The Hubble Space Telescope has smashed a record, identifying its most distant star ever. The star is so far away that its light has taken nearly 13 billion years to reach us, meaning it is from the first one billion years after the Big Bang.
Hubble’s previous record for farthest star observed, set in 2018, was for a star from 4 billion years after the Big Bang. So this new finding is a considerable step older and was only observable thanks to a fortuitous cosmic alignment. “We almost didn’t believe it at first, it was so much farther than the previous most distant, highest redshift star,” said astronomer Brian Welch of the Johns Hopkins University in Baltimore, lead author of the paper, in a statement.
The star in question, named Earendel, which means “morning star” in Old English, is massive, coming in at at least 50 times the mass of our sun. It is also millions of times brighter. However, even allowing for its mass and brightness, it is so far away that it was only possible to observe it thanks to a huge galaxy cluster that passed between it and us. The cluster’s gravity is so large that it warps the light coming from the star and acts as a magnifying class.
“Normally at these distances, entire galaxies look like small smudges, the light from millions of stars blending together,” said Welch. “The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that we named the Sunrise Arc.”
Observing this star is not only a neat record-breaker, but because it is so old, studying it can give clues about the composition of the early universe.
“Earendel existed so long ago that it may not have had all the same raw materials as the stars around us today,” Welch explained. “Studying Earendel will be a window onto an era of the Universe that we are unfamiliar with, but that led to everything we do know. It’s like we’ve been reading a really interesting book, but we started with the second chapter, and now we will have a chance to see how it all got started.”
This research paves the way for further investigations of very distant, very ancient stars which will be possible once the James Webb Space Telescope begins science operations this summer.
“With Webb, we may see stars even more distant than Earendel, which would be incredibly exciting,” Welch said. “We’ll go as far back as we can. I would love to see Webb break Earendel’s distance record.”