The Milky Way in the dark night sky with the illuminating stars, part of the galaxy that contains our Solar System as seen from a sandy beach in Halkidiki, Greece, on August 2020. On a hellish planet where liquid iron rains, a molecule resembling ozone has been found in the atmosphere. NICOLAS ECONOMOU/NURPHOTO/GETTYIMAGES
An ozone-like chemical has been detected in the atmosphere of a hellish planet where it rains liquid iron.
The alien world is shrouded in thick clouds that interact with the light of its parent star – creating vanadium oxide.
It is the first time the metallic element has been detected on an exoplanet.
The reaction mirrors the natural layer of gas in Earth’s upper atmosphere that protects us from harmful ultraviolet radiation from the sun.
Lead author Stefan Pelletier, a Ph.D. student at Montreal University in Canada, said: “This molecule plays a similar role to ozone in Earth’s atmosphere.
“It’s extremely efficient at heating up the upper atmosphere. This causes the temperatures to increase as a function of altitude, instead of decreasing as is typically seen on colder planets.”
The gas giant named WASP-39b lies 634 light-years away in the constellation of Pisces.
It orbits only 4.3 million miles away from its parent star – about 12 times closer than Mercury is to the sun.
Temperatures at the surface reach more than 4,400°F – enough to vaporize iron which falls during windstorms of 10,000mph.
In the most detailed study of its kind to date eleven chemical elements were identified in the atmosphere of the planet.
They include rock-forming elements whose abundances are not even known for Jupiter or Saturn.
The international team used a scanner on the Gemini-North Telescope near the summit of Hawaii’s Mauna Kea volcano.
Pelletier said: “Truly rare are the times when an exoplanet hundreds of light years away can teach us something that would otherwise likely be impossible to know about our own Solar System. This is the case with this study.”
With a mass similar to that of Jupiter, but almost six times bigger by volume, WASP-39b is described as “quite puffy.”
It was discovered a decade ago by the Wide Angle Search for Planets (WASP) program.
Co-author Professor Bjorn Benneke, also from Montreal, said: “We recognized the powerful new MAROON-X spectrograph would enable us to study the chemical composition of WASP-76b with a level of detail unprecedented for any giant planet.”
The study in Nature sheds fresh light on the presence and abundance of rock-forming elements in giant planets in our own cosmic backyard.
On cold planets like Jupiter, for instance, they are lower in the atmosphere and impossible to detect.
Many in the exoplanet’s atmosphere – such as manganese, chromium, magnesium, vanadium, barium and calcium – match those of its host star as well as of our own sun very closely.
They are the direct product of the Big Bang, followed by billions of years of stellar nucleosynthesis, so scientists measure roughly the same composition in all stars.
It is, however, different from the composition of rocky planets like Earth, which are formed in a more complex manner.
The results indicate giant planets could maintain an overall composition that reflects that of the protoplanetary disc from which they formed.
But other elements were depleted in the planet compared to the star.
Pelletier said: “These elements that appear to be missing in WASP-76 b’s atmosphere are precisely those that require higher temperatures to vaporize, like titanium and aluminum.
“Meanwhile, the ones that matched our predictions, like manganese, vanadium, or calcium, all vaporize at slightly lower temperatures.”
Depending on an element’s temperature of condensation, it will be in gas form and present in the upper part of the atmosphere or condense into liquid form, where it will sink to deeper layers.
When in gas form, it plays an important role in absorbing light and can be seen in astronomers’ observations. When condensed, it cannot be detected by astronomers and becomes completely absent from their observations.
Pelletier said: “If confirmed, this finding would mean that two giant exoplanets that have slightly different temperatures from one another could have very different atmospheres.
“Kind of like two pots of water, one at -1°C that is frozen, and one that is at +1°C that is liquid. For example, calcium is observed on WASP-76 b, but it may not be on a slightly colder planet.”
It’s hoped the findings will improve our understanding of our own Solar System’s planets and how they came to be.
Benneke added: “Generations of researchers have used Jupiter, Saturn, Uranus, and Neptune’s measured abundances for hydrogen and helium to benchmark formation theories of gaseous planets.
“Likewise, the measurements of heavier elements such as calcium or magnesium on WASP-76 b will help further understanding the formation of gaseous planets.”
Produced in association with SWNS Talker
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