spacetoday.net: Astronomers find potential exoplanet smaller than Earth

Posted: Thu, Jul 19, 2012, 6:57 AM ET (1057 GMT)
UCF-1.01 exoplanet illustration (NASA/JPL-Caltech)

Astronomers examining data from NASA's Spitzer Space Telescope have found evidence for an extrasolar planet two-thirds the size of the Earth tightly orbiting its star. The University of Central Florida astronomers found the potential world in Spitzer observations of GJ 436, a star already known to have a Neptune-sized exoplanet, when they noted small, periodic dips in the star's infrared light that they believe are caused by another planet transiting the star's disk. If the object, designated UCF-1.01, is a planet, it would be two-thirds the diameter of the Earth, although its mass is unknown; it completes one orbit of GJ 436 in just 1.4 days, creating a surface temperature of about 600 degrees Celsius. Astronomers also detected evidence for a third planet, UCF-1.02, orbiting the star, but concluded there is not enough data to confirm the objects are planets, calling them planet candidates for now.