Astronomers using the NASA/ESA/CSA James Webb Space Telescope have detected trace amounts of hydrogen sulfide in the atmosphere of the Jupiter-sized exoplanet HD 189733b.
Artist's impression of hot Jupiter exoplanet HD 189733b. Image courtesy of Roberto Molar Candanosa / Johns Hopkins University.
HD 189733b is a hot gas giant with a hazy atmosphere composed mostly of hydrogen that lies about 63 light-years away in the constellation Vulpecula.
The planet is discovered It was discovered in 2005 by astronomers using two telescopes at the Observatory of Haute-Provence.
HD 189733b is just 1.2 times the size of Jupiter, but it orbits its parent star, HD 189733, very closely, completing one revolution around the star every 2.2 days.
“Hydrogen sulfide is a major molecule that we didn't know existed. We predicted it would be there, and we know it's on Jupiter, but we'd never actually detected it outside the solar system,” said Dr Guangwei Hu, an astrophysicist at Johns Hopkins University.
“Although we're not looking for life on this planet because it's too hot, the discovery of hydrogen sulfide is a stepping stone to finding this molecule on other planets and improving our understanding of how different types of planets form.”
“In addition to detecting hydrogen sulfide and measuring the total amount of sulfur in HD 189733b's atmosphere, we also precisely measured the main sources of oxygen and carbon on the planet: water, carbon dioxide, and carbon monoxide.”
“Sulfur is an essential element for building more complex molecules, and like carbon, nitrogen, oxygen and phosphate, scientists need to study it further to fully understand how planets are built and what they're made of.”
The Webb probe will give scientists new tools to track hydrogen sulfide and measure sulfur on gas giants outside our solar system, just as they have detected water, carbon dioxide, methane and other important molecules on other exoplanets.
“Let's say we study another 100 hot Jupiters and they're all enriched with sulphur. What does that say about how they came into being and how they formed differently compared to our Jupiter?” Dr Fu said.
The new data, delivered by the Webb Telescope at unprecedented precision and in infrared wavelengths, also rule out the presence of methane in HD 189733b's atmosphere, refuting previous claims that the molecule is abundant in the atmosphere.
“We thought the planet would be too hot for high concentrations of methane to exist, but it turns out that's not the case,” Dr Fu said.
Astronomers also measured Jupiter-like levels of heavy metals, a discovery that could help scientists answer questions about the correlation between a planet's metallicity and its mass.
“Low-mass ice giants like Neptune and Uranus contain more metals than gas giants like Jupiter and Saturn, the largest planets in the solar system,” Dr Fu said.
“High metallicity suggests that Neptune and Uranus accumulated more ice, rock and other heavy elements compared to gases such as hydrogen and helium early in their formation. Scientists are testing whether this correlation also holds true for exoplanets.”
“This Jupiter-mass planet is very close to Earth and has been very well studied. Now, our new measurements show that this planet's metal concentrations provide a very important anchor point for studies of how a planet's composition varies with its mass and radius.”
“This discovery supports our understanding of how planets form after the initial core is formed, creating more solid material that is then naturally enriched with heavy metals.”
Team result Published in the journal Nature.
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G. Hu othersA hydrogen sulfide and metal-rich atmosphere on a Jupiter-mass exoplanet. NaturePublished online July 8, 2024; doi: 10.1038/s41586-024-07760-y
Source: www.sci.news
