Two months after the first discovery of an exoplanet orbiting in the habitable zone of a sun-like star and one month after the first discovery of the two exoplanets similar in size to Earth (Kepler-20e and Kepler-20f, pictured above), researchers using the Keck Observatory in Hawaii and public data from NASA’s Kepler mission have discovered the smallest exoplanets yet. Working from a tip from amateur astronomer Kevin Apps, they found three tiny exoplanets closely orbiting red dwarf star KOI-961, which is 120 light years away in the Constellation Cygnus (The Swan) and is about one-sixth the size of the sun. All three exoplanets are smaller than our planet at 0.57, 0.73, and 0.78 the diameter of Earth. The smallest is called KOI-961.03 and is only 8% larger than Mars.
Unfortunately, all three rocky exoplanets are too hot to support life, making a full orbit around their star in fewer than 48 hours. Their surface temperatures are an estimated 350°F to 836°F (177°C to 447°C). This brings the total number of confirmed exoplanets to about 35, while Kepler has over 2,300 possible exoplanets flagged for further observation, and SPACE reports that Kepler scientists expect about 80% of these 2,300 possibilities to be confirmed as exoplanets.
In addition to the estimate from Keplar scientists, researchers at the University of Copenhagen recently released the results of six years of study:
“Our results show that planets orbiting around stars are more the rule than the exception. In a typical solar system approximately four planets have their orbits in the terrestrial zone, which is the distance from the star where you can find solid planets. On average, there are 1.6 planets in the area around the stars that corresponds to the area between Venus and Saturn” explains astronomer Uffe Gråe Jørgensen
They estimate that one out of every ten stars in our galaxy are likely to have a planet roughly the size of the Earth orbiting in the habitable zone. If those planets also have water and an atmosphere similar to ours, we could live there. Dibs. I just called dibs.