A team of researchers, coordinated by astrophysicist Graham Lee, from the University of Saint Andrews, in the United Kingdom, has succeeded in determining the structure and chemical composition of the clouds of the exoplanet HD 189733b , located 64 light years away. This world is the closest known hot Jupiter to Earth, a type of object similar to the gas giants of our own system but orbiting very close to its star. In the case of HD 189733b, it is a K-type orange dwarf . When it passes in front of it, it causes a three percent decrease in brightness.
Lee and his colleagues have developed a 3D hydrodynamic model that is based on cloud mass formation processes. Thus, they have been able to find out that most of the particles that make up the clouds of this exoplanet measure less than 0.5 microns , a unit that is equivalent to one thousandth of a millimeter. The largest, up to 1 millimeter, are found in the densest regions of the atmosphere, deep inside it.
Regarding its chemical composition, a great abundance of silicates , such as enstatite and olivine, has been found at medium and high latitudes. In the equatorial regions, silicon monoxide and dioxide appear to be the most widespread compounds. However, according to the scientists, changes in thermochemical conditions mean that the combinations can vary significantly. Even so, they have learned that these clouds made up of minerals can remain in the atmosphere for years without disintegrating .
Now, this team of experts hopes that their new model can shed some light on the study of the atmospheres of other extrasolar worlds, specifically the aforementioned hot Jupiters .
Image: NASA / ESA / M. Kornmesser
