found that this could further complicate the hunt for habitable planets.
"Before we can claim the discovery of life on exoplanets, we have to examine the stars harboring these planets more carefully," study leader Feng Tian, a professor at the Center for Earth System Science at Tsinghua University in Beijing, China, said in a statement. He presented the research Monday in Denver at the 45th annual meeting of the American Astronomical Society's Division for Planetary Sciences.
Red dwarfs were found to give off "false positive" signals of life on planets. For the study, researchers looked at Earth-mass planets in the neighborhood of four stars, such as GJ 667. This star is known to have three planets in its orbit that could be habitable.
High levels of oxygen detected on an exoplanet are one of the indications scientists use to determine whether the planet is habitable. However, in the new study researchers found that some red dwarfs indicate high oxygen levels on some planets even if they are lifeless. Researchers of an earlier study used the idea of a hypothetical habitable planet orbiting GJ 876 to test this theory.
"Professor Feng Tian's research addresses one of the most important questions of contemporary astrophysics and indeed of great interest to the general public: Are there other habitable planets near Earth, and is there any evidence that they are indeed inhabited?" Jeffrey Linsky of the University of Colorado at Boulder, said in a statement, according to NBC News.
