Hubblesite – Though astronomers have discovered thousands of planets orbiting other stars, very little is known about how they are born. The conventional wisdom is that planets coagulate inside a vast disk of gas and dust encircling newborn stars. But the details of the process are not well understood because it takes millions of years to happen as the disk undergoes numerous changes until it finally dissipates.
The young, nearby star AU Microscopii (AU Mic) is an ideal candidate to get a snapshot of planet birthing because the disk is tilted nearly edge on to our view from Earth. This very oblique perspective offers an opportunity to see structure in the disk that otherwise might go unnoticed. Astronomers are surprised to uncover fast-moving, wave-like features embedded in the disk that are unlike anything ever observed, or even predicted. Whatever they are, these ripples are moving at 22,000 miles per hour — fast enough to escape the star’s gravitational pull. This parade of blob-like features stretches farther from the star than Pluto is from our sun. They are so mysterious it’s not known if they are somehow associated with planet formation, or some unimagined, bizarre activity inside the disk.
Learn even more about AU Mic by joining the live Hubble Hangout discussion at 3:00 pm EDT on Thurs., Oct. 8 at http://hbbl.us/y6M.
Here is a great video about the newly announced Kepler 452b with SETI scientists: Douglas Caldwell, Jeffrey Coughlin, Joseph Twicken. and hosted by Seth Shostak.
The Hangout fills in a lot of the blanks from the news reports. As I expected we don’t yet have a mass or density on this planet. Once we get at least a good estimate on these numbers for 452b then we will be able to make better guesses on its composition.
We have an estimate of the diameter so that’s a start, but it’s only one bit of the equation that defines the balance the must exist. If for example, 452b has the density of Earth, we might expect an atmosphere to be much different than we have, ranging up to perhaps even Neptune-like. On the other hand the mass could be much less and the weaker gravity could allow more of the lighter gasses to be lost to space.
I am bound to guess we are very close to finding a real Earth analog. It is astounding how quickly the search is progressing.
Not so long ago there were no other planets around other stars known. Now we have over 1,500 and thoussands more candidates. The Kepler now has over 1000 confirmed planets to its credit.
So far out of all those Kepler planets, eight are less than Earth sized and are inside of the habitable zones of their parent stars. So not only are they warm enough for life like we know it, the size of the planet means the atmosphere could have similar charateristics to our own thanks to gravity. That isn’t to say they actually do, just that the potential is there. I would like to think eventually those atmospheres will be charachterized. In the mean time the search continues.
How many stars like our sun host planets like our Earth? NASA’s Kepler Space Telescope continuously monitored more than 150,000 stars beyond our solar system, and to date has offered scientists an assortment of more than 4,000 candidate planets for further study — the 1,000th of which was recently verified.
Using Kepler data, scientists reached this millenary milestone after validating that eight more candidates spotted by the planet-hunting telescope are, in fact, planets. The Kepler team also has added another 554 candidates to the roll of potential planets, six of which are near-Earth-size and orbit in the habitable zone of stars similar to our sun.
Three of the newly-validated planets are located in their distant suns’ habitable zone, the range of distances from the host star where liquid water might exist on the surface of an orbiting planet. Of the three, two are likely made of rock, like Earth.
A few fun facts:
Kepler-10c is 2.227 Earth radii with a similar density so it’s HUGE for a rocky planet, 17 times larger than Earth. A fact that has scientists scratching their heads on how this could be, it was thought not possible.
The parent star Kepler 10 is similar to our own Sun. Kepler-10c orbits much closer to its sun than we do ours, only 25 percent as far, this means of course the planet is hot somewhere near 212 oC / 413oF. It’s also orbits very quickly, a Kepler-10 c year is only 45.29 days.
Visit the Kepler page for all the details including how the planet was discovered.
Here is the Kepler press release:
Astronomers have discovered a rocky planet that weighs 17 times as much as Earth and is more than twice as large in size. This discovery has planet formation theorists challenged to explain how such a world could have formed.
“We were very surprised when we realized what we had found,” says astronomer Xavier Dumusque of the Harvard-Smithsonian Center for Astrophysics (CfA), who led the analysis using data originally collected by NASA’s Kepler space telescope.
Big news! Kepler-186f is the FIRST rocky Earth-sized exo-planet found! I am hoping this is just the first of a new series of discovery.
Being in the habitable zone means there is a possibility first of an atmosphere. If there is an atmosphere the similar Earth size then it could be possible to have an atmosphere more like our own. At the very least Hydrogen and Helium should be lacking as it is here, because as you know both of those gases are made of small and light atoms; those atoms move fast and at Earth temperatures, that velocity exceeds Earth’s escape velocity. Planets like Jupiter and the other gas giants have more gravity and are colder so Hydrogen and Helium are retained.
Then of course that only after an atmosphere you have to have the rest of the pieces. Or Kepler-186f could be just a big rock.
We are a long way from knowing the details on Kepler-186f, but just finding a planet of Earth size and in the habitable zone is an excellent start!
Here’s the press release from NASA (great wallpaper too!):
The artist’s concept depicts Kepler-186f , the first validated Earth-size planet to orbit a distant star in the habitable zone—a range of distance from a star where liquid water might pool on the planet’s surface. The discovery of Kepler-186f confirms that Earth-size planets exist in the habitable zones of other stars and signals a significant step closer to finding a world similar to Earth.