Study disproves signal clues from two potentially habitable planets

Washington: Scientists have revealed that the controversial signals were not coming from the two planets, which might support life, orbiting the dwarf star Gliese 581.

Suvrath Mahadevan, an assistant professor of astronomy and astrophysics at Penn State, said they have proven that some of the other controversial signals were not coming from two additional proposed Goldilocks planets in the star`s habitable zone, but instead were coming from activity within the star itself. Paul Robertson, a postdoctoral fellow at Penn State, said that it had explained, for the first time, all the previous and somewhat conflicting observations of the intriguing dwarf star Gliese 581, a faint star with less mass than our Sun that is just 20 light years from Earth. He further explained that their improved detection of the real planets in this system gave them confidence that they are now beginning to sufficiently eliminate Doppler signals from stellar activity to discover new, habitable exoplanets, even when they are hidden beneath stellar noise. The research team made its discovery by analyzing Doppler shifts in existing spectroscopic observations of the star Gliese 581 obtained with the ESO HARPS and Keck HIRES spectrographs and the Doppler shifts that the scientists focused on were the ones most sensitive to magnetic activity. The study is published by the journal Science in its online Science Express issue.