Extreme ‘lava world’ and ‘iron planet’ have fastest years of any Kepler worlds

Astronomers working with data collected by the Kepler Space Telescope have turned up two alien worlds that orbit their parent stars in mere hours, putting these planets so close to their star that one is likely a lava world and the other may be composed almost entirely of iron!

The first of these two, called Kepler-78b, is an Earth-sized planet found orbiting a star slightly smaller, but similar to our own. It orbits so close in to that star that the surface is likely completely molten, and if anything were actually able to live in the extreme conditions there, it would tick off a year every 8.5 hours — that's nearly three of their years for every one of our days! Also, as an added bonus, Kepler-78b has also become the smallest planet that astronomers have actually been able to detect light from, and examining that light will be able to tell them even more about the planet's properties.

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The second planet, which hasn't yet been confirmed, is currently named KOI 1843.03 (KOI stands for 'Kepler Object of Interest'). It orbits a star about half the size of our Sun, and its year is half as long as Kepler-78b's — roughly 4.25 hours. Orbiting so quickly, and thus so close to its star, it must be made of some pretty tough material to avoid being torn to shreds by its star's gravity, and astronomers figure that it is likely almost entirely made of iron!

Both of these planets were discovered using the Kepler Space Telescope's 'transit' method, and they were written up in two papers (here and here) by researchers at MIT, Caltech, the Harvard Smithsonian Astrophysical Observatory, and the Niels Bohr Institute in Copenhagen.

So far, Kepler's observations have netted over 130 confirmed planets in 78 different star systems. There are over 3,200 other 'objects of interest' still to be examined, and there is still plenty of data left to be sifted through.

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These two planets are a great example of what Kepler still has to offer. The telescope's transit-hunting mission may be over due to the technical problems it's suffered, but it collected so much data during its mission we'll still be making awesome discoveries from it all for years to come.

If you want to get in on the excitement of finding these alien planets, the people at Planet Hunters are always looking for more citizen scientists to help in the search!

(Image courtesy: Cristina Sanchis Ojeda)

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