Discovery of Rainbow-like Phenomenon on Scorching Exoplanet Marks a Scientific Breakthrough
Scientists have identified a rainbow-like phenomenon, referred to as the 'glory effect', on an exoplanet located beyond our solar system. This groundbreaking observation signifies a remarkable advancement in astronomical research.
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A rainbow-like phenomenon has been observed by astronomers on a planet outside our solar system for the first time. This discovery could provide valuable insights into alien worlds.
The Cheops space telescope from the European Space Agency discovered a special phenomenon on WASP-76b, an ultra-hot exoplanet located 637 light-years away from us.
This phenomenon, known as the "glory effect," is characterized by concentric and colorful rings of light. It happens when light bounces off clouds that are made of the same material.
Beyond Earth, the glory effect was previously observed only on Venus. However, recent missions like Cheops have detected a very faint signal hinting that this phenomenon also happens in the atmosphere of the scorching hot WASP-76b. Astronomers have reason to believe that this atmospheric spectacle is directly visible from Earth.
This is an artist's concept of the exoplanet GJ 9827d, the smallest exoplanet where water vapor has been detected in the atmosphere. The planet could be an example of potential planets with water-rich atmospheres elsewhere in our galaxy. With only about twice Earth's diameter, the planet orbits the red dwarf star GJ 9827. Two inner planets in the system are on the left. The background stars are plotted as they would be seen to the unaided eye looking back toward our Sun. The Sun is too faint to be seen. The blue star at upper right is Regulus; the yellow star at center bottom is Denebola; and the blue star at bottom right is Spica. The constellation Leo is on the left, and Virgo is on the right. Both constellations are distorted from our Earth-bound view from 97 light-years away.
This artist's illustration shows the exoplanet GJ 9827d, which is the smallest exoplanet where water vapor has been found in the atmosphere. Scientists believe this planet could be one of many in our galaxy with water-rich atmospheres. It is just about twice the size of Earth and orbits a red dwarf star named GJ 9827. There are two other planets closer to the star in this solar system.
In the background of the illustration, you can see stars as they would appear to the naked eye from our perspective looking back towards the Sun. The Sun is too dim to be visible in this image. Regulus, a blue star, is at the top right, while Denebola, a yellow star, is in the center bottom, and Spica, another blue star, is at the bottom right. On the left side, you can see the constellation Leo, and on the right, the constellation Virgo. Keep in mind that the appearance of these constellations is slightly altered due to our distance of 97 light-years from Earth.
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Researchers shared their findings in the journal Astronomy & Astrophysics on April 5. Lead study author Olivier Demangeon, an astronomer at the Institute of Astrophysics and Space Sciences in Portugal, explained that the phenomenon of no glory outside our Solar System is due to the specific conditions required. The atmospheric particles must be perfectly spherical, uniform, and stable for a long time. Additionally, the planet's star needs to shine directly at it, with the observer, in this case Cheops, at the right orientation.
A wild, scorching planet
WASP-76b has intrigued astronomers ever since its discovery in 2013.
The exoplanet, known as WASP-76b, orbits very close to its host star. The intense heat and radiation it receives from this sun-like star, which is over 4,000 times more than what Earth gets from our sun, has caused WASP-76b to expand in size. In fact, it is almost double the size of Jupiter, the largest planet in our solar system.
A simulated view shows a glory as it may appear on Venus (left) and Earth.
A simulated view shows a glory as it may appear on Venus (left) and Earth.
C. Wilson/P. Laven/ESA
The planet WASP-76B is tidally locked to its star, with one side always facing the star (dayside) and the other side in permanent darkness.
On the dayside of WASP-76B, temperatures soar to a scorching 4,352 degrees Fahrenheit (2,400 degrees Celsius). The extreme heat causes elements that would normally form rocks on Earth to melt and evaporate before condensing into clouds. These clouds release molten iron rain on the night side of the planet.
Astronomers teamed up multiple observatories, such as Cheops, the Hubble Space Telescope, the retired Spitzer Space Telescope, and NASA’s TESS mission, to investigate an unusual light pattern observed during the orbit of WASP-76b in front of its host star.
Data from Cheops and TESS suggested that the strange light imbalance could be linked to a fascinating phenomenon happening in the atmosphere above the planet's dayside.
Penn State
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Cheops collected information on WASP-76b as it crossed in front of its star, conducting 23 observations over a span of three years.
Upon analyzing the data, scientists observed a peculiar rise in brightness from the eastern edge of the planet, known as the terminator, where day transitions into night. In contrast, there was a decrease in brightness from the western terminator.
Demangeon shared that this is the first instance where a significant shift in brightness, known as the 'phase curve', has been observed on an exoplanet. He suggested that this unusual luminosity may be the result of a distinct, concentrated, and directionally dependent reflection known as the glory effect.
He expressed his excitement at being part of the team that made the groundbreaking discovery of this unique light emission from an exoplanet.
“It was such a special feeling — a particular satisfaction that doesn’t happen every day,” he said.
Colorful light on alien worlds
Rainbows and glory are different phenomena. Rainbows form when light passes through different densities, like from air to water, and bends, splitting into colors to create a rainbow arc.
On the other hand, the glory effect is produced when light passes through a narrow opening, bending and forming colorful, patterned rings.
Astronomers may be observing the glory effect on WASP-76b, indicating that the planet has clouds that are either constantly replenishing or made of perfectly spherical droplets. This suggests that the planet's atmosphere maintains a stable temperature.
The composition of the clouds on WASP-76b is still unknown, but it is possible that they contain iron, as this element has been found in clouds on the planet before.
An artist's illustration shows the night-side view of the exoplanet WASP-76b, where iron rains down from the sky.
An artist's illustration shows the night-side view of the exoplanet WASP-76b, where iron rains down from the sky.
Matthew Standing, a European Space Agency research fellow who studies exoplanets, emphasized the immense scale of what we are observing. He was not part of the study.
Standing mentioned that WASP-76b is located several hundred light-years away and is a hot gas giant planet where it likely rains molten iron. Even amidst the chaos, researchers have managed to detect a faint signal that could indicate the presence of a glory.
The researchers believe that if astronomers can observe such a faint signal from hundreds of light-years away, they may also be able to detect sunlight reflecting off extraterrestrial bodies of water in the future.
Theresa Lueftinger, a project scientist for the European Space Agency's Ariel mission, mentioned that more evidence is required to confirm if the unique 'extra light' is a rare phenomenon. She clarified that she was not part of the study.
Ariel, also known as the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, is scheduled to be launched in 2029. The mission aims to analyze the atmospheres of a wide variety of exoplanets.
Lueftinger thinks that either the James Webb Space Telescope or Ariel could potentially provide evidence of the glory effect on WASP-76b.
She also mentioned the possibility of discovering more stunningly colorful exoplanets in the future.
Editor's P/S:
The discovery of the glory effect on WASP-76b is a testament to the remarkable capabilities of modern astronomical instruments like the Cheops space telescope. This finding opens up exciting possibilities for studying alien atmospheres and uncovering the mysteries of exoplanets beyond our solar system. The ability to detect such faint signals from distant planets suggests that astronomers may soon be capable of detecting signs of life, such as the reflection of sunlight from oceans or lakes, on other worlds.
The glory effect on WASP-76b also provides valuable insights into the planet's atmospheric dynamics and composition. The presence of stable, spherical cloud particles suggests that the planet's atmosphere is relatively stable and well-mixed, despite the extreme heat and radiation it receives from its host star. Further observations of WASP-76b and other exoplanets will help astronomers better understand the diversity of atmospheric conditions in our galaxy and beyond.
