Scientists found out that an exoplanet, located at 600000 billions of kilometers from our Earth, owns gas carbon and water vapor. 300 times more massive than our planet and with around 1000 degrees celsius, this exoplanet is called HD189733b and it circles around its star in a little more than 2 days only. Discovered in 2005 by the observatory of Haute-Provence (France) in the constellation of vulpecula (little fox), it is the most shining of the exoplanets (outside of our solar system) in which we can observe its transit – its passing in the front and in the back of its star. Big spatial telescopes with infrared spectrometers

allow scientifics to determine the composition of its atmosphere. Each gas in this planet absorb a length of a particular wave of the radiation emitted by this planet lighted by its sun.

So, in december 9, 2008, NASA announced to have detected, with the telescope Hubble, carbon dioxide (CO2) in the atmosphere of HD189733b but also carbon monoxide (CO) and methane (CH4) - in fact the first exoplanet with such characteristics.

Scientists said that the carbon dioxide could be linked to an activity biologic, as in Earth, in favorable conditions. The life is based on the chemistry of the carbon and this one is more easy to get from the carbonic gas than the methane or the carbon monoxide.

What it means ? Simply that one of the necessary ingredients for life exists in this planet but the second one is still missing, water in liquid. Scientists said that we can’t imagine the molecular diversity, essential for life, without carbon and without water liquid.

The point is that HD189733b doesn’t have water liquid but water vapor. This discovery has been found by another team with the telescope Spitzer and published it in the magazine Nature of december 11, 2008.

Other results from another research suppose that this planet can have a complex circulation atmospheric or a source of unknown internal heat. Since the discovery of the first exoplanet in 1995, the catalog has increased a lot and there are 333 listed extrasolar planet – up to date regularly on the exoplanet website.

This number doesn’t mean that they are the most in the outer space but simply that they are more easy to detect by the indirect method of the transit (variation of the star light when the planet passes in front of the stellar disc) or of the radial speed (periodic interval of the star position provoked by the planet).

February 12, 2009

 

Previous

Next