Scientists detect the brightest exoplanets outside the solar system

Scientists have detected the brightest exoplanets ever observed outside the solar system, according to a study published on Monday revealing a blazing world where clouds of titanium raindrops fall.

This strange outer planet, located over 260 light-years away from Earth, reflects 80% of the light from its host star, according to new observations from the European space telescope "CHEOPS."

This is the first exoplanet outside the solar system to rival the brightness of Venus, the brightest object in our night sky after the Moon.

This discovered outer planet, named LTT9779b, which is the size of Neptune, orbits its star in just 19 hours.

Due to its close proximity, the illuminated side of LTT9779b reaches a temperature of 2000 degrees, which is considered extremely hot and does not allow for cloud formation. However, the reflection from LTT9779b indicates the presence of clouds.

"This posed a real puzzle," said Vivien Parmentier, a researcher at the Cote d'Azur Observatory and a participant in the study published in the journal "Astronomy and Astrophysics." Then "the researchers looked into how these clouds form in the same way condensation occurs in the bathroom after a hot shower," the researcher explained in a statement.

Just as hot water in the bathroom causes steam and condensation due to the flow of hot metal and silicates - the material from which glass is made - an excess saturation occurred in the atmosphere of the LTT9779b planet, leading to the formation of mineral clouds.

Shield -

 

But the planet hides other surprises. In the past, the only known outer planets to rotate around their star at a fast pace (in less than 24 hours) were either gas giants ten times the size of Earth or rocky planets the size of half of Earth.
The size of the outer planet LTT9779b is about five times that of Earth and is located in an area astronomers call the "hot Neptune desert," where planets of this size are not expected to exist, according to Parmentier.

Meanwhile, astronomers expected that a planet like LTT9779b would have its atmosphere evaporate due to the close proximity of its star, leaving behind barren rocks.

They found an explanation for this, which lies in the fact that "the mineral clouds of LTT9779b act as a mirror," as they reflect light and prevent the atmosphere from evaporating, according to Maximilian Guenther, the lead scientist in the "CHEOPS" project at the European Space Agency.

Guenther told Agence France-Presse that the clouds act as a "shield," similar to the shields that protect "spacecraft in the ancient rings of the Star Trek series."

The researcher pointed out that this represents an "important step" in demonstrating how a Neptune-sized planet can survive in a similar environment.

The "CHEOPS" space telescope, belonging to the European Space Agency, was sent in 2019 to characterize planets discovered outside our solar system. The telescope measured the reflective ability of LTT9779b by comparing the light before and after the planet disappeared outside the solar system behind its star.

 

AFP