The Hubble Space Telescope has discovered the most distant star ever observed: dubbed Earendel, its light has traveled 12.9 billion years to reach us.
Scientists estimate its mass, rivaling that of the largest known stars, to be at least 50 times that of our Sun and millions of times brighter than it.
The star that holds the previous record was also observed by Hubble in 2018. However, the latter existed in a universe that was then 4 billion years old, compared to only about 900 million years after the Big Bang for Earendel, the researchers said.
The discovery was published in the prestigious journal Nature on Wednesday.
“At first we almost didn’t believe it,” said lead author Brian Welch, of Johns Hopkins University in Baltimore, US, in a statement.
He was privileged to give this star a name: Earendel means “morning star” in Old English.
The star “existed so long ago that it may not have been composed of the same raw materials as the stars around us today,” the researcher explained.
“The study of Earendel will open a window into a period of the universe that we are unfamiliar with, but which led to everything we know today,” he added.
This star will therefore be a prime target for the new James Webb Space Telescope, which is currently being calibrated in space. James Webb will observe this new star this year, the European Space Agency (ESA), which operates the telescope with NASA, said in a press release.
As the sound of a moving object fades, the light wave gradually expands, changing from the frequency visible to the naked eye to that of infrared.
Unlike Hubble, which has little infrared capability, James Webb will only operate in those wavelengths, allowing us to go even further back.
Until now, only groups of stars could be observed at such a distance, without being able to distinguish a specific star.
But Earendel had a cosmic help: a phenomenon called gravitational lensing. A galaxy cluster that sits between us and the star acts like a magnifying glass, magnifying the object’s light.
ESA compares this effect to ripples on the water surface, which can create amplified rays of light on the bottom of a swimming pool in good weather.
This rare alignment should persist for many years to come, according to astronomers.