There are many interesting planets in the universe, such as supermercuries, mini-Neptunes, hot Jupiters and ultrahot Jupiters. Each celestial body in the latter type is located very close to its star, and its atmospheres contain clouds of vaporized heavy elements.
Such planets are WASP-76b and WASP-121b. In their atmosphere, astronomers have detected a heavy element that they did not expect to find, especially in the upper layers. This is barium.
It should be noted that calcium, titanium oxide, and vanadium oxide have been detected in WASP-76b’s gaseous shell, and vanadium, iron, calcium, chromium, sodium, magnesium, and nickel in WASP-121b.
Traces of barium have not been found in the atmosphere of any other exoplanet so far, so they were not looking for it either. Despite this, the analysis of the spectrum of the light reflected by it revealed the presence of the aforementioned metal. Scientists obtained this information by studying the transit of celestial bodies to the star, as well as by comparing the luminosity and the light of the planets.
WASP-76b and WASP-121b have orbital periods of 1.8 and 1.27 days due to their proximity to the star, and their masses are 0.92 and 1.18 Jupiter masses. This means that these gas giants have strong gravity, so heavy elements should be drawn to the lower layers, but they are not.
Scientists still do not know what mechanism keeps barium in the upper atmosphere. Understanding this and specifying their composition will provide us with valuable information about similar planets. For example, we now know that WASP-121b’s atmosphere is being vaporized by the impact of the star, suggesting that superhot Jupiters are short-lived.
Authors’ paper in Astronomy & Astrophysics.
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