About the episode
Astronomers have studied the rocky exoplanet GJ486b using the James Webb telescope. The planet, which is about 30 percent larger than Earth, is too close to its star to be habitable. With surface temperatures of around 430 degrees, it is just a little too hot for us.
And yet, researchers near the planet have detected traces of water vapor. If that water vapor is coming from the planet, it would suggest that the planet has an atmosphere, despite those gigantic temperatures.
Water vapor has previously been found in the vicinity of gassy exoplanets, but until now no atmosphere has ever been found around a rocky exoplanet. It is true, the researchers immediately add, that the water vapor can also come from the star and not the planet.
More observations are needed, with other instruments on board the telescope, to know for sure where the water vapor is coming from. If there really is an atmosphere, it would probably need to be constantly fed with steam from the planet’s interior.
The planet also has a fixed day side and a fixed night side. That day side will be studied, among other things, in a subsequent study. How warm the warmest point is there and where that is relative to the star can say something about how a possible atmosphere circulates heat, among other things.
Read more about the discovery here: Webb Finds Water Vapor, But From a Rocky Planet or Its Star?
2023-05-03 19:01:40
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