Discovery of barium is surprising because heavy elements like barium are expected to quickly fall into the lower layers of the atmosphere
Scientists have detected barium in the upper atmosphere of two giant exoplanets for the first time, noted a new study. Barium, two and half times heavier than iron, is the heaviest-ever detected element.
These exoplanets are two ultra-hot Jupiters — WASP-76b and WASP-121b — which orbit their host stars WASP 76 and WASP 121, according to the study published in the journal Astronomy and Astrophysics September 6, 2022.
The former is about 640 light-years away from the Earth and the latter around 900 light-years away.
Ultra-hot Jupiters are a class of hot gaseous planets that matches the size of Jupiter. But they have short orbital periods, unlike Jupiter.
Both WASP-76b and WASP-121b complete one orbit in two days. Surface temperatures in these bodies reach as high as 1,000 degrees Celsius. These bodies have unique features owing to their high temperatures. For instance, WASP-76b experiences iron rain, the scientists said.
Scientists from Portugal, Spain, Switzerland, Italy and Germany detected barium using the European Southern Observatory’s Very Large Telescope located in the Atacama Desert, northern Chile.
The scientists confirmed the presence of hydrogen, lithium, sodium, magnesium, calcium, vanadium, chromium, manganese and iron in the atmosphere of the WASP-76 b, in addition to barium.
In WASP 121b, they confirmed the presence of lithium, sodium, magnesium, calcium, vanadium, chromium, manganese, iron and nickel.
Additionally, the team found elements such as cobalt and strontium. They also found indications of titanium in the exoplanet.
“Besides finding the expected elements, we found some other elements that we did not anticipate at all,” Tomás Azevedo Silva from the University of Porto, Portugal, told Down To Earth.
The presence of heavy elements at high altitudes in the atmospheres of ultra-hot Jupiters indicates that some unique atmospheric dynamics are at play.
This discovery of barium is surprising because heavy elements like barium are expected to quickly fall into the lower layers of the atmosphere, given these exoplanets have high gravity, co-author Olivier Demangeon said in a statement.
Barium salts are used in fireworks to generate green lights.
Silva said he does not understand why a heavy element like barium exists in the upper layers of the atmosphere. “It is puzzling and counterintuitive,” he added.
Astronomers will surely try to answer this mystery in the near future, he said. The researchers hope that their study encourages more researchers to explain the presence of these elements in the upper layers of the atmosphere.
“It may reveal some new dynamics inside the atmospheres or give us insights into the composition of these distant planets,” he added. Silva and his team will model these extreme atmospheres to better understand their structure, composition and dynamics.
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