Penn State University astronomers discovered a “hot Jupiter” exoplanet that orbits very close to its parent star and whose atmosphere seems to “snow” sunscreen. Namely, its precipitations were determined to be composed of titanium oxide, one of the active ingredients in our sunscreen.
Besides this sunscreen snow itself, another bizarre feature of this planet is that titanium oxide can only be found on one side of the planet.
Sunscreen Snow, Sign of a Titanium Atmosphere?
This new exoplanet, named Keppler-13Ab, was analyzed with some help from the Hubble Space Telescope. It is one of the hottest exoplanets currently known, and the fact that it is close to its planet star makes it tidally locked. This means that one of the sides of the planet is always facing the star while the other is in permanent darkness.
As one side is blistering hot, the other seems to be extremely cold, this latter also being the side which experiences the snow falls. According to the latest Hubble observations, the night-side of the exoplanet revealed traces of a “cold trap”.
This is the name given to a “snow-out” process. Titanium oxide gas accumulations in the planet’s hotter upper atmosphere seem to be transported to the other, colder side by very powerful winds.
As they reach this area, the gas starts condensing and turns into crystalline flakes. As these form clouds, the sunscreen snow starts falling. This was also noted to get captured and trapped in Kepler-13Ab’s lower atmosphere by the exoplanet’s strong surface gravity.
The study team also noticed that this blistering exoplanet was unusual even among its fellow “hot Jupiters”. In contrast to the others, whose temperatures start rising as they increase in altitude, Kepler-13Ab has a cooler atmosphere at its higher elevations. This observation helped lead to the discovery of the sunscreen snowfalls.
“In many ways, the atmospheric studies we’re doing now on these gaseous ‘hot Jupiter’ kinds of planets are test beds for how we’re going to do atmospheric studies of terrestrial, Earth-like planets,” states Thomas Beatty, the lead author.
Detailed study findings are available in The Astronomical Journal.
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