Smell of rotten eggs on the hot Jupiter closest to Earth

8 Jul. () –

The atmosphere of HD 189733 b, a Jupiter-sized gas giant, has traces of hydrogen sulfide, a molecule that emits a stench similar to that of rotten eggs.

A new study from Johns Hopkins University using data from the James Webb Space Telescope also offers scientists new clues about how sulfur, a building block of planets, might influence the interiors and atmospheres of gaseous worlds beyond the solar system. The findings are published in Nature.

“Hydrogen sulfide is an important molecule that we didn’t know was there. We predicted it would be there and we know it’s there on Jupiter, but we hadn’t really detected it outside the solar system,” said Guangwei Fu, a Johns Hopkins astrophysicist who led the research.

“We’re not looking for life on this planet because it’s too hot, but finding hydrogen sulfide is a step toward finding this molecule on other planets and better understanding how different types of planets form.”

In addition to detecting hydrogen sulfide and measuring total sulfur in HD 189733 b’s atmosphere, Fu’s team precisely measured the planet’s main sources of oxygen and carbon: water, carbon dioxide and carbon monoxide.

“Sulfur is a vital element for building more complex molecules and, like carbon, nitrogen, oxygen and phosphate, scientists need to study it further.” to fully understand how planets form and what they are made of“Fu said.

64 LIGHT YEARS AWAY

At just 64 light-years from Earth, HD 189733 b is the closest “hot Jupiter” astronomers can observe passing in front of its star, making it a benchmark planet for detailed studies of exoplanetary atmospheres since its discovery in 2005, Fu said.

The planet is about 13 times closer to its star than Mercury is to the Sun and takes just two Earth days to complete one orbit. It has scorching temperatures of 926 degrees Celsius and is known for its cruel weather, which includes the rain of glass flying sideways in winds of 2,760 kilometers per hour.

Just as it did in detecting water, carbon dioxide, methane and other critical molecules on other exoplanets, Webb gives scientists another new tool to track hydrogen sulfide and measure sulfur on gas planets outside the solar system.

“Let’s say we study 100 other hot Jupiters and they’re all sulfur-enhanced. What does that say about how they were born and how they form differently compared to our own Jupiter?” Fu said.

The new data also ruled out the presence of methane in HD 189733 b with unprecedented precision and infrared wavelength observations from the Webb telescope, which contradicts previous claims about the abundance of that molecule in the atmosphere.

“We had been thinking that this planet was too hot to have high concentrations of methane, And now we know that this is not the case,” said Fu.

The team also measured levels of heavy metals similar to those on Jupiter, a finding that could help scientists answer questions about how a planet’s metallicity correlates with its mass, Fu said.

Less massive ice giant planets like Neptune and Uranus contain more metals than are found in gas giants like Jupiter and Saturn, the largest planets in the solar system. The higher metallicities suggest that Neptune and Uranus accumulated more ice, rock, and other heavy elements relative to gases like hydrogen and helium during early periods of formation. Scientists are testing whether that correlation also holds for exoplanets, said Fu.

“This planet with the mass of Jupiter is very close to Earth and has been very well studied. Now we have this new measurement to show that, in fact, the concentrations of metals it has They provide a very important anchor point for this study of how a planet’s composition varies with its mass and radius.“Fu said.

“The findings support our understanding of how planets form by creating more solid material after the initial formation of the core.” and then they are naturally enriched with heavy metals.”

In the coming months, Fu’s team plans to track sulfur in more exoplanets and figure out how high levels of the compound might influence how close they form to their parent stars.

“We want to know how these types of planets got there, and understanding its atmospheric composition will help us answer that question,” said Fu.