When a star reaches the end of its life, part of its mass can collapse onto its core. It ends up becoming so heavy that it can no longer resist its own gravity. He collapses, too. And the star explodes in that the astronomersastronomers called a supernova. Elements of all kinds are then dispersed in space. Elements which will later become so many new stars and planets.
NASA reveals spectacular videos of supernova explosions
But such a supernova explosion can also occur in a binary systembinary system. When a dwarf star sucks matter from its companion. It becomes more and more dense. Nuclear fusion reactions start and propagate so efficiently that the star goes supernova.
Dozens of supernovae in the early Universe
These are some of these extreme phenomena that the James Webb Space Telescope (JWST) has just revealed. Of the supernovaesupernovae in L’UniverseUniverse primitive. Among the most distant that astronomers know. And above all, ten times more numerous than what the researchers expected.
On the occasion of the 244e AAS meeting,American Astronomical Societyastronomers from the University of Arizona (USA) explained how they analyzed imaging data obtained as part of the JWST program Advanced Deep Extragalactic Survey (Jades). They compared several images taken a year apart in search of objects whose brightnessbrightness would have varied. And they found about 80 of them in an area of the sky the size of a grain of rice held at arm’s length.
Among the oldest known supernovae
Remember that before the launch of James Webb Space TelescopeJames Webb Space Telescopeonly a handful of supernovae had been discovered at an age of our Universe that could correspond to that of “young adult”. What astronomers call a redshiftredshift of the order of 2. When the Universe was only 3.3 billion years old. Thanks to JWST, they can now access supernovae in the“adolescenceadolescence » or even “pre-adolescence” of the universe. When the latter was no more than 2 billion years old. The oldest of all thus displays a redshift of 3.6. It came from a massive star that exploded when our Universe was no more than 1.8 billion years old!
But in their trap, the researchers also brought back some so-called type Ia supernovae. Supernovae are of particular interest to them because their luminosity is so predictable that astronomers use them to measure distances in the cosmos. To also assess to what speedspeed our Universe is expanding.
Theories validated and others to be shaken up?
Using the James-Webb Space Telescope, researchers have identified at least one Type Ia supernova with a redshift of 2.9. Understand that the explosion of the white dwarf behind it occurred when our Universe was only 2.3 billion years old. And the first analyzes seem to confirm that it does indeed have the same intrinsic luminosity as those closer that astronomers already knew. Enough to confirm, while awaiting further validations, that the distance and expansion rate measurements do not need to be revised.
James Webb telescope reveals ‘incredible details’ of recent supernova in Milky Way
What researchers also hope, by studying all these ancient supernovae, is to be able to better understand the mechanisms of formation and end of life of stars. “The James Webb Space Telescope is so sensitive that almost everywhere it looks it finds supernovae. It’s a short story windowwindowwhich opens onto our Universe. And every time we’ve done this in the past, we’ve discovered extremely exciting things, things we didn’t expect.”conclude the astronomers in a NASA press release.
