James Webb has identified in the “Galactic neighborhood” the Esopianeta TWA 7B: it is the smallest and most cold ever captured directly by a space telescope.
The James Webb spatial telescope has marked a new stage in his career: for the first time he identified an exoplane through Direct imagean extremely rare and complex technique. This was announced by a team of international researchers, including the Astrophysics Anne-Marie Lagrances of the Paris Observatory, in a study published in the magazine Nature.
The protagonist of the discovery is Two 7b, A planet located about 100 light years from the earthin the constellation of the Idra, in a cosmic region that scientists define the “galactic neighborhood“. Its mass is similar to that of Saturn, but unlike the giants giants already photographed in the past, Two 7b is considerably lighter: according to the authors of the study, it is The smallest and colder planet ever captured directly by a space telescope.
Technological turning point. Since its launch in 2021 and the entry into operation in 2022, James Webb has revolutionized our vision of the universe, offering images never seen in primordial galaxies and planetary atmospheres. However, so far his gaze had concentrated above all on exoplanets already knownanalyzing its chemical composition through spectroscopy.
With Two 7b, Webb took a step forward: has identified a new planet using his infrared vision directlymade possible thanks to a crucial tool, the coronographer integrated into the Miri module (Mid-Infrared Instrument). This device blocks the dazzling light of the mother star, Twa, simulating an eclipse and thus allowing “seeing weak and hidden objects like a planet.
A stellar system in formation. Twa 7 is one very young star – Just 6.4 million years, compared to the 4.5 billion of our sun – surrounded by a large album of gas and dust, the raw material for the formation of planets. Its stellar system is particularly interesting because it is almost frontally observable from the earth, offering a privileged view of the dust rings that make it up. It is precisely within one of these rings, in an apparently empty region, that Webb has identified a suspicion bright point. The analyzes excluded that it was a background galaxy or an object of our sun system. The characteristics of the source – position, brightness and infrared spectrum – unequivocally indicate that It is a planet.
A new era for direct observation. «Webb has multiplied our ability to detect planets through direct image for ten. So far this technique was limited to very hot and massive giants. Now we can start looking even smaller and smaller celestial bodies, “commented Lagrange.
The great challenge of direct observation is The weakness of the light of the planets compared to that of their mothers stars. It’s like trying to see a Lucciola next to a lighthouse. But Webb, with his sensitive tools and the ability to operate in the infrared, is showing that he can overcome this obstacle.
The dream: find a “second land”. The discovery of Twa 7b opens important prospects for the search for planets similar to the earth. Even if Twa 7b is still a gaseous giant, it is much closer to the parameters of the rocky planets than the giants such as Jupiter or Neptune.
“Our end goal remains the discovery of small, rocky and possibly habitable planets,” explained Lagrange. “But to get there, we must first understand how the different types of planets are formed and how planetary systems are structured”.
