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Astronomers have discovered for the first time what they believe to be a rainbow-like phenomenon on a planet outside our solar system, potentially providing new insights into alien worlds.
Observations from the European Space Agency's Cheops Space Telescope, or Characterizing ExOplanet Satellite, have detected a “glory effect” on WASP-76b, an ultra-hot exoplanet 637 light-years from Earth.
The effects commonly seen on Earth are: Concentric rings of colorful light that occur when light reflects off a cloud of uniform material.
Outside of Earth, the Glory effect was only seen on Venus, until Cheops and other missions received an incredibly faint signal suggesting it occurred in the hellishly hot atmosphere of WASP-76b. I did. Based on the signals detected by Khufus, astronomers believe that the atmospheric phenomenon is directly facing the Earth.
The researchers reported details of their observations on April 5 in the journal Astronomy & Astrophysics.
“There's a reason why we haven't seen any glory outside our solar system before. It requires very specific conditions,” said lead author of the study, from the Portuguese Institute of Astrophysics and Space Sciences. Astronomer Olivier Demangeon said in a statement. “First, we need atmospheric particles that are nearly perfectly spherical, perfectly homogeneous, and stable enough to be observed over long periods of time. Stars near the planet can be observed directly by an observer (here Khufus) in the correct orientation. We need to shine a light on it.”
WASP-76b has intrigued astronomers since its discovery in 2013.
Exoplanets orbit close to their host stars and are exposed to intense heat and radiation. The radiation it received from its Sun-like star (more than 4,000 times the amount of radiation Earth receives from the Sun) caused WASP-76b to swell to almost twice the size of Jupiter, the largest planet in our solar system.
C. Wilson/P. Raven/ESA
A simulated view shows Venus (left) and its possible glory on Earth.
The planet is tidally locked to the star, with one side, known as the dayside, always facing the star, and the other side of the planet permanently at night.
During the day, WASP-76B reaches scorching temperatures of 4,352 degrees Fahrenheit (2,400 degrees Celsius). Typically, the elements that form rocks on Earth melt and evaporate on the day side, then condense to form clouds and release rain of molten iron on the night side.
Astronomers focused on a number of observatories, including the Cheops Space Telescope, the Hubble Space Telescope, the now-retired Spitzer Space Telescope, and NASA's planet-hunting mission TESS to study what they believe to be a light imbalance. I decided to do it. It happened while WASP-76b was orbiting in front of its host star.
Combining data from Cheops and TESS (Transiting Exoplanet Survey Satellite) suggests that this anomaly may be due to something interesting happening in the atmosphere above the dayside. .
Kufps acquired data from WASP-76b as the planet passed in front of its star, making 23 observations over three years.
When astronomers examined the data, they noticed an unusual increase in light from Earth's eastern “terminator,” the light that separates day and night. Meanwhile, less light is emitted from the western terminator.
“This is the first time that such a sudden change in the brightness of an exoplanet, its 'phase curve', has been detected,” DeMansion said. “This discovery gives rise to the hypothesis that this unexpected glow may be caused by a strong, locally anisotropic (direction-dependent) reflection, or glow effect.”
Demangeon said he was excited to be involved in the first detection of this kind of light coming from an exoplanet.
“It was a very special feeling. It was a special satisfaction that you don't get every day,” he said.
Glory and rainbows are not the same thing. Rainbows occur when light bends as it passes successively through two media of different densities, such as air to water. As the light bends, it changes colors, creating an arcing rainbow.
But the glory effect is created when light passes through a narrow aperture and bends, creating a ring of colorful patterns.
If astronomers are indeed observing WASP-76b's glory effect, it means that the planet has a persistent cloud of perfectly spherical droplets, a cloud that is constantly replenished. Masu. In any case, the presence of such clouds suggests that the temperature of the planet's atmosphere is stable.
What exactly is inside WASP-76b's cloud remains a mystery, but this element has been previously detected in clouds on Earth, so it could be iron.
M. Kohnmesser/ESO
The artist's illustration shows a night view of exoplanet WASP-76b, with steel raining from the sky.
“The important thing to keep in mind is the incredible scale of what we are witnessing,” Matthew Standing, a researcher at the European Space Agency who studies exoplanets, said in a statement. Stated. Standing was not involved in the study.
“WASP-76b is a very hot gas giant planet hundreds of light years away that is likely to be rained down with molten iron,” Standing said. “Despite the confusion,[the researchers]seem to have detected a potential sign of glory. It's an incredibly weak signal.”
Researchers say that if astronomers can observe faint signals of phenomena such as Glory from hundreds of light-years away, they could one day detect the presence of sunlight reflecting off bodies of water on other planets. It may become.
“More evidence is needed to say conclusively that this interesting 'extra light' is a rare glory,” Theresa Luftinger, project scientist for the European Space Agency's Ariel mission, said in a statement. She was not involved in the study.
Ariel (Atmospheric Remote Sensing Infrared Exoplanet Massive Survey) is scheduled to launch in 2029 to study the atmospheres of large and diverse exoplanets.
Luftinger said he believes the James Webb Space Telescope and Ariel may be able to prove the existence of WASP-76b's glory effect.
“We may also discover brighter colors shining from other exoplanets,” she says.
