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Friday March 25, 2011
measure the presence of water vapor in the exoplanet GJ 1214b, though the possibilities of life as we know it are nil.
Perhaps someday we can look back and see the steps that led us to detect life in some remote exoplanet. Since then our philosophical and scientific conceptions of what life is change. Some of these steps have been small and given one after another, with effort and tenacity of scientists who have gradually been winning their share of the ocean of ignorance.
Doppler was started detecting giant planets like Jupiter and then found what was called super-Earths. Of them came to know the orbital parameters of its orbit. The transit method enabled us to detect smaller planets and even measure its diameter. Remember that as the Doppler technique detects primarily the most massive planets, the transit technique does with those closest to the star. So statistical samples obtained in both cases are not representative of real people.
While all this was achieved, planetary formation models, structure Planetary and spectrometric have been providing new results. The outcome today is that we know hundreds of exoplanets, some of them with features that we had never imagined. But its composition is inferred that part of the time only through models, is rarely measured directly (although there is always a model behind any action.) In fact we can only know the atmospheric composition of these exoplanets, unless of course we travel there. But atmospheric composition can tell us a lot of opportunities there are conditions for life on a planet or even confirm its existence. To determine the composition of a planetary atmosphere we can assert spectrometry. Or by the light reflected by the gases of the atmosphere or because they absorb when placed in front of the disc from its star as our perspective.
a while ago measured the presence of certain gases in the atmosphere of an extrasolar planet Jupiter. Now it has managed to take a spectrum of an Earth-like "super-Earth" and confirmed the presence of water vapor in its atmosphere. For both measures has been used the Very Large Telescope, and Spitzer as MEarth mini-telescope project.
It GJ 1214b, exoplanet discovered in 2009 by MEarth that M star orbits in the constellation Ophiuchus. It has a very short orbital period, because it takes only 1.6 days to complete one orbit around its star. But this proximity to the star prevents the temperature is low enough to be habitable. Its diameter is 2.7 times the Earth and its mass 6.6 times that of Earth.
Previous results obtained previously, and not very good quality, could fit into a planetary model in which the planet would have an atmosphere of hydrogen and helium. They have now managed to eliminate that possibility with a statistical confidence of 99.99%. The second possibility was that the planet contains a large amount of elements heavier than hydrogen and helium. This possibility was confirmed when tested with a 99.97% confidence (3 σ) that its atmosphere is composed of 10% water vapor. The temperature, however, seems to be around 280 degrees Celsius according to the calculations.
According to the models of planet formation planet's atmosphere could be formed from two different scenarios. In the first, the atmosphere is formed during the process of global aggregation, this would lead to an enrichment of light gases such as hydrogen and helium. The second scenario would place the formation of this body beyond the line icing and then move toward the innermost orbit, creating an atmosphere rich in heavy elements to sublimate the ice. This result confirmed the second stage.
Neofronteras
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