- The James Webb Telescope observed the star WR 124
- This is the first direct observation of this type of star.
- This observation could lead to immense discoveries
- The origin of life may be found in this image
The sky is dotted with stars. In our galaxy the Milky Way alone, there would be between 200 and 400 billion. But all these white dots are not equal. Some stars are very rare, such as the “Wolf-Rayet stars”, with a chance of appearing around one in 200 million.
These stars have the particularity of being very heavy, 25 times the mass of the Sun. During their decline, they emit gas in large quantities, before exploding in the form of a supernovae. This phase of their life lasts only a few moments on the scale of the Universe (a million years at most).
Discovered more than 150 years ago by two French astronomers, Charles Wolf and Georges Rayet, these stars which today bear their names remain a mystery for the scientific world. Rare, they have never been observed directly. But thanks to the arrival in space of the James Webb Space Telescope (JWST) the situation has changed.
More precise and more powerful than its big brother Hubble, it was able to focus its mirror on the star WR 124. The image has just been made public by NASA. This type star « Wolf-Rayet » named after the two French astronomers who made the indirect discovery 150 years ago.
WR 124: a first for history
The star WR 124 observed for the first time by James Webb © NASA/JPL
According to the first declarations of NASA, the star WR 124 was, a few hundred thousand years ago, about 30 times the mass of the Sun. Since then, a third of this weight has been lost in the vacuum of space. As the core of the star begins to weaken, very violent interstellar winds come to detach the outer layers of the star.
The latter will then lose weight, to the weight that in a few thousand years its core will be exposed and explode in a supernova. The ejected matter gathers in space in the form of a “halo” of light easily visible on the images of James Webb.
As it disperses and cools, material that was once part of the star’s core becomes stardust. NASA believes that these “losses” of Wolf-Rayet stars are the cause of the rapid spread of heavy atoms in the Universe.
Scientists have known for years that the heavier a star, the shorter its lifespan. They also know that in the beginning only hydrogen and helium atoms were present in the vacuum of space. The nuclear fusion reaction between these two primordial elements gave rise to the other particles that we know today.
The Wolf-Rayet stars: the missing link?
What researchers fail to understand is how this heavy matter, present above all in the hearts of stars, was able to cross the Universe to end up in all places at the same time. One of the most probable hypotheses is that very heavy stars, of the Wolf-Rayet type, emitted this matter during their end of life.
NASA has yet to study the data transmitted by the James Webb Space Telescope, but this hypothesis could be confirmed in the months and years to come. The implications of such a discovery would be immense. By understanding how “heavy” matter manages to travel in the Universe, scientists hope to trace the thread of the appearance of life on Earth.
The two notions being extremely close – life cannot develop without “heavy” matter – it would then be possible to know how life appeared on Earth, but especially if and where it appeared elsewhere in the Universe.
