methane detected in exoplanet's atmosphere

Paul Scott Anderson · #1 (**permalink**) 15-March-2008, 08:32 AM

The Hubble Space Telescope has reportedly found evidence of methane in the atmosphere of an exoplanet orbiting a distant star, the first ever such detection. While methane can be produced both biologically and geologically, the brief media advisory mentions that the planet is “too hot” for life (as we know it):

http://www.nasa.gov/home/hqnews/2008...Molecules.html

NASA will hold a media teleconference at 2:00 pm ET on Wednesday, March 19. When it starts, more information will be posted here:

http://hubblesite.org/news/2008/11

Paul

01101001 · #2 (**permalink**) 16-March-2008, 04:46 AM

ArXiv: Methane present in an extrasolar planet atmosphere; Mark R. Swain, Gautam Vasisht, Giovanna Tinetti (2008 February 8)

Quote:

Here we report on a near-infrared transmission spectrum of the planet HD 189733b showing the presence of methane. Additionally, a resolved water-vapour band at 1.9 microns confirms the recent claim of water in this object. On thermochemical grounds, carbon-monoxide is expected to be abundant in the upper atmosphere of hot-Jovian exoplanets; thus the detection of methane rather than carbon-monoxide in such a hot planet could signal the presence of a horizontal chemical gradient away from the permanent dayside, or it may imply an ill-understood photochemical mechanisms that leads to an enhancement of methane.

NewScientist: Organic molecules found on alien world for first time (2008 February 11)

Quote:

Organic molecules – in the form of methane – have been detected on a planet outside our solar system for the first time. The giant planet lies too close to its parent star for the methane to signal life, but the detection offers hope that astronomers will one day be able to analyse the atmospheres of Earth-like worlds.
Astronomers Mark Swain and Gautam Vasisht of Caltech in Pasadena, US, and Giovanna Tinetti of University College London, UK, used the Hubble Space Telescope to observe the giant planet HD 189733b, which is slightly more massive than Jupiter and lies 63 light years from Earth.
[...]
"Initially, that is surprising," says Sara Seager of MIT in Cambridge, US, who was not involved in the study. Because HD 189733b orbits very close to its parent star – just 10% of Mercury's distance from the Sun, it is very hot, with atmospheric temperatures of about 700° Celsius. "When the temperature is this high, the dominant form of carbon should be carbon monoxide, not methane," says Seager.
The authors suggest that some ill-understood chemical process might be responsible, either concentrating the methane in cooler parts of the atmosphere, or generating extra methane directly. Alternatively, the methane might simply mean that the planet happens to be very rich in carbon, Seager says.

See also topic Water Identified in Extrasolar Planet Atmosphere about HD 189733b.

TheKnowledge · #3 (**permalink**) 16-March-2008, 05:19 AM

Quote:

Originally Posted by Paul Scott Anderson

NASA will hold a media teleconference at 2:00 pm ET on Wednesday, March 19. When it starts, more information will be posted here:

http://hubblesite.org/news/2008/11

Paul

The second link came up with this error message:

"The news release you requested was not found. The link you followed may be incorrect, or the page has not been posted yet.

News items are posted on their official release dates. The latest news releases are located on the NewsCenter home page. The most recent news items are listed by date in the News Release Archive. If you fail to locate a current news item, please try again later."

Paul Scott Anderson · #4 (**permalink**) 16-March-2008, 05:49 PM

TheKnowledge,

As the media advisory at the first link already stated, the information will be posted at the second link when the media teleconference starts, on March 19...

See also the abstract posted by 01101001.

I saw no, zero, discussion of this in February, but the NASA media advisory was just posted now, on March 14.

Paul

01101001 · #5 (**permalink**) 19-March-2008, 06:55 PM

NASA News Audio Live Streaming

Quote:

2 p.m. EDT, Wednesday, March 19

NASA will hold a media teleconference to report on the first-ever detection of the organic molecule methane in the atmosphere of a planet orbiting a distant star.

Direct to conference: NASA audio conference (Real audio .ram) (active with classical music just before the conference)

Hubble site news materials (supposed to become active at the start of the briefing)

Edit: now working:

Ars Technica: Methane that is out of this world:

Quote:

The authors of an article in today's issue of Nature managed another form of measurement. They looked at light transmitted through the atmosphere of the imaginatively named planet HD 189733b. HD 189733b is a gas giant, comparable in size to Jupiter, that is 63 light years from Earth. By looking at transmission spectra, the authors were able to make the first identification of methane on a planet outside of our solar system.
[...]
They found that the observed absorption curve matched the absorption curves of methane and water vapor. This confirms the presence of water that was suggested in a Nature paper last year, and is the first identification of methane on any planet outside our solar system. Other gases that are expected to be present (e.g. ammonia and carbon monoxide) will not generate the absorption curve that was observed, thus the authors are confident that they have identified methane. It should be noted these other gases are probably present—indeed, carbon monoxide is probably the most abundant Carbon molecule in HD 189733b—but their abundance cannot be accurately determined from the present data.

Edit, 4 minutes after the hour: started

01101001 · #6 (**permalink**) 19-March-2008, 07:19 PM

I wasn't listening real hard, but this seems to be the same first-ever news hinted at in February, noted above, via arXiv and NewScientist. I guess making into Nature makes it worthy of a press conference.

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