"A chthonian planet (k'THAW-nee-uhn, sometimes misspelled 'cthonian') is a class of planets that were formerly gas giants who lost their atmosphere due to close proximity to their star, which is called hydrodynamic escape. The remaining rocky or metallic core thus resembles a terrestrial planet in many ways. Montague II is an example of a planet whose atmosphere has been stripped away by stellar wind."@en . . . "Chthonian planet"@en . . "A chthonian planet (k'THAW-nee-uhn, sometimes misspelled 'cthonian') is a class of planets that were formerly gas giants who lost their atmosphere due to close proximity to their star, which is called hydrodynamic escape. The remaining rocky or metallic core thus resembles a terrestrial planet in many ways. Montague II is an example of a planet whose atmosphere has been stripped away by stellar wind."@en .