Amateur Technology Finds Super-Earth
Astronomers announced today that they 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.
The discovery is being published in the December 17 issue of the journal Nature.
A super-Earth is defined as a planet between one and ten times the mass of the Earth. The newfound world, GJ1214b, is about 6.5 times as massive as the Earth. Its host star, GJ1214, is a small, red type M star about one-fifth the size of the Sun. It has a surface temperature of only about 4,900 degrees F and a luminosity only three-thousandths as bright as the Sun.
GJ1214b orbits its star once every 38 hours at a distance of only 1.3 million miles. Astronomers estimate the planet’s temperature to be about 400 degrees Fahrenheit. Although warm as an oven, it is still cooler than any other known transiting planet because it orbits a very dim star.
Since GJ1214b crosses in front of its star, astronomers were able to measure its radius, which is about 2.7 times that of Earth. This makes GJ1214b one of the two smallest transiting worlds astronomers have discovered (the other being CoRoT-7-b). The resulting density suggests that GJ1214b is composed of about three-fourths water and other ices, and one-fourth rock. There are also tantalizing hints that the planet has a gaseous atmosphere.
“Despite its hot temperature, this appears to be a waterworld,” said Zachory Berta, a graduate student at the Harvard-Smithsonian Center for Astrophysics (CfA) who first spotted the hint of the planet among the data. “It is much smaller, cooler, and more Earthlike than any other known exoplanet.”
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