Astronomers discover first cloudless, Jupiter-like planet
This marks the second time astronomers have ever observed a cloud-free exoplanet

Date:
January 22, 2021
Source:
Harvard-Smithsonian Center for Astrophysics
Summary:
Astronomers have detected the first Jupiter-like planet without
clouds or haze in its observable atmosphere.



FULL STORY ========================================================================== [Hubble Space Telescope | Credit: (c) dottedyeti / stock.adobe.com]
Hubble Space Telescope illustration (stock image).

Credit: (c) dottedyeti / stock.adobe.com [Hubble Space Telescope | Credit:
(c) dottedyeti / stock.adobe.com] Hubble Space Telescope illustration
(stock image).

Credit: (c) dottedyeti / stock.adobe.com Close Astronomers at the
Center for Astrophysics | Harvard & Smithsonian have detected the
first Jupiter-like planet without clouds or haze in its observable
atmosphere. The findings were published this month in the Astrophysical
Journal Letters.


========================================================================== Named WASP-62b, the gas giant was first detected in 2012 through the Wide
Angle Search for Planets (WASP) South survey. Its atmosphere, however,
had never been closely studied until now.

"For my thesis, I have been working on exoplanet characterization,"
says Munazza Alam, a graduate student at the Center for Astrophysics
who led the study. "I take discovered planets and I follow up on them
to characterize their atmospheres." Known as a "hot Jupiter," WASP-62b
is 575 light years away and about half the mass of our solar system's
Jupiter. However, unlike our Jupiter, which takes nearly 12 years to
orbit the sun, WASP-62b completes a rotation around its star in just four-and-a-half days. This proximity to the star makes it extremely hot,
hence the name "hot Jupiter." Using the Hubble Space Telescope, Alam
recorded data and observations of the planet using spectroscopy, the
study of electromagnetic radiation to help detect chemical elements. Alam specifically monitored WASP-62b as it swept in front of its host star
three times, making visible light observations, which can detect the
presence of sodium and potassium in a planet's atmosphere.

"I'll admit that at first I wasn't too excited about this planet,"
Alam says.

"But once I started to take a look at the data, I got excited." While
there was no evidence of potassium, sodium's presence was strikingly
clear. The team was able to view the full sodium absorption lines in their data, or its complete fingerprint. Clouds or haze in the atmosphere would obscure the complete signature of sodium, Alam explains, and astronomers usually can only make out small hints of its presence.

"This is smoking gun evidence that we are seeing a clear atmosphere,"
she says.

Cloud-free planets are exceedingly rare; astronomers estimate that less
than 7 percent of exoplanets have clear atmospheres, according to recent research. For example, the first and only other known exoplanet with a
clear atmosphere was discovered in 2018. Named WASP-96b, it is classified
as a hot Saturn.

Astronomers believe studying exoplanets with cloudless atmospheres can
lead to a better understanding of how they were formed. Their rarity
"suggests something else is going on or they formed in a different way
than most planets," Alam says. Clear atmospheres also make it easier to
study the chemical composition of planets, which can help identify what
a planet is made of.

With the launch of the James Webb Space Telescope later this year,
the team hopes to have new opportunities to study and better understand WASP-62b. The telescope's improved technologies, like higher resolution
and better precision, should help them probe the atmosphere even closer
to search for the presence of more elements, such as silicon.


========================================================================== Story Source: Materials provided by Harvard-Smithsonian_Center_for_Astrophysics. Note: Content may be edited
for style and length.


========================================================================== Related Multimedia:
* Artist_illustration_of_exoplanet_WASP-62b ========================================================================== Journal Reference:
1. Munazza K. Alam, Mercedes Lo'pez-Morales, Ryan J. MacDonald, Nikolay
Nikolov, James Kirk, Jayesh M. Goyal, David K. Sing, Hannah
R. Wakeford, Alexander D. Rathcke, Drake L. Deming, Jorge
Sanz-Forcada, Nikole K.

Lewis, Joanna K. Barstow, Thomas Mikal-Evans, Lars
A. Buchhave. Evidence of a Clear Atmosphere for WASP-62b:
The Only Known Transiting Gas Giant in the JWST Continuous
Viewing Zone. The Astrophysical Journal, 2021; 906 (2): L10 DOI:
10.3847/2041-8213/abd18e ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/01/210121185411.htm

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