Alien planet’s evaporating atmosphere revealed
The planet HD 189733b orbits 10 times closer to its star than Mercury is to the sun. As a result, the alien world keenly feels the violent effects from its parent star.
Based on HD 189733b’s distance from its star, which is cooler and smaller than the sun, astronomers calculated that the temperature of the outermost region of the planet’s atmosphere should be around 2,240 degrees Fahrenheit (1,227 degrees Celsius).
But by using the Hobby-Eberly Telescope at the University of Texas at Austin to take a direct measurement of the hot, or excited, hydrogen in the atmosphere, Jensen and his team pegged the temperature at a whopping 468,000 degrees Fahrenheit (260,000 degrees Celsius), more than 10 times hotter than expected.
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