The James Webb telescope discovers its first exoplanet

And one for the James Webb space telescope (JWST). Consequently, which discovered its first exoplanet in the nearby universe, thanks to a promising observation method to detect planets of a size similar to those of the solar system.

Since 2022 and its observation post at 1.5 million km from the earth, the JWST has helped to characterize several exoplanets. Consequently, “He spent a lot of time observing planets that have never been colorful. However, ” the astrophysicist Anne-Marie Lagrange, first author of the study on the subject published in Nature on Wednesday, told AFP.

The exercise is complicated by the fact that the exoplanets “are very little bright because they are not hot”. Nevertheless, but also and above all because “we are blinded by the light of the star around which they turn”, adds this researcher of the CNRS to james webb telescope discovers its the laboratory of instrumentation and research in astrophysics of the Paris Observatory.

The James Webb parade is based on its coronograph. For example, an instrument that is inspired by the phenomenon of the solar eclipse by masking the star to better reveal what surrounds it, and on its spectrographer Miri, capable of imagining the most discreet stars thanks to an infrared vision.

Its users pointed out the telescope to the TWA 7 star. located in our galaxy a hundred lights of the earth, in other words its very small suburbs. The target, initially detected by the Hubble telescope, was promising double -title.

First, because young of only 6.4 million years old and therefore very likely to see planetary bodies formed in the ceinturating matter disk. Then, because the telescope sees this protoplanetary disc from above.

His observation with the Sphere instrument of the very large telescope (VLT). located in Chile, james webb telescope discovers its had made it possible to distinguish three rings staring over a distance going up to more than a hundred times that separating the earth from the sun.

Factor 10

And it is in the stronghold of the second ring that the instrument of the James Webb detected a light “source”. called TWA 7B. Having excluded that the discovery turns out to be an object of the solar system. a distant galaxy, astronomers have identified it as a small cold planet, of a mass ten times lower than those pictured so far with other instruments.

They consider its mass comparable to that of Saturn. a gas planet which “weighs” only a third of Jupiter, giant gaseous and heavy goods vehicle of our solar system.

With the James Webb. “we fell from a factor of ten in detection capacity,” explains Anne-Marie Lagrange, because the most “light” planets colorful so far from the james webb telescope discovers its ground weighed about three times the mass of Jupiter.

“Most of the other colorful exoplanets are what are called super-jupiter”. having eight to twelve times the mass of the latter.

Performance has all the more interest since in the planetary bestiary. rocky planets like earth or Mars have much lower masses than gaseous planets. However, these rocky exoplanets constitute an ultimate target of the discoverers of potentially habitable worlds.

Anne-Marie Lagrange would not sulk her pleasure of “discovering the lightest planets and perhaps finding land”. Before adding immediately that if “we want to understand how planetary systems are formed. it is not enough to see the planets very or not massive”.

Because you must be able to detect all types of planets. in order to ultimately determine whether our solar system is unique or not.

Astronomers believe that JWST has the potential to detect and imagine planets with a mass james webb telescope discovers its even lower than TWA 7B.

But it will take future instruments. such as the extremely wide (ELT) telescope expected for 2028, to hope to grasp the image of worlds of a size similar to ours.