The new year has gotten off to a pretty hot start. So far, scientists have discovered 10 new exoplanets – or planets outside of our solar system. That brings the total number of confirmed exoplanets to 726. Do you feel a little bit smaller? I sure do.
Most recently, three rocky, smaller than Earth-sized planets were found orbiting a red dwarf.
Artist's concept of the KOI-961, with three planets all smaller than Earth: The smallest of the three planets, called KOI-961.03, is about the size of Mars and actually located the farthest from the star, but is pictured in the foreground. The planet in the upper right is KOI-961.01, 0.78 times the radius of Earth. The planet closest to the star is KOI-961.02, with a radius 0.73 times the Earth's. Caption and image courtesy of NASA/JPL-Caltech
Since the planets orbit relatively close to their sun – KOI-961 – it would seem that the bodies wouldn’t be able to sustain life. However, a red dwarf is a relatively cool star and … well, you never really know. Life doesn’t have to be intelligent to count as life, right?
While the planet is not in the “habitable zone” – a region where liquid water could exist – this is still a very important discovery. Why? Well, most of the planets discovered outside of our solar system have been massive gas giants. There’s only been a handful of smaller, rocky planets that have been discovered.
According to John Johnson, the principal investigator of the research from NASA’s Exoplanet Science Institute at the California Institute of Technology in Pasadena:
This is the tiniest solar system found so far … It’s actually more similar to Jupiter and its moons in scale than any other planetary system. The discovery is further proof of the diversity of planetary systems in our galaxy
This chart compares the smallest known exoplanets, or planets orbiting outside the solar system, to our own planets Mars and Earth. The smallest, KOI-961.03, is about the size of Mars with a radius of only 0.57 times that of Earth. Caption and image courtesy of NASA/JPL-Caltech
Another “Star Wars-like” planetary system
An artist's rendition of the Kepler-35 planetary system. Kepler-35b orbits its smaller and cooler host stars than our sun every 131 days, and the stellar pair orbits each other every 21 days. Caption courtesy of NASA. Image courtesy of Lynette Cook / extrasolar.spaceart.org
Last September, we found a planet called Kepler-16b that was just like Star Wars’ Tatooine – a planet with two stars. And now, only four months later, scientists have discovered another system just like that.
Saturn-sized Kepler-34b and Kepler-35b were recently discovered to orbit a pair of stars. The system is called a circumbinary planetary system.
“This work establishes that such ‘two sun’ planets are not rare exceptions, but are in fact common with many millions existing in our Galaxy,” a NASA release stated.
Each of these discoveries was due to data provided by NASA’s Kepler mission, which has already helped confirm 35 exoplanets and identify over 2,000 planetary candidates.
Want to read more about the other eight planets found this year? Check out the Extrasolar Planets Encyclopedia.
Curious to see some of the strangest alien planets discovered so far? Space.com has a fabulous gallery you’ve got to see.