News Release Archive:

News Release 42 of 1032

June 24, 2015 01:00 PM (EDT)

News Release Number: STScI-2015-17

Hubble Sees a 'Behemoth' Bleeding Atmosphere Around a Warm Neptune-Sized Exoplanet

June 24, 2015: Astronomers using NASA's Hubble Space Telescope have discovered an immense cloud of hydrogen dubbed "The Behemoth" bleeding off a planet orbiting a nearby star. The enormous, comet-like feature is about 50 times the size of the parent star. The hydrogen is evaporating from a warm, Neptune-sized planet, due to extreme radiation from the star. A phenomenon this large has never before been seen around any exoplanet. It may offer clues to how Super-Earths — massive, rocky, versions of Earth — are born around other stars through the evaporation of their outer layers of hydrogen. Finding "The Behemoth" could be a game-changer for characterizing atmospheres of the whole population of Neptune-sized planets and Super-Earths in ultraviolet observations.

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Illustration Credit: NASA, ESA, and G. Bacon (STScI)

Science Credit: NASA, ESA, and D. Ehrenreich (Observatory of the University of Geneva)