The James Webb (JWST) space telescope 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 1.5 million km from the earth, the JWST has helped characterize several exoplanets. “It spent a lot of time observing planets that have never been pictorial,” said Astrophysics Anne-Marie Lagrange, the first author of the study on the subject published in Nature on Wednesday.
The exercise is complicated because the exoplanets “are very little bright because they are not heat”, but also and especially because “we are blinded by the light of the star that turn,” adds this CNR researcher to the instrumentation and astrophysic research laboratory of the Paris Observatory.
A planet of only 6.4 million years
The James Webb parade is based on its coronographer, an instrument inspired by the phenomenon of the solar eclipse masking the star to better reveal what surrounds it, and in its Miri spectrograph, capable of imagining the most discreet stars thanks to an infrared vision.
Its users pointed out the telescope to the star Twa 7, located in our galaxy, one hundred lights of the earth, in other words, its very small suburbs. The objective, initially detected by the Hubble telescope, promised the double Titus.
First, because only 6.4 million years old and, therefore, it is very likely that the planetary bodies formed on the disc of the Ceinturo matter are very likely. Then, because the telescope sees this protoplanetary disk from above.
His observation with the instrument of the very large telescope sphere (VLT), located in Chile, had allowed to distinguish three rings that looked at a distance more than a hundred times that separate the earth from the sun.
And it is in the strength of the second ring that the instrument of James Webb detected a light “source”, called TWA 7B. Having excluded that the discovery turns out to be an object of the solar system or a distant galaxy, astronomers have identified it as a small cold planet, of a mass ten times lower than those shown so far with other instruments.
“We fell from a ten -capacity factor for detection”
They consider its mass comparable to that of Saturn, a brilliant planet that “weighs” only a third of Jupiter, giant giants and vehicles of heavy goods of our solar system.
With the James Webb, “we fall from a ten ten-capacity factor,” explains Anne-Marie Lagrange, because the most “light” planets that are so far from the ground weighed about three times Jupiter’s mass.
“The majority of the other pictorial exoplanets are those called super-juupiter”, with eight times the mass of the latter.
The performance has more interest from the planetary bestiary, the rocky planets such as the Earth or Mars have much lower masses than the gaseous planets. However, these rock exoplanets constitute a final objective of the discoverers of potentially habitable worlds.
Anne-Marie Lagrange would not mistreat her pleasure to “discover the lighter planets and maybe find 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 it must be able to detect all types of planets, to ultimately determine whether our solar system is unique or not.
Astronomers believe that JWST has the potential to detect and imagine planets with an even lower dough than TWA 7B.
But future instruments will be needed, such as the extremely broad telescope (elt) expected by 2028, to hope to understand the image of worlds of a size similar to ours.
Source: BFM TV
