Newly discovered super-Earth GJ 1214b, which orbits a red dwarf star 40 light-years from Earth. It was discovered by the MEarth project - a small fleet of ground-based telescopes no larger than those many amateur astronomers have in their backyards. David A. Aguilar, CfA [View Larger Image]December 16, 2009
Astronomers have discovered a "super-Earth" orbiting a red dwarf star 40 light-years from Earth. They found the distant planet with a small fleet of ground-based telescopes no larger than those many amateur astronomers have in their backyards. Although the super-Earth is too hot to sustain life, the discovery shows that current, ground-based technologies are capable of finding almost-Earth-sized planets in warm, life-friendly orbits.
A super-Earth is defined as a planet between one and ten times the mass of the Earth. The newfound world, GJ 1214b, is about 6.5 times as massive as Earth. Its host star, GJ 1214, is a small, red type M star about one-fifth the size of the Sun. It has a surface temperature of only about 4900° Fahrenheit (2900° Celsius) and a luminosity only three-thousandths as bright as the Sun.
GJ 1214b orbits its star once every 38 hours at a distance of only 1.3 million miles (2.1 million kilometers). Astronomers estimate the planet's temperature to be about 400° Fahrenheit (200° Celsius). Although warm as an oven, it is still cooler than any other known transiting planet because it orbits a very dim star.
Since GJ 1214b crosses in front of its star, astronomers were able to measure its radius, which is about 2.7 times that of Earth. This makes GJ 1214b one of the two smallest transiting worlds astronomers have discovered.
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