by Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on exciting discoveries, scientific advances and more.
Astronomers have spotted what they believe is a rainbow-like phenomenon occurring on a planet outside our solar system for the first time, and it could reveal new insights into alien life.
WASP-76b, an ultra-hot exoplanet 637 light-years from Earth, was discovered by observations from the European Space Agency’s Cheops space telescope, or Characteristic ExOplanet Satellite, on WASP-76b.
Often seen on Earth, the effect consists of concentric, multicolored rings of light, and occurs when light reflects off clouds made of a uniform substance.
Outside of Earth, the halo effect was only visible on Venus until Cheops and other missions picked up an extremely faint signal suggesting that it is in the very hot atmosphere of WASP-76b. Based on the signal detected by Cheops, astronomers believe that the atmospheric phenomenon is directly opposite the Earth.
Researchers reported the details of the observation April 5 in the journal Astronomy & Astrophysics.
“There is no reason why glories haven’t been seen before outside our Solar System – it requires very specific conditions,” lead study author Olivier Demangeon, an astronomer at the Institute of Astrophysics and Space Sciences in Portugal, said in a statement. “First of all, you need atmospheric particles that are close to perfectly spherical, completely uniform and stable enough to see over a long period of time. The star of the nearby planet must be shining directly on it, and the observer – here Cheops – at the right orientation.”
A wild, scorching planet
WASP-76b has intrigued astronomers since its discovery in 2013.
The exoplanet orbits its host star closely, with intense heat and radiation received from that sun-like star – more than 4,000 times the amount of radiation Earth receives from our sun – caused WASP-76b to shrink, making it almost twice as large with Jupiter, the largest planet in our solar system.
The planet is tidally locked to its star, meaning that one side, known as day, always faces the star, while the other side of the planet is in perpetual night.
The day of WASP-76B reaches a scorching temperature of 4,352 degrees Fahrenheit (2,400 degrees Celsius). Elements that would normally form rocks on Earth melt and evaporate during the day before condensing and forming clouds that rain down molten iron at night.
Astronomers decided to target several observatories, including Cheops, the Hubble Space Telescope, the now retired Spitzer Space Telescope and NASA’s planet-hunting TESS mission, to study a light imbalance that apparently occurred while WASP-76b was in orbit. . in front of its host star.
Combined data from Cheops and TESS, or the Transiting Exoplanet Survey Satellite, suggested that the anomaly could be caused by something interesting happening in the atmosphere above the day.
Cheops captured data from WASP-76b as the planet passed in front of its star, making 23 observations over three years.
When the astronomers looked at the data, they noticed an unusual increase in the light coming from the eastern “terminus” of the planet, or the boundary light between the day and night sides. Meanwhile, less light was emitted from the western Terminator.
“This is the first time such a sharp change in the brightness of an exoplanet, its ‘phase curve,'” said Demangeon. “This discovery allows us to hypothesize that strong, localized and anisotropic (directly dependent) reflection may be the cause of this unexpected glow – the glow effect.”
Demangeon said he is delighted to be involved in the first detection of this type of light coming from an exoplanet.
“It was a special feeling – a special pleasure that doesn’t happen every day,” he said.
A colorful light on alien life
Glory and rainbows are not the same thing. A rainbow occurs when light is bent as it passes through two successive media of different densities, such as air to water. As the light is bent, it breaks into different colors, creating an arcing rainbow.
But the glory effect is created as light moves through a narrow opening and bends, creating colorful rings, patterns.
If astronomers are truly seeing the halo effect on WASP-76b, it means that the planet has persistent clouds made of remarkably spherical droplets—or clouds that are constantly replenishing. Either way, the presence of these clouds indicates that the planet’s atmosphere has a stable temperature.
The nature of what exactly is in the clouds on WASP-76b remains a mystery, but it could be iron, since the element has previously been found in the planet’s clouds.
“What’s important to keep in mind is the incredible scale of what we’re seeing,” Matthew Standing, a European Space Agency research fellow who studies exoplanets, said in a statement. Position was unrelated to the study.
“WASP-76b is hundreds of light-years away – a super-hot gas giant planet where it probably rains molten iron,” Standing said. “Despite the chaos, (researchers) seem to have detected signs of potential glory. It is an extremely weak signal.”
If astronomers are able to detect the faint signal of a halo-like phenomenon hundreds of light-years away, it may be possible to detect the presence of sunlight reflected off extraterrestrial bodies of water as well, according to the researchers.
“Further proof is needed to say definitively that this interesting ‘extra light’ is a rare glow,” Theresa Lueftinger, project scientist for the European Space Agency’s Ariel mission, said in a statement. She was not involved in the study.
Ariel, or the Major Exoplanet Survey Infrared Atmospheric Remote Sensing, is expected to launch in 2029 to study the atmospheres of a large and diverse selection of exoplanets.
Lueftinger said she believes the James Webb Space Telescope or Ariel could help prove the presence of the halo effect on WASP-76b.
“We could find brighter colors shining from other exoplanets,” she said.
For more CNN news and newsletters create an account at CNN.com
