Watching the Skies

A new facility designed to scan space for exoplanets has just successfully completed its first observation run. The French-led Exoplanets in Transits and their Atmospheres (ExTrA) project is housed at the European Southern Observatory’s (ESO) La Silla Observatory in Chile, and it is funded by the European Research Council and the Agence National de la Recherche in France.

ExTrA is no ordinary planet hunter. Its three 0.6 meter (1.98 feet) telescopes continually scan nearby red dwarf stars for signs of exoplanets by monitoring the amount of light they project. A dip in brightness could signal the passing of an orbiting exoplanet across the side of a red dwarf star that’s facing the Earth. The ExTrA telescopes compare the brightness of each observed star with that of four other reference stars to help spot changes.