Exoplanet search turns to dwarf star systems

Nature : The search for extraterrestrial life is leading some scientists to scan the skies for M-dwarf stars. Because those stars are smaller and cooler than our Sun, any transiting planets would block more of their starlight, making them easier to detect. Also, the cooler the star, the closer its habitable zone, where Earth-like planets could exist; such planets would orbit more closely and transit more often, thus providing more opportunity for being detected. However, an initial search by the MEarth Project , which was launched in 2009 by David Charbonneau at the Harvard–Smithsonian Center for Astrophysics in Massachusetts, has turned up only one such exoplanet in the past four years. The reason could be size—MEarth can only detect planets twice the size of Earth. As more such M-dwarf-seeking projects go online, Charbonneau plans to focus more telescopes on fewer stars for longer periods of time in the hope of detecting smaller candidate planets, which are potentially much more numerous.