.jpg)
LTT9779b reflects up to 80% of the light from its host star. Photo: ESA.
This peculiar exoplanet is located more than 260 light-years away from Earth, reflecting up to 80% of the light from its host star, according to recent observations from the European space telescope Cheops.
The exceptional light reflection makes it the first exoplanet to exhibit brightness similar to Venus, the brightest celestial body in the night sky as seen from Earth.
First detected in 2020, this exoplanet is named LTT9779b, and it is roughly the size of Neptune, orbiting its star in just 19 hours.
LTT9779b and its host star are very close together, resulting in a scorching surface temperature of about 2,000 degrees Celsius, deemed too hot for clouds to form.
After conducting research, astronomers concluded that cloud formation on this planet operates similarly to the condensation of water vapor.
Similar to the way hot steam rises in a bathroom, a stream of hot metal and silicate saturated the atmosphere of LTT9779b until metal-filled clouds formed. Clearly, this planet is full of mysteries and exceptions.
Previously discovered exoplanets orbited their stars with orbits of less than 24 hours. They were either gas giants, ten times larger than Earth, or rocky planets about half the size of Earth.
In contrast, LTT9779b exists in a region known as the “Venus desert,” where planets of its size cannot be found.
“It is a planet that should not exist. The atmospheres of such planets would be blown away by their stars, leaving barren rocks,” said researcher Vivien Parmentier at the Côte d’Azur Observatory in France.
The European Space Agency’s Cheops space telescope was launched into Earth’s orbit in 2019 with a mission to explore exoplanets beyond our Solar System. It measures the light reflection of LTT9779b by comparing the star’s brightness before and after the exoplanet passes in front of its host star.