Kepler Telescope Discovers 715 New Planets

By Carl Engelking | February 26, 2014 3:13 pm

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NASA’s Kepler Space Telescope may be down, but it’s not out, and its data collection is the gift that keeps giving.

Scientists on Wednesday announced the discovery of 715 new exoplanets. As the largest windfall of validated planets the space agency has ever revealed at one time, it doubles the number of planets known to humanity outside our solar system.

All of these planets exist within multi-planet systems similar to our own, and 95 percent are smaller than Neptune. Four are even within the habitable zone, which means they could theoretically support life-giving liquid water on their surfaces.

“We’ve been able to open the bottleneck to access the mother lode and deliver to you more than 20 times the planets than had ever been announced previously,” said Jack Lissauer, planetary scientist at NASA Ames Research Center.

Finding the Mother Lode

Kepler’s latest delivery opens up fresh territory, allowing astronomers to study both individual planets and their configurations within planetary systems.

Since Kepler launched in March 2009, it has identified more than 3,600 possible exoplanets, but most have yet to be confirmed — a process that requires further observation of each candidate world. To this point, confirming planets has been a laborious, slow process. However, scientists used a new statistical technique to open the bottleneck and find hundreds of new planets with relative ease.

Kepler detects planetary candidates by measuring the brief dimming of a star’s brightness as an object passes in front of it, which is called the transit method. This scientific trick is more than 90 percent accurate, but non-planetary bodies can show up as false positives — like when one star crosses in front of another in a binary system.

The new technique, called verification by multiplicity, allowed scientists to weed out instances that couldn’t possibly have been caused by eclipsing stars, eliminating the false-positive problem.

Verification by Multiplicity

The multiplicity method relies partly on the logic of probability. Distinguishing between a planet orbiting a star and a star orbiting  a star is difficult. But when a third body appears in a transit signal, the chance it is another star is less than 1 percent. A trio of orbiting stars likely wouldn’t line up the way Kepler likes, with two stars passing directly in front of the third, blocking its light and creating the dips that Kepler sees. So when astronomers see Keplerian evidence of a third body, they can be almost certain they’ve found more planets.

Kepler observed hundreds of stars with multiple planet candidates, and careful study of this sample allowed scientists to verify this next big batch of worlds.

“We built upon a lot of past work that has been vetted and reused by the community,” said Sara Seager, professor of Physics and Planetary Science at MIT. “It has a new aspect to it based on probability.”

The multiplicity technique will help scientists efficiently pore through the remaining two years of data from Kepler, which will likely yield hundreds more verified exoplanets.

Photo credit: Kepler Mission/NASA

CATEGORIZED UNDER: Space & Physics, top posts
  • TheBrett

    Even the smallest of the habitable zone planets is 1.8 times the radius of Earth. I’d be really iffy on whether that’s habitable unless we could somehow figure out its mass.

    • JWrenn

      Bigger isn’t that bad actually, in truth that would mean bigger gravity and thicker atmosphere as long as the distance to the sun is not that bad. It would mean the life there would be even more different from ours, but really that is to be expected. There is an outer limit but it is much higher than what life that has developed on earth could survive. Not an exact comparison but there is life at the bottom of the ocean under 1000 atmospheres of pressure. 1.8 times the gravity, if the mass is similar, is completely doable.

    • EverSubtle

      One step at a time. This is a gold mine of planets and information. We now can say that planetary systems with multiple planets around one star, like our own, are in fact common. Also that small planets, ranging from the size of Neptune to the Earth, make up the majority of planets in our galaxy
      I can’t wait till the next step is taken.

    • tomcharde

      For the record, out of the 1,715 confirmed exos there are actually a few in the hab zone that are smaller than 1.8x. For example: Kepler 62f = 1.41 Earth radii.

      Side note on ability to predict habitability… MIT recently announced a breakthrough technique for measuring planetary mass, which should be a big help when implemented. (Google “MIT planetary mass”.)

  • hammy__hamster

    Nice explanation of the technique (much, much clearer than the stuff about lions and lionesses that Nasa put out).

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