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Hot Planet

October 13, 2015

The planet known as 55 Cancri e would not be a fun spot for a vacation. Giant volcanoes may cover much of its surface, belching out enough ash and gas to sometimes almost block its sun from view.

The planet was discovered more than a decade ago by astronomers at McDonald Observatory. It orbits 55 Cancri, a star that’s 40 light-years away in Cancer, the crab. The constellation is high in the east at first light.

Later observations showed that 55 Cancri e is a “super Earth” — a rocky world bigger and heavier than our own. It’s only about one-and-a-half million miles away from its star. At that range, it’s locked so that the same hemisphere always faces the star, just as the same hemisphere of the Moon always faces Earth. Not surprisingly, that hemisphere is extremely hot. In fact, its rocky surface may be partially molten.

Researchers used Spitzer Space Telescope to keep an eye on the planet for about three years. They found that the dayside temperature seemed to vary by a couple of thousand degrees.

One possible explanation for the change is massive volcanoes. At times, they may belch out enough gas and ash to partially obscure the planet’s surface. From afar, that would make the planet look cooler even if it’s not. So 55 Cancri e may be a world of molten rock, giant volcanoes, and clouds of volcanic debris thick enough to partially blot out its nearby star.

We’ll have more about exoplanets tomorrow.

Script by Damond Benningfield, Copyright 2015

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