Extreme exoplanet even more exotic than originally thought

Date:
October 5, 2021
Source:
Cornell University
Summary:
Considered an ultra-hot Jupiter -- a place where iron gets
vaporized, condenses on the night side and then falls from the
sky like rain -- the fiery, inferno-like WASP-76b exoplanet may
be even more sizzling than scientists had realized.



FULL STORY ========================================================================== Considered an ultra-hot Jupiter -- a place where iron gets vaporized,
condenses on the night side and then falls from the sky like rain --
the fiery, inferno- like WASP-76b exoplanet may be even more sizzling
than scientists had realized.


==========================================================================
An international team, led by scientists at Cornell University, University
of Toronto and Queen's University Belfast, reports the discovery of
ionized calcium on the planet -- suggesting an atmospheric temperature
higher than previously thought, or strong upper atmosphere winds.

The discovery was made in high-resolution spectra obtained with Gemini
North near the summit of Mauna Kea in Hawaii.

Hot Jupiters are named for their high temperatures, due to proximity to
their stars. WASP-76b, discovered in 2016, is about 640 light-years from
Earth, but so close to its F-type star, which is slightly hotter than
the sun, that the giant planet completes one orbit every 1.8 Earth days.

The research results are the first of a multiyear, Cornell-led project, Exoplanets with Gemini Spectroscopy survey, or ExoGemS, that explores
the diversity of planetary atmospheres.

"As we do remote sensing of dozens of exoplanets, spanning a range of
masses and temperatures, we will develop a more complete picture of the
true diversity of alien worlds -- from those hot enough to harbor iron
rain to others with more moderate climates, from those heftier than
Jupiter to others not much bigger than the Earth," said co-author Ray Jayawardhana, Harold Tanner Dean of the College of Arts and Sciences at
Cornell University and a professor of astronomy.

"It's remarkable that with today's telescopes and instruments, we
can already learn so much about the atmospheres -- their constituents,
physical properties, presence of clouds and even large-scale wind patterns
-- of planets that are orbiting stars hundreds of light-years away," Jayawardhana said.

The group spotted a rare trio of spectral lines in highly sensitive observations of the exoplanet WASP-76b's atmosphere, published in the Astrophysical Journal Letters on Sept. 28 and presented on Oct. 5 at the
annual meeting of the Division for Planetary Sciences of the American Astronomical Society.

"We're seeing so much calcium; it's a really strong feature," said
first author Emily Deibert, a University of Toronto doctoral student,
whose adviser is Jayawardhana.

"This spectral signature of ionized calcium could indicate that the
exoplanet has very strong upper atmosphere winds," Deibert said. "Or the atmospheric temperature on the exoplanet is much higher than we thought." Gemini North is part of the international Gemini Observatory, a program
of National Science Foundation's NOIRLab.

========================================================================== Story Source: Materials provided by Cornell_University. Original written
by Blaine Friedlander, courtesy of the Cornell Chronicle. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Emily K. Deibert, Ernst J. W. de Mooij, Ray Jayawardhana, Jake
D. Turner,
Andrew Ridden-Harper, Luca Fossati, Callie E. Hood, Jonathan
J. Fortney, Laura Flagg, Ryan MacDonald, Romain Allart, David
K. Sing. Detection of Ionized Calcium in the Atmosphere of the
Ultra-hot Jupiter WASP-76b. The Astrophysical Journal Letters,
2021; 919 (2): L15 DOI: 10.3847/2041-8213/ ac2513 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211005124652.htm

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