The angle of the sky to which astronomers are aiming the James Webb Space Telescope this time is no larger than a grain of rice. However, they found dozens of ancient supernovae there. The promise of great discoveries is enough.
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. It also collapses. And the star explodes in it Astronomy scientistsAstronomy scientists It's called a supernova. Elements of all kinds are then dispersed in space. Elements that would later become many new stars and planets.
But such a supernova explosion could also occur in… Binary systemBinary system. When a dwarf star absorbs matter from its companion. It becomes more and more intense. Nuclear fusion reactions begin and spread so efficiently that the star goes supernova.
Dozens of supernovae in the early universe
These are some of these extreme phenomena that have just been revealed by the James Webb Space Telescope (JWST). Subordinate SupernovaeSupernovae in'beingbeing Primitive. It is the furthest thing astronomers know. More importantly, the number is ten times greater than the researchers expected.
On the occasion of the 244th anniversaryH 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 Extragalactic Deep Survey (jade). They compared several photos taken a year apart, looking for things that… brightnessbrightness May vary. 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 launching James Webb Space TelescopeJames Webb Space TelescopeOnly a few supernovae have been discovered at the age of our universe that can be consistent with the age of the universe “young adult”. What astronomers call a RedshiftRedshift Of the order of 2. When the universe was only 3.3 billion years old. Thanks to the James Webb Space Telescope, they can now access supernovae in space“TeenTeen » or even “pre-adolescent” Universe. When the latter was not more than 2 billion years old. Thus the oldest of all 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. Supernovas are of particular interest because their luminosity is so predictable that astronomers use them to measure distances in the universe. To evaluate also to what SpeedSpeed Our universe is expanding.
Theories have been validated and others need to be changed?
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 it left behind occurred when our universe was only 2.3 billion years old. The first analyzes seem to confirm that it indeed has the same intrinsic luminosity as the closest ones astronomers already know. It suffices to emphasize that, pending further validation, the distance and expansion rate measurements do not need revision.
What researchers also hope is that by studying all these ancient supernovae, they can better understand the mechanisms of star formation and the end of life. “The James Webb Space Telescope is so sensitive that almost everywhere it finds supernovas. It's a short story WindowWindowWhich opens to our world. “And every time we've done this in the past, we've discovered very interesting things, things we didn't expect.”the astronomers concluded in A NASA press release.
