But the similarities end there. Both of the newfound planets reside in tight orbits around their parent star that ought to drive their surface temperatures to life-unfriendly extremes. Torres and his colleagues estimate that Kepler 20 f, the cooler of the two, has a temperature in the neighborhood of 430 degrees Celsius—hot enough to melt lead. "These are definitely too hot to be habitable, at least too hot to support life as we know it," he says.
In a separate study submitted to the Astrophysical Journal, the Kepler group reports finding three other small planets orbiting the same star, ranging from about two to three times the diameter of Earth. All five planets around Kepler 20 rank among the smallest-diameter planets discovered to date. (Astronomers have been able to measure the physical dimensions of only about 200 exoplanets to date; the diameters of another 500 or so planets are unknown.)
The Kepler 20 system has a very different architecture than does our solar system. For starters, all five worlds orbit closer to their host star than Mercury, the innermost planet in our solar system, orbits the sun. And unlike our solar system, where the inner planets are terrestrial worlds and the outer planets are gas giants, the Kepler 20 system is not neatly divided. "This system has gas worlds and rocky worlds," Torres says. "But they're all mixed up; they're not separated like in our own solar system. This is a very interesting thing that we have never seen before."
See what we're tweeting about
4 Comments
Add Comment2 thoughts:
Reply | Report Abuse | Link to this1. Is it possible to determine the orientation of a star's equatorial plane with current techniques? Does Kepler stare at all those stars and it just happens to get lucky when the planet's orbital plane intersects the Solar System? Or was the large sample size of stars analyzed beforehand to be made up of stellar systems whose orbital plane does intersect the Solar System?
2. Is anybody trying to model what some of these systems would look like and how many other planets are possible in these systems. The configuration around Kepler 20 might rule out any smaller planets further out that wouldn't cross in front of their parent star as often. Or it might not. The orbital dynamics of the planets we do know might preclude the existence of planets at different orbits or it might hint at their presence.
Given the fact that there are hundreds of billions of stars in the average galaxy, and hundreds of billions of galaxies in the known universe, and that our investigations so far indicate that a large percentage of stars have planets, I agree that it's only a matter of time before we discover planets almost exactly like Earth.
Reply | Report Abuse | Link to thisWe're now generating reasonably reliable estimates for the first two factors in the famous Drake equation, namely the average rate of star formation per year in our galaxy, and the fraction of those stars that have planets. The next factor, the average number of planets that can potentially support life per star that has planets, should be within our grasp after the next big space telescope is launched which can spectroscopically analyze the atmospheres of individual extrasolar planets. Then there will be only 4 factors left to pin down. Should only take a few million more years!
I would imagine that it should be possible to calculate an expected time when Kepler will produce an earth like planet in the Goldilocks zone. Obviously large and orbitally frequent planets should be first because large create greater light variation and frequent create more measurements to remove uncertainty. Surely we can extrapolate how long before Kepler will remove sufficient uncertainty on an Earthsize world in a Goldilocks zone. My prediction is the first will be closer to its star than ours and that that star will be smaller. Anyone have sufficient information to make the calc?
Reply | Report Abuse | Link to thisvery cool(ok hot)...and as the other posters noticed...this only works on systems that happen to have their plane in line with us....
Reply | Report Abuse | Link to this