Extrasolar Planets
See also: Extrasolar planet#Atmosphere
Two planets outside the solar system have been observed to have atmospheres. The first observed extrasolar planetary atmosphere was made in 2001. Sodium in the atmosphere of the planet HD 209458 b was detected during a set of four transits of the planet across its star. Later observations with the Hubble Space Telescope showed an enormous ellipsoidal envelope of hydrogen, carbon and oxygen around the planet. This envelope reaches temperatures of 10,000 K. The planet is estimated to be losing (1-5)×108 kg of hydrogen per second. This type of atmosphere loss may be common to all planets orbiting Sun-like stars closer than around 0.1 AU.
In addition to hydrogen, carbon, and oxygen, HD 209458 b is thought to have water vapor in its atmosphere. Water vapour has also been observed in the atmosphere of HD 189733 b, another hot gas giant planet.
Read more about this topic: Extraterrestrial Atmospheres
Famous quotes containing the word planets:
“Marriage is the clue to human life, but there is no marriage apart from the wheeling sun and the nodding earth, from the straying of the planets and the magnificence of the fixed stars.”
—D.H. (David Herbert)