[HOT] : The clouds discovered on this exoplanet are very different from those on Earth

To detect their presence, an international team of scientists analyzed data from several telescopes: “We do not yet know their composition but we know that they are not made up of water droplets. “

An international team of scientists, led by astronomer Romain Allart from the University of Montreal, Canada, has detected the presence of “opaque clouds” on a distant exoplanet, called WASP-127b, a gas giant discovered in 2008 and some larger than Jupiter (1.3 times the size of our red giant). The discovery, fundamental for several purposes (also to understand the possibility of the presence of life or biological signatures on planets beyond the solar system), was presented in a study on Astronomical & Astrophysics published on the occasion of the ‘Europlanet Science Congress 2021, allowing to know some details of the atmosphere of one of the least known exoplanets.

WASP-127b is one of the so-called swollen planets, or hot planets of Jupiter which, unlike in the solar system, orbit in the opposite direction to its star, at a distance which is only 1 / 44 of that between the Earth and the Sun. 1.6 times smaller than that of Jupiter, which means that its atmosphere is somewhat thin and tenuous, perfect for analysis based on the light passing through it.

This light, evaluated using the combination of infrared data from the Hubble Space Telescope and optical data from the Espresso instrument of the Very Large Telescope on Earth, made it possible to detect the presence of sodium in the atmosphere but from “a much higher altitude. low than expected Researchers revealed. “In addition – Allart said – there were strong water vapor signals in the infrared, but none in the visible wavelengths. This implies that water vapor at lower levels is protected by opaque clouds at wavelengths visible but transparent in the infrared. ”.

The use of high-resolution absorption data made it possible to restrict the analysis to specific altitudes, until the detection of a layer of clouds “surprisingly low” And with an atmospheric pressure between 0.3 and 0, 5 millibar. “We do not yet know the composition of clouds, except that they are not composed of water droplets as on Earth – Allart added -. We are also puzzled as to why sodium is found in an unexpected place on this planet. Future studies will help us to better understand not only the atmospheric structure, but also the particularly fascinating WASP-12b. ”.

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