Nearest Earth-like Planet May be Right Next Door

Earth may be getting some company, according to researchers. Recently, astronomers used publicly available data from NASA's Kepler space telescope in order to determine that six percent of red dwarf stars have habitable, Earth-sized planets.

Red dwarf stars are both smaller and cooler than our own sun. In fact, an average red dwarf star is only about one-third as large and one-thousandth as bright as the sun. It's impossible to see any of these dim stars from Earth with the naked eye.

Yet astronomers weren't daunted. Red dwarf stars are excellent places to look for Earth-like planets since there are so many of them--three out of every four stars in our galaxy is a red dwarf. Led by Harvard astronomer Courtney Dressing, researchers culled the Kepler catalog of 158,000 target stars in order to identify all of the red dwarfs. Once these stars were picked out, Dressing then reanalyzed them in order to calculate more accurate sizes and temperatures. Surprisingly, she found that almost all of the stars were smaller and cooler than scientists once thought.

Dressing wasn't done, though. She then identified 95 candidates orbiting red dwarf stars that were approximately Earth-sized. Her findings implied that at least 60 percent of red dwarf stars have planets much smaller than Neptune. Yet size doesn't always matter. Dressing then narrowed down these candidates even further in order to find a total of three planetary candidates that were both warm and approximately Earth-sized. From this sample, she was able to conclude that about six percent of all red dwarf stars have an Earth-like planet.

These findings could have huge implications for the future of finding Earth-like planets. Instead of searching for them around stars like our own sun, it's possible to find them orbiting red dwarf stars, which are the most common type in our galaxy. Since about 75 percent of the closest stars to Earth are red dwarfs and about six percent of those should be habitable, the closest Earth-like planet could be just 13 light-years away.

Perhaps most interesting, though, is the idea that any life on these planets could be far older than what is found on Earth. Red dwarfs live much longer than sun-like stars, which means that life could potentially be more evolved on other planets.

Although the potential of Earth-like planets has risen, it remains to be seen whether life--highly evolved or otherwise--could exist on other planets.

The results will be published in The Astrophysical Journal.