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Can you imagine Jupiter without any observable clouds or haze? This is not easy as Jupiter’s occasional cloud bands and its large red dot are distinct visual features of our solar system. These properties are due to the rise and fall of gas, in particular ammonia. After the rings of Saturn, the cloudy forms of Jupiter are probably the most distinctive feature of the solar system.
Now astronomers with the Center for Astrophysics | Harvard and Smithsonian University (CfA) found a planet similar in mass to Jupiter, but with a clear atmosphere.
These planets are rare, and astronomers believe that only about 7% of exoplanets look like this. The discovery allows scientists to study how it formed. Cloudy on the road, a clearer view awaits you.
The team of astronomers behind the discovery published their findings in The Astrophysical Journal Letters. The title is “Evidence of Clear Atmosphere for WASP-62b: The Only Known Transit Gas Giant in JWST Continuous Viewing Area.” Lead author of the study is CfA graduate student Menzah Alam.
WASP-62b is the closest planet to WASP-62, which is a main sequence star 600 light years from Earth. 62b is the only planet in the system. It’s barely half the colossal size of Jupiter and orbiting WASP-62 in about 4.5 days. It is about 1.4 times the size of Jupiter. It falls directly into the category of hot Jupiters, with an average temperature of around 1330 K (1057 ° C; 1934 ° F).
The temperature, size and density characteristics of the planet are not uncommon. Rare is the absence of clouds in the atmosphere. The atmosphere of an exoplanet is of particular importance to the author’s direction. In a press release, a scientist said: “In my article, I worked on the characterization of exoplanets. I took the discovered planets, and I follow them to discover their atmospheres.
The name WASP comes from the South Wide Angle Planet Search (WASP). The planet was first discovered in 2012 and was one of seven hot planets found at the same time.
WASP-62b was discovered using WASP, but Alam and his colleagues used Hubble to study it more closely. “I admit that at first I was not very excited about this planet,” said Allam. “But once I started looking at the data, I got excited.”
Using spectroscopy, they closely monitored the planet’s passage past its star on three occasions, looking for potassium and sodium. As starlight passed through the planet’s atmosphere, they determined the full spectral signature for sodium, but not potassium. The sodium signature told them it was clear.
“It’s smoking proof that we see a clear atmosphere,” Alam said.
In an email with Universe Today, a scientist explained the team’s spectroscopy results and what they mean.
The concentration of potassium and sodium depends on several factors. First of all, its spectra are easily observable in optical light. Alam said: “Sodium and potassium are two types that can be easily observed in atmospheric observations of exoplanets taken at optical wavelengths, and their presence or absence can help us conclude if there are any clouds. Or fog in the atmosphere of an exoplanet.
Sodium and potassium also play a role in the atmospheres of exoplanets, although the details are unclear. “Sodium and potassium are two elements that play an interesting – but poorly understood – role in atmospheric physics and the chemistry of exoplanets,” one scientist explained. He also reported that sodium is the first absorption property identified in the atmosphere of an exoplanet.
The discovery of the full spectrum sodium fingerprint tells astronomers that the atmosphere is clear, although there is no way to see the atmosphere. Allam explained that “the clouds in the planet’s atmosphere will hide or obscure parts of the absorption line.” “In the absence of clouds, we can solve the entire sodium footprint – tent-shaped with a peak at the heart of the absorption function and large wings. For our observations of WASP-62b, this is the second time that we have observed the full sodium function (i.e. with its linear wings) in an exoplanet and the first time that we have done so from space.
But the full sodium footprint does more than tell us that an exoplanet’s atmosphere is cloud-free. This can help explain the amount of sodium and other elements in the atmosphere.
“Not only does this tell us that the atmosphere is clear, but it can also help us reduce the exact amounts (amounts) of sodium – as well as other elements in the planet’s atmosphere,” Elm said. “This abundance is useful for measuring key quantities that can help us trace the origins and evolution of this planet.”
Obviously, something different happens when a clear planet is formed. Since there are so few, astronomers are only beginning their study. The only cloudless exoplanet we know of is the hot planet Saturn, called WASP-96b, discovered in 2018.
It would be up to the James Webb Space Telescope to take a closer look at the atmosphere of this exoplanet. And its clear sky makes the possibility even more exciting. Webb’s advanced monitoring capabilities mean it should be able to identify more chemical components in the atmosphere of WASP-62b.
“In preparation for JWST, setting fog-free / fog-free targets is essential to mobilize community efforts to monitor the best planets for detailed atmospheric surveillance.”
From “Clear Atmospheric Evidence for WASP-62b: The Only Known Transiting Gas Giant in the JWST Continuous Viewing Area.”
Considering the direction and location of the JWST in space, it will have two Continuous Display Areas (CVZs). Concentrated at each pole of the ecliptic. Fortune is smiling at Alam and other scientists on exoplanets because WASP-62b is on one of Webb’s CVZs.
The research team even predicted what JWST might find in its 62b atmosphere. In their paper, they write: “We expect the JWST observations of WASP-62b, under the ERS program, to be able to conclusively detect Na (12.1).؟), H2O (35.6؟), FeH (22.5؟) ، SiH (6.3؟), New Hampshire3 (11.1؟) ، CO (8.1؟) ، CO2 (9.7؟) And CH4 (3.6؟). They also say that the planet Earth theory could have subtle restrictions on the abundance of chemicals in the atmosphere.
In their conclusion, the authors argued for a follow-up of the observations of WASP-62b with JWST.
“In preparation for JWST, the designation of fog-free / cloud-free targets is essential to mobilize community efforts to observe the best planets for detailed atmospheric monitoring. Although alternative targets have since been proposed, WASP-62 is the only star in JWST CVZ with a known transit giant planet bright enough for high-quality characterization of the atmosphere by transient spectroscopy.
The James Webb Space Telescope is expected to launch in late October 2021.
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