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Named Earendel, its light traveled 12.9 billion years to reach us. Rivaling the largest known stars, scientists estimate its mass to be at least 50 times that of our Sun and millions of times brighter than it.
The star holding the previous record had also been observed by Hubble in 2018. But the latter existed in a Universe then 4 billion years old, compared to only around 900 million years after the Big Bang for Earendel .
A major discovery, since the study of the star will allow scientists to better understand the first ages of the Universe, which we know how to describe today by models, but of which we have few observations. direct.
The discovery was published Wednesday in the prestigious scientific journal Nature. ” At first, we hardly believed it. “Said in a press release the main author of this work, Brian Welch, of Johns Hopkins University in Baltimore, United States. It was he who had the privilege of giving his name to this star: Earendel, which means “ morning Star in Old English.
The star ” existed so long ago that it might not have been made of the same raw materials as the stars around us today The researcher explained. These objects are so far away that their light reaches us only very faintly. Just as the sound of a moving object fades away, the light wave gradually stretches and changes from the visible frequency to the naked eye to that of the infrared.
A closer study of the star
With Earendel’s discovery, scientists are indeed reaching the limits of what Hubble can see. This star will thus be a target of choice for the new James Webb Space Telescope, currently being calibrated in space. James Webb will observe this new star this year, said in a press release the European Space Agency (ESA), which operates the telescope with NASA.
Contrary to Hubble, which has only a small infrared capacity, James Webb will operate only in these wavelengths, allowing to go back even further. Until now, only groups of stars could be observed at such a distance, without being able to distinguish a star in particular.
But Earendel had a cosmic help: a phenomenon called gravitational lensing. A cluster of galaxies, located between us and the star, acts as a magnifying glass amplifying the light of the object. The ESA compares this effect to ripples on the surface of the water, which in good weather can create amplified light beams on the floor of a swimming pool. This rare alignment should last for years to come, according to astronomers.
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