Astronomers have used the James Webb Space Telescope to take the most detailed image yet of Earendel, the most distant individual star we have ever seen
Space
2 August 2022
Earendel (see arrow) Coe, Welch, Larson et al.
The James Webb Space Telescope (JWST) has taken a new image of the most distant individual star ever seen at nearly 28 billion light years away. At such enormous distances, we can usually only make out entire galaxies, but a lucky coincidence has allowed researchers to spot this star, called Earendel, with the Hubble Space Telescope and then observe it again with JWST on 30 July.
Earendel – which means “morning star” or “rising light” – resides in a galaxy called the Sunrise Arc. It is so named because its light has been stretched into a long curve by the gravity of a galaxy cluster closer to Earth in a process called gravitational lensing. This process also magnified the galaxy by a factor of more than 1000, allowing astronomers to confirm with JWST that Earendel is an individual star and not a cluster of hundreds.
We can see Earendel because it is perfectly aligned with the galaxy cluster to provide the maximum possible magnification. “That’s a really lucky alignment,” says Dan Coe at the Space Telescope Science Institute in Maryland, part of the team that made the new measurements. “Nobody’s ever seen a star this highly magnified, not to mention a galaxy.” Earendel is more than 10 billion light years more distant than the next-furthest star astronomers have seen.
Because light takes time to travel, we are now observing Earendel as it was about 900 million years after the big bang. Stars in the early universe are expected to have different chemical compositions to modern stars, because heavier elements were formed over time in supernovae – not enough supernovae had occurred back then to enrich space with the elements that are so common now.
The next round of JWST observations for Coe’s team, planned for December, should help unveil what Earendel and the Sunrise Arc are made of. “We’re all made of star stuff, but that stuff wasn’t around in the early universe,” says Coe. “This is a rare opportunity to see if the heavy elements were there in this star 13 billion years ago.”
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