Using state-of-the-art technology, a team of astronomers at the Keck Observatory has detect water in the atmosphere of the extrasolar planet 179 light years from us. This is about HR 8799 c, in the solar system that revolves around the star HR 8799.
In 2008, scientists announced that, using the Keck and Gemini telescopes, they had directly observed three exoplanets around the star mentioned earlier: HR 8799b, c and d. Then, in 2010, they reported the discovery of the fourth planet, HR 8799 e.
Now, the study presented is based on data obtained in 2008. New observations with direct images are from HR 8779 c, a young gas giant planet about seven times the mass of Jupiter, our solar giant, which takes 200 years in orbiting its star.
Data obtained on this occasion, according to the author, will confirm the presence of water in the atmosphere and also absence of methane inside it.
— technology —
To reach this conclusion, the researchers used a a combination of two Keck telescope technologies. The first is adaptive optics, which counteracts the diffuse effects of Earth's atmosphere. The second is a spectrometer at the Keck 2 telescope called Echelle Near Infrared Cryogenic Spectrograph (NIRSPEC), a high-resolution spectrometer that works with infrared light.
According to Dimitri Mawet, professor at Caltech and co-author of the study, he explained:
"This type of technology is exactly what we want to use in the future to look for signs of life on a planet similar to Earth. We are not there yet, but we are moving forward."
— Research —
The new discovery was published in the journal Astronomy Journal. The lead author is Ji Wang, a former postdoctoral associate at Caltech and now an assistant professor at Ohio State University.
So far, astronomers have directly photographed more than a dozen extrasolar planets. The HR 8799 system is the first multi-planet system from which images have been obtained directly. But this is only the first step in this study.
Once taken, images can be analyzed for chemical composition in the atmosphere. This is where spectroscopy comes in. In this case, NIRSPEC's fine skills are key.
NIRSPEC is an instrument that operates in the L infrared band. This is a type of infrared light with a wavelength of about 3.5 micrometers and a spectrum region with large detailed chemical traces.
"The L band has been ignored before because the sky is brighter at this wavelength, if you are an alien with eyes aligned with the L band, you will see a very bright sky, it is difficult to see exoplanets through this. Veil," explained Mawet.
By combining bands with adaptive optics, they are able to make the most accurate planetary measurements, thus confirming the presence of water and the absence of methane.
With information from Universe Today and Busness Insider