The light from the star Earendel takes 12.9 billion years to reach Earth.
REPUBLIKA.CO.ID, JAKARTA — The Hubble telescope found the farthest star. That star is Earendel, a hazy spot of light 900 million years after the Big Bang.
According to astronomers in the journal Naturelight Earendel takes 12.9 billion years to reach Earth due to its redshift rating of 6.2. Hubble’s previous record was for a single star, which had a redshift of 1.5 and was assumed to have existed when the universe was 4 billion years old.
“Typically at this distance, entire galaxies look like tiny smudges, with light from millions of stars converging,” said lead author Brian Welch, an astronomer at Johns Hopkins University.
“The galaxy that hosts this star has been enlarged and distorted by gravitational lenses into a long crescent moon that we named the Rising Sun Arc,” he said.
Closer inspection of the arc reveals some bright spots, but the characteristic light coming from Earendel shows a significant redshift, implying great distances. In a rapidly expanding universe, the higher the redshift, the faster the light source is moving away from us.
The observations were made as part of the Reionization Lensing Cluster Survey, or RELICS, a Hubble initiative led by study co-author Dan Coe of the Space Telescope Science Institute.
Astronomers at RELICS use gravitational lenses, a strange phenomenon in which a large object such as a galaxy cluster bends and focuses light from a more distant object. The lensing effect magnifies distant stars, clusters, and galaxies, producing arc-like images.
The lens object in the case of the Rising Sun’s Bow is WHL 0137-08, a galaxy cluster in the constellation Cetus about 6 million light-years away.
Earendel was discovered as a solitary star system rather than a star cluster by astronomers. “At first, we almost didn’t believe it because it was so much further away than farthest star before, with the highest redshift,” said Welch.
According to the researchers, Earendel has a mass at least 50 times that of our sun and emits millions of times more light. However, there are still many unanswered questions. For example, is it really a solitary star or a multi-star system? Does it contain the same material that closer stars are made of?
Earendel could be the first known example of the first generation of stars created after the Big Bang if it exclusively included the fundamental elements hydrogen and helium.
The Hubble Space Telescope, which is 32 years old, is not capable of solving such problems, but the recently launched James Webb Space Telescope, may be able to help.
“With Webb, we hope to confirm that Earendel is indeed a star, and measure its brightness and temperature,” Coe said.
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