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Kepler: Many Red Dwarfs Have Earth-SIzed Planets Too

Posted by Unknown on from the prepare-for-invasion dept.

astroengine writes "Extrapolating from findings by NASA's planet-hunting Kepler Space Telescope, scientists on Wednesday said roughly six percent of so-called red dwarf stars have Earth-sized planets properly positioned around their parent stars so that liquid water could exist on their surfaces. The team looked at 95 candidate planets circling red dwarf stars observed by Kepler and found that at least 60 percent have planets smaller than Neptune. Most were not the right size or temperature to be Earth-like, but three were found to be both warm and approximately Earth-sized. Statistically that would mean six percent of all red dwarf stars should have a Earth-sized planet. Since 75 percent of the closest stars are red dwarfs, the nearest Earth-like world may be just 13 light-years away."

7 of 132 comments (clear)

  1. 14 LY from earth? by Anonymous Coward · · Score: 4, Interesting

    Not to nerd out but wouldn't that make it Vulcan?

    1. Re:14 LY from earth? by mcgrew · · Score: 3, Interesting

      Vulcan circles a red dwarf? Wikipedia says nothing about the planet or its star, just about the Vulcans themselves. I was thinking Krypton, even though I haven't read a Superman comic since I was 7 or 8; it orbits a red star.

      I'm always amused by "only n light years away" in every story about a newly-found planet. Adams was right. "Space is big. I mean really big. You think it's a long way to the chemist..." the Voyagers have been traveling for 40 years and still haven't gotten past the heliopause. Even Adams was understating the vast distances between stars, try as he might to impress how big space is. Getting to Vulcan/Krypton is indeed infinitely improbable, at least for the next few hundred years and maybe never.

      Depressing, isn't it?

      --
      Free Martian Whores!
  2. Nice thing about red dwarf stars by PvtVoid · · Score: 4, Interesting

    One attractive feature of red dwarf stars, it would seem to me, is that they have much longer lifetimes than sun-like stars. More time for complex life to evolve!

    1. Re:Nice thing about red dwarf stars by K.+S.+Kyosuke · · Score: 5, Interesting

      One attractive feature of red dwarf stars, it would seem to me, is that they have much longer lifetimes than sun-like stars. More time for complex life to evolve!

      On the other hand, being (necessarily, due to temperature issues) much closer to their star, these planets are likely to be tidally locked, which is *not* a good thing for complex life trying to evolve.

      --
      Ezekiel 23:20
    2. Re:Nice thing about red dwarf stars by Anonymous Coward · · Score: 2, Interesting

      Tidal locking by itself is not a fatal problem. For example, it has been estimated that if Earth were tidally locked, the night side temperature would be fairly frosty bottoming out at -33 C but that's nowhere near cold enough to cause the atmosphere to freeze out. An atmosphere anywhere above 10% of Earth's is sufficient to transfer heat to the night side. Water ice accumulation would not be a problem either, since the oceans would be free to flow underneath an ice sheet.

      However, tidal heating could be a problem for such a close orbit. Planetary orbits don't start out near-perfectly circular, there's a period of time during which the orbit of a planet is eccentric. This induces a strongly variable tidal force that will heat up the planet and burn off any volatiles like water. You would have to introduce water (e.g. by comet impacts) after the orbit has settled at low eccentricity.

    3. Re:Nice thing about red dwarf stars by HiThere · · Score: 3, Interesting

      That was the old theory. Currently, IIUC, it is only believed to apply if there is no atmosphere. If there is an atmosphere, its circulation redistributes the heat...though slowly enough that there is, indeed, a huge difference in temperatures between the day side and the night side. Naturally, exact details depend on the composition of the atmosphere. (If Venus were tidally locked, it wouldn't change much of anything.)

      --

      I think we've pushed this "anyone can grow up to be president" thing too far.
  3. Re:Um... by Anonymous Coward · · Score: 2, Interesting

    The summary is a bit difficult to interpret. For example, it seems like they're reporting percentages only considering red dwarf stars with planets, and then extrapolating to red dwarf stars (undetermined with/without planets). Perhaps this explains how they got a 6% estimate when 3/95 is much closer to 3%. With a 3/95 proportion of "earth-like planets" to "no earth-like planets" the 95% confidence interval for the probability of having an "earth-like" planet around a red dwarf (with planets?) is 0.66% to 8.95%. The only way to actually determine the closest "earth-like" planet orbiting a red dwarf would be to actually examine each red dwarf in order of nearness. Statistics always have uncertainties, and it would be awesome if those uncertainties were reported along with the "most likely" or "best guess" at the true value. I suppose it's too confusing for most.

    In case you want to play with the confidence intervals:
    http://statpages.org/confint.html