A chthonian planet ( /ˈkθoʊniən/, sometimes misspelled 'cthonian') is a hypothetical class of celestial objects resulting from the stripping away of a gas giant's hydrogen and helium atmosphere and outer layers, which is called hydrodynamic escape. Such atmospheric stripping is a likely result of proximity to a star. The remaining rocky or metallic core would resemble a terrestrial planet in many respects.
HD 209458 b is an example of a planet that is in the process of having its atmosphere stripped away, though it is not itself a chthonian planet nor is it expected to become one in the near future.
COROT-7b may be the first chthonian planet discovered, followed by Kepler-10b.
Chthonia (from Greek: χθων) means "of the Earth". The term was coined by Hébrard et al., since the term chthonian generally refers to Greek deities from the infernal underground.
Famous quotes containing the words chthonian and/or planet:
“It is not menstrual blood per se which disturbs the imagination—unstanchable as that red flood may be—but rather the albumen in the blood, the uterine shreds, placental jellyfish of the female sea. This is the chthonian matrix from which we rose. We have an evolutionary revulsion from slime, our site of biologic origins. Every month, it is woman’s fate to face the abyss of time and being, the abyss which is herself.”
—Camille Paglia (b. 1947)
“And so I look on those sentiments which make the glory of the human being, love, humility, faith, as being also the intimacy of Divinity in the atoms; and, that, as soon as the man is right, assurances and previsions emanate from the interior of his body and his mind; as, when flowers reach their ripeness, incence exhales from them, and, as a beautiful atmosphere is generated from the planet by the averaged emanations from all its rocks and soils.”
—Ralph Waldo Emerson (1803–1882)