A plethora of planets

As expected, the next major update from the Kepler mission came today and did not disappoint. The number of known extrasolar planets continues to grow exponentially. As of today, the number of confirmed planets is 525, including six new confirmations from Kepler (all in one solar system) as well as other telescopic surveys. The number of Kepler candidates, awaiting final confirmation, is now 1,235! Of those, 68 are Earth-size or smaller, 288 are super-Earth size, 662 are about Neptune-size and 165 are Jupiter-size or larger. More significantly, 54 are in the “habitable zone” of their stars, orbiting at a distance where liquid water could exist on the surface of rocky planets. Five of those are near Earth-size. 170 of the stars appear to have multi-planet systems.

Credit: NASA/Wendy Stenzel
Credit: NASA/Wendy Stenzel

The star with the six newly confirmed planets, named Kepler-11, is about 2,000 light-years from Earth. The orbits of all six planets would fit within the orbit of Venus in our solar system:

Credit: NASA/Tim Pyle

For those who missed the press conference, it can be viewed here.

And remember, by design, Kepler is only able to view a tiny fraction of the stars in our galaxy (about 156,000 stars in 1/400th of the sky), and detect planets whose orbits are edge-on as seen from Earth, so they transit the stars being studied, as viewed from Earth. So all of these findings so far still only represent a very small percentage of all of the stars in our galaxy alone…

I’ve also updated the exoplanetary count in the right-hand column of the blog to show both confirmed planets (from Kepler and other telescopic surveys) and other candidate planets (from Kepler). Again by design, planets detected by Kepler take longer to confirm, especially smaller ones in the habitable zones of stars, with periodic announcements of candidates to-date.