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Surprising Science

Kepler Finds Its Smallest Exoplanet To Date

Kepler 37-B is about the size of our moon, yet is a little too close to its parent star for human comfort.

What’s the Latest Development?

NASA’s Kepler space telescope has located a solar system that contains the smallest exoplanet found to date. Labeled Kepler-37b, it’s about the size of Earth’s moon, and orbits its parent star, Kepler-37, once every 13 days. As the innermost of the three planets in the system, it’s estimated to have a rocky surface, a temperature of about 800 degrees Fahrenheit, and no atmosphere or water. The other two planets, 37c and 37d,  orbit the star every 21 and 40 days respectively.

What’s the Big Idea?

Until now, many of the exoplanets discovered by Kepler have been Earth-sized or larger. NASA’s Thomas Barclay says the Kepler-37 system represents “a great diversity in planetary systems…This is the first time we’ve been able to probe the smallest range, smaller than anything we have in our solar system.” Kepler-37 is a yellow star that’s slightly smaller and cooler than our Sun, and resides about 210 light-years away. Astronomer Eric Ford says in a paper published in Nature that the discovery of this system “lends weight to the belief that planet occurrence increases exponentially with decreasing planet size.”

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Read it at Discovery News


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