Astronomers have found an exoplanet about 1,360 light years away, very close to its star, and its clouds consist of vaporized rock.
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The planet is called WASP-178b, and it orbits WASP-178, a young, white star twice the mass of the Sun, in an extremely short orbit of just 3.3 days. At this close, temperatures rise in the gaseous world, so hot that it is classified as a “superhot Jupiter”, perhaps the most dangerous type of exoplanet we know.
A new study of the weather in this outer world has identified, for the first time, silicon monoxide (SiO) in the planet’s atmosphere, giving us new insight into these truly alien worlds.
“We still don’t have a good understanding of weather in different planetary environments,” said astrophysicist David Singh of Johns Hopkins University.
He added, “When you look at Earth, all our weather forecasts are still fine-tuned to what we can measure. But when you go to a distant exoplanet, you have limited predictive powers because you haven’t built a general theory of how everything in the atmosphere works together and responds.” to harsh conditions.
Noting that the hot Jupiter planets in particular are very fascinating and ready for study. As the name suggests, these worlds are gas giants, such as Jupiter, but they are also very hot, because they orbit in very close orbits with their stars, some of them wandering in less than a day.
Pointing out that it constitutes an interesting mystery and could not have formed in its current orbit, because gravity, radiation and intense stellar winds must prevent the gas from clumping together.
He explained that however, more than 300 hot Jupiters have been discovered so far, and astronomers believe that they are forming away from their stars, and migrating inward. The mass of WASP-178b is about 1.4 times the mass of Jupiter, and about 1.9 times its size.
Affected by the heat of its star, the outer planet reaches temperatures of 2450 K (2177 degrees Celsius, or 3950 degrees Fahrenheit).
This temperature is the ideal spot for detecting vaporized silicates, as theoretical studies have shown that silicon monoxide is expected to be detectable above 2000 K.
A team of scientists led by Singh and colleague Josh Luthringer of Utah Valley University used the Hubble Space Telescope to obtain the spectrum of WASP-178b, and found a signal unlike any before. According to their analysis, it turned out to be silicon and magnesium
In their paper, they wrote: “Silicon monoxide, in particular, has not been previously, to our knowledge, detected in exoplanets, but the presence of silicon monoxide in WASP-178b is consistent with theoretical predictions as the predominant species that carries silicon at high temperatures. “.
WASP-178b, as it is known on all hot Jupiters, is tidal-bound to its star, meaning that one side faces the star permanently, on perpetual day, and the other stays away at perpetual night.
This results in a large temperature difference between the two hemispheres of the outer planet
On the night side of an exoplanet, it may be cold enough for vapors to condense into clouds that fall deep into the atmosphere, before returning to the night side where the minerals evaporate again.
The researchers couldn’t see any sign of this condensation on the WASP-178b separator, the line that separates day from night. But the results suggest that silicon monoxide may be present on the other exoplanets whose final observations are more visible, WASP-76b.
And if rock rain is on an exoplanet, this might be the place to find it.
The team’s results also show that we’re getting better at looking at the mysterious atmospheres of distant worlds. This bodes well when looking at exoplanets that are smaller and farther from their stars.
“If we can’t figure out what’s happening on super-hot Jupiter, where we have strong, reliable observational data, we won’t have a chance to find out what’s happening in the weaker spectra of observing terrestrial exoplanets,” Loringer said. “This is a test of our techniques that allow us to build a general understanding of the properties physical activities such as cloud formation and atmospheric structure