After a first photograph published the day before, NASA revealed on Tuesday all of the first images of the most powerful space telescope ever designed, James Webb, shots marking the start of its scientific operations, awaited for years by astronomers around the world.
• Read also: The first image of the James Webb telescope reveals the very young Universe
On the program of a live one hour during which the images were revealed one by one: two nebulae illustrating the life cycle of stars, an exoplanet and a compact group of galaxies.
"Each image is a new discovery," said NASA boss Bill Nelson. “Each will give humanity a view of the Universe that we have never seen before.”
On Monday, a first image taken by the telescope, illustrating the distant times of the cosmos, was unveiled, in the presence of US President Joe Biden, who hailed a "historic" moment.
The shot, which is teeming with detail, shows galaxies formed shortly after the big bang, more than 13 billion years ago.
One of the main missions of James Webb, a jewel of engineering worth 10 billion dollars and the most powerful space telescope ever designed, is indeed the exploration of the very young Universe. This first demonstration was intended to give an overview of its capabilities in this area.
But it was only one of the five targets announced by NASA for this real surprise bag, which officially marks the start of scientific observations of the telescope, and whose content had until now been carefully kept secret in order to raise suspense.
Among them: the images of two nebulae, very photogenic and gigantic clouds of gas and dust.
The Carina Nebula, located about 7600 light-years away, illustrates star formation. It is home to many that are massive, several times the size of our Sun.
The Southern Ring Nebula is a so-called planetary nebula (although it has nothing to do with planets): it is a huge cloud of gas surrounding a dying star.
Another target: Stephan's Quintet, a group of interacting galaxies.
The last cosmic object whose observation was revealed on Tuesday is an exoplanet, that is to say a planet in orbit around a star other than our Sun, one of the main lines of research of James Webb.
It was not actually photographed, rather it was analyzed using spectroscopy, a technique used to determine the chemical composition of a distant object. In this case WASP-96 b, a giant planet composed mainly of gas.
By combining the data obtained previously thanks to other telescopes and those of James Webb, "we will probably be able to detect water vapor" in its atmosphere, estimated with AFP José A. Caballero, astronomer at the Centro de Astrobiologia in Spain and specialist in exoplanets.
These data "will be interesting for me, to see the capabilities of the telescope and the instruments", he added, even if he considers this first exoplanet a bit "boring", and looks forward to smaller and less hot exoplanets are observed.
James Webb had been launched into space about six months ago, on Christmas Day, from French Guiana by an Ariane 5 rocket. The result of a huge international collaboration, and in the works since the 1990s, it is stationed 1.5 million kilometers from Earth.
The publication of these first images marks the beginning of an immense scientific adventure, which must extend over many years and transform our understanding of the Universe.
Researchers around the world have reserved observation time with James Webb, whose program – for its first year of operation – has already been carefully determined by a committee of specialists, and made public.
The telescope has enough fuel to operate for 20 years. Some 20,000 people worked on this project around the world, in a huge international collaboration.