Scroll to top

Planet similar to Jupiter but with a cloud-free atmosphere

Can you picture Jupiter with none observable clouds or haze? It isn’t easy since Jupiter’s latitudinal cloud bands and its Great Red Spot are iconic visual features in our system. Those features are caused by upswelling and descending gas, mostly ammonia. After Saturn’s rings, Jupiter’s cloud forms are probably the foremost recognizable feature within the system.
Now astronomers with the middle for Astrophysics | Harvard & Smithsonian (CfA) have found a planet similar in mass to Jupiter, but with a cloud-free atmosphere.
These planets are scarce, and astronomers think only about 7% of exoplanets are like this. the invention allows scientists to review how they form. Without clouds within the way, a clearer view awaits.
The team of astronomers behind the finding published their leads to The Astrophysical Journal Letters. The title is “Evidence of a transparent Atmosphere for WASP-62b: the sole Known Transiting Jovian planet within the JWST Continuous Viewing Zone.” Lead author of the study is Munazza Alam, a graduate student at the CfA. WASP-62b is that the nearest planet to WASP-62, a main-sequence star almost 600 light-years from Earth. 62b is that the only planet within the system which is about half as massive as Jupiter, and orbits WASP-62 in about 4.5 days. It’s about 1.4 times as large as Jupiter. It falls squarely into the category of Hot Jupiters, with a mean temperature of about 1330 K (1057 C; 1934 F.)

The planet’s temperature, size, and density properties aren’t rare. What’s rare is that the cloudlessness of its atmosphere. and therefore the exoplanet’s atmosphere is of interest to steer author Alam. during a handout, Alam said, “For my thesis, I even have been performing on exoplanet characterization. I take discovered planets, and that i follow abreast of them to characterize their atmospheres.”
The WASP name comes from the Wide Angle look for Planets (WASP) South. the earth was first discovered in 2012 and was one among seven Hot Jupiters found at an equivalent time.
WASP-62b was discovered with WASP, but Alam and her colleagues used the Hubble to review it more closely. “I’ll admit that initially, I wasn’t too excited about this planet,” Alam said. “But once I began to take a glance at the info, I got excited.”
Using spectroscopy, they watched closely because the planet transited ahead of its star 3 times, trying to find potassium and sodium. because the starlight skilled the planet’s atmosphere they identified sodium’s complete spectroscopic signature, but no potassium. The sodium signature indicates them that the atmosphere was clear. Alam said that this is the proof that we are seeing a transparent atmosphere.

In an email Alam explained in detail about the team’s spectroscopic findings and what they mean.
The focus on potassium and sodium is predicated on a few of things. Firstly, their spectra are easily visible in optical light. “The two spices sodium and potassium are readily observable in exoplanet atmosphere observations taken at optical wavelengths, and their presence or absence can help us infer if there happens to be any clouds or hazes in an exoplanet’s atmosphere,” Alam said.
Sodium and potassium also play a task in exoplanet atmospheres, though the small print aren’t clear. “Sodium and potassium are two elements that play a stimulating – yet not well understood – role within the atmospheric physics and chemistry of exoplanets,” Alam explained. She also mentioned that sodium was the primary absorption feature identified in an exoplanet’s atmosphere.
The detection of sodium’s complete spectroscopic signature tells astronomers that the atmosphere is obvious, albeit there’s no thanks to see the atmosphere. “Clouds during a planet’s atmosphere will mask or obscure parts of the absorption line,” Alam explained. “when the clouds are not present, we will resolve the complete sodium signature – which has attributes like a tent-like shape with a peak at the core of the absorption feature and broad line wings. For our observations of WASP-62b, this is often the second time that we’ve observed the complete sodium feature (i.e., with its line wings) in an exoplanet and therefore the first time that we’ve done so from space.”

This figure from the study shows the Hubble Space Telescope Imaging Spectrograph data for WASP-62b and thus the sole other known exoplanet with a transparent atmosphere, WASP-96b. Both exoplanets feature like the prominent pressure-widen wings of the Na D-lines at 0.59? m. Perceiving the sodium spectrum with wings tells that both planets have clear atmospheres. WASP-96b also depicts the presence of lithium and potassium.
But the whole sodium signature does quite tell us that the exoplanet’s atmosphere is cloud-free. It can help explain what proportion sodium there’s and indicate what other elements are within the atmosphere.
It not only tells us that the atmosphere is obvious but also it also can help us to constrain really precise abundances (quantities) of sodium – also as other elements that are present within the planet’s atmosphere,” Alam said. These abundances are helpful in calculating the key quantities which will help us trace back the origins and evolution of this planet.

There’s clearly something different happening when a cloud-free planet forms. Since there are so few of them, astronomers are only at the start of studying them. the sole other cloud-free exoplanet that we all know of is that the hot Saturn named WASP-96b, found in 2018.
It’ll be up to the James Webb Space Telescope to look at this exoplanet’s atmosphere more closely. And its clear atmosphere make that prospect even more exciting. The Webb’s advanced observing capabilities mean it should be ready to identify even more of the chemical constituents in WASP-62b’s atmosphere.
It’ll have two small continuous viewing zones (CVZ) because of the JWST’s orientation and position in space. They’re meeting on each pole of the ecliptic. WASP-62b is in one of Webb’s CVZs. and because of that fortune has been smiling on Alam and other exoplanet scientists.

The team of researchers even estimated what the JWST might find in 62b’s atmosphere. In their paper they write that we predict that JWST observations of WASP-62b, within the scope of the ERS program, can conclusively detect Na (12.1?), H2O (35.6?), FeH (22.5?), SiH (6.3?), NH3 (11.1?), CO (8.1?), CO2 (9.7?), and CH4 (3.6?). They also say that the JWST offers precise constraints on the abundance of chemicals within the atmosphere.

“In making JWST, identifying targets that are cloud-free/haze-free is important for mobilizing community efforts to see the simplest planets for detailed atmospheric follow-up. Although alternative targets have since been suggesting, WASP-62 is that the only star within the JWST CVZ with a known transiting giant planet that’s bright enough for high-quality atmospheric characterization via transit spectroscopy.” The James Webb Space Telescope is scheduled to launch at the top of October 2021.