‘Like a mirror’: Astronomers identify most reflective exoplanet

A scorching sizzling world the place steel clouds rain drops of titanium is essentially the most reflective planet ever noticed outdoors of our Photo voltaic System, astronomers mentioned on Monday.

This unusual world, which is greater than 260 light years from Earth, displays 80 p.c of the sunshine from its host star, in keeping with new observations from Europe’s exoplanet-probing Cheops space telescope.

That makes it the primary exoplanet comparably shiny as Venus, which is the brightest object in our night time sky apart from the Moon.

First found in 2020, the Neptune-sized planet referred to as LTT9779b orbits its star in simply 19 hours.

As a result of it’s so shut, the aspect of the planet going through its star is a scorching 2,000 levels Celsius, which is taken into account far too sizzling for clouds to kind.

But LTT9779b appears to have them.

“It was actually a puzzle,” mentioned Vivien Parmentier, a researcher at France’s Cote d’Azur Observatory and co-author of a brand new research within the journal Astronomy and Astrophysics.

The researchers then “realized we must always take into consideration this cloud formation in the identical means as condensation forming in a toilet after a sizzling bathe,” he mentioned in an announcement.

Like working hot water steams up a toilet, a scorching stream of steel and silicate—the stuff of which glass is made—oversaturated LTT9779b’s environment till metallic clouds fashioned, he mentioned.

Surviving ‘Neptune desert’

The planet, which is round 5 instances the scale of Earth, is an outlier in different methods.

The one exoplanets beforehand discovered that orbit their stars in lower than 24 hours are both fuel giants 10 instances larger than Earth—or rocky planets half its measurement.

However LTT9779b lives in a area referred to as the “Neptune desert”, the place planets its measurement usually are not alleged to be discovered.

“It is a planet that should not exist,” Parmentier mentioned.

“We anticipate planets like this to have their environment blown away by their star, forsaking naked rock.”

The planet’s metallic clouds “act like a mirror,” reflecting away gentle and stopping the environment from being blown away, in keeping with the European House Company’s Cheops undertaking scientist Maximilian Guenther.

“It is a bit like a defend, like in these previous Star Trek movies the place they’ve shields round their ships,” he informed AFP.

The analysis marks “an enormous milestone” as a result of it reveals how a Neptune-sized planet may survive within the Neptune desert, he added.

The European House Company’s Cheops space telescope was launched into Earth’s orbit in 2019 on a mission to research planets found outdoors our Photo voltaic System.

It measured the reflectiveness of LTT9779b by evaluating the sunshine earlier than and after the exoplanet disappeared behind its star.

© 2023 AFP