"Atmosphere of Alien Super-Earth Revealed for First Time"
Clara Moskowitz, Space.com (December 1, 2010)
"The first-ever analysis of the atmosphere of an alien planet classified as a so-called 'super-Earth' has revealed a distant world that is likely covered with either water vapor or a thick haze, scientists announced today (Dec. 1).
"The exoplanet GJ 1214b, which orbits a star 40 light-years from Earth, offers astronomers a unique chance to study its atmosphere because it passes directly in front of its parent star from Earth's line of sight. That means that once an orbit, the star's light is filtered as it passes through the planet's atmosphere on its way to Earth, taking with it an imprint from the chemicals there. [Illustration of alien planet GJ 1214b]
" 'We're trying to get at: What's the main component of this planet's atmosphere?' said lead researcher Jacob Bean, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
"GJ 1214b is called a super-Earth because it is larger than our home planet but smaller than gas giants like Jupiter and Saturn. It was first discovered in 2009 and has been studied ever since...."
"...Rather than find a signal crawling with interesting elements, the scientists discovered that GJ 1214b's atmosphere bears a relatively flat, featureless signature.
" 'That might seem a bit boring, but that's actually a very powerful constraint,' Bean told SPACE.com.
"It means, for example, that the exoplanet's atmosphere can't contain much hydrogen, which typically leaves a strong feature in the spectrum of light coming from a planet.
"The astronomers concluded that the alien world's atmosphere is most likely dominated by water vapor or blanketed by a haze of clouds that is blocking other chemicals underneath.
" 'This isn't a definitive result, but it's very exciting,' Bean said. 'It points the way toward the future.'..."
This is actually quite exciting news.
GJ 1214b isn't the sort of "class M" planet that the old Star Trek series: many of which looked an awful like southern California, in the Los Angeles area. Which is almost another topic.
GJ 1214b is big - about 2.4 times the diameter of Earth, the Space.com article says - and, since it seems to be made out of roughly the same materials as Earth, the surface gravity would be distinctly uncomfortable. Sort of like walking with somebody sitting on your shoulders - who was carrying a pre-teen child.
The Lemming's no physiologist - but my guess is that sore feet would be among the least of one's problems, on a visit to GJ 1214b.
The size of the planet might make it a friendlier place for life than Earth, though. Some researchers think that maybe Earth is about as small as a planet can be - and still have conditions that let life develop. (December 5, 2009, January 13, 2008)
The latest news about GJ 1214b's atmosphere is very far from 'proof' that there's water there. On the other hand, it shows that the place has an atmosphere - and one that's not the sort of hydrogen-rich mix we're used to seeing on heavy planets.
- "Posts About the Gliese 581 Planetary System: Including Gliese 581g"
(October 14, 2010)
- "Life Around a Red Dwarf Star? Could be"
(July 7, 2010)
- "Another Super-Earth: Probably With Water, Possibly With Strange Chemistry"
(December 17, 2009)
- "Earth May Not Be a 'Class M' Planet"
(December 5, 2009)
- "Plate Tectonics, CO2, and Life on Other Planets"
(January 13, 2008)