Earthlike planets could be close at hand

Posted by Kate Taylor

There's probably an Earth-sized planet with a comfortable temperature as little as 13 light years away, data from NASA’s Kepler space telescope implies.

An analysis from the Harvard-Smithsonian Center for Astrophysics (CfA) indicates that six percent of red dwarf stars in the galaxy have Earth-size planets in the habitable zone. And, given that most of our neighbouring stars are red dwarfs, the oddsd are there's one nearby.

"We don't know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined," says Natalie Batalha of NASA's Ames Research Center.

The research team analyzed 95 planet candidates in the Kepler catalog orbiting 64 red dwarf stars. While most aren't the right size or temperature to be considered Earth-like, three are both temperate and smaller than twice the size of Earth.

Because red dwarf stars are smaller, cooler, and fainter than the sun, the habitable zone would be much closer to a cooler star than it is to the sun.

"This close-in habitable zone around cooler stars makes planets more vulnerable to the effects of stellar flares and gravitational interactions, complicating our understanding of their likely habitability,” says Victoria Meadows, professor at the University of Washington and principal investigator with the NASA Astrobiology Institute.

"But if the planets predicted by this study are indeed found very nearby, then it will make it easier for us to make the challenging observations needed to learn more about them, including whether or not they can or do support life."

The three planetary candidates highlighted in this study are Kepler Object of Interest (KOI) 1422.02, which is 90 percent the size of Earth in a 20-day orbit; KOI-2626.01, 1.4 times the size of Earth in a 38-day orbit; and KOI-854.01, 1.7 times the size of Earth in a 56-day orbit.

Located between 300 to 600 light-years away, all three orbit stars with temperatures ranging from 3,400 to 3,500 degrees Kelvin. By comparison, the temperature of the sun is nearly 5,800 degrees Kelvin.