A team of European scientists say they have discovered why a dazzling exoplanet is so ridiculously bright. According to their recently published PaperIt has little to do with the extremely metallic – literally and figuratively – titanium clouds of the “ultra-hot” planet.
The exoplanet, called LTT9779 b, orbits a star 260 light-years from Earth and boasts the highest albedo — basically, the fraction of light reflected back into space — of any planet ever discovered in our galaxy. For context, Earth’s albedo sits at about 30 percent, while Venus, the highest planet in our solar system, sits at 75 percent. The albedo of LTT9779 b also tops 80.
So, in other words, it’s very bright — an observation that baffles scientists given the size of the world and its proximity to the star. It is about the size of the medium-sized planet Neptune, and as it completes a full orbit every 19 hours, it is very close to its home star. Usually, like Ars Technica notesOnly very small, rocky, or very large gassy planets appear very close to their stars.
It’s pretty close, in fact, according to that Ars Its surface temperature sits somewhere around 2,000 degrees Celsius. At that temperature and proximity, scientists wouldn’t normally expect a planet to have much of an atmosphere, let alone one as bright as this one.
“It’s a planet that shouldn’t exist,” said Vivienne Parmentier, a researcher at the Côte d’Azur Observatory and co-author of the study, published in the journal Last Week. Astronomy and astronomyA said statement. “We expect planets like this to have their atmosphere blown away by their star, leaving behind a bare rock.”
To explain the planet’s brightness, the researchers looked at data from the European Space Agency’s Characteristic Exoplanet Satellite (CHEEOPS), a second-generation exoplanet tracking satellite. CHEOPS tracked the planet as it moved behind its home star — also known as a secondary eclipse — ten different times, allowing scientists to more accurately measure the planet’s brightness.
Taking those observations, they were able to develop a theory that explained the planet’s glow: clouds of glass and metal, acting as a protective planetary mirror.
“Clouds reflect light and prevent the planet from overheating and evaporating,” study lead author Sergio Hoyer, a researcher at the Marseille Astrophysics Laboratory, said in a statement. “Meanwhile, high metallicity makes the planet and its atmosphere heavier, making it harder to fly.”
“It was really a puzzle until we realized that we had to think of this cloud formation like condensation in the bathroom after a hot shower,” Parmentier said. “To make steam in a bathroom, you can either cool the air until the water vapor condenses, or continue running hot water until clouds form because the air is so saturated with steam that it can’t hold any more.”
“Also,” LTT9779 b is so hot that it can form metal clouds because its atmosphere is saturated with silicate and metal vapors.
In other words, because LTT9779 b’s atmosphere is so overloaded with glass silicates and metals, those particles are trapped in a hellish, titanium-laced version of Earth’s water cycle that continuously condenses and rains down on the horrendously hot planet.
“Imagine a world burning close to its star, with thick clouds of metal falling from titanium droplets,” James Jenkins, an astronomer at the University of Diego Portales in Santiago, Chile, said in a statement.
The James Webb Space Telescope hopes to soon focus its powerful eye on LTT9779 b so scientists can learn more about this strange world. At the same time, we do not recommend building a summer house there, taking into account the titanium precipitation and the surface temperature of 2,000 degrees Celsius.
More about exoplanets: James Webb Telescope Discovers Mysterious Water Vapor Surrounding Alien Planet