The signature of hot hydrogen in the atmosphere of the extrasolar planet HD 209458b

  title={The signature of hot hydrogen in the atmosphere of the extrasolar planet HD 209458b},
  author={Gilda E. Ballester and David K. Sing and Floyd Leigh Herbert},
About ten per cent of the known extrasolar planets are gas giants that orbit very close to their parent stars. The atmospheres of these ‘hot Jupiters’ are heated by the immense stellar irradiation. In the case of the planet HD 209458b, this energy deposition results in a hydrodynamic state in the upper atmosphere, allowing for sizeable expansion and escape of neutral hydrogen gas. HD 209458b was the first extrasolar planet discovered that transits in front of its parent star. The size of the… 


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