Extraordinary Earendel! NASA's Hubble sees most distant star ever

NASA's Hubble space telescope has detected the light of a star that existed within the first billion years after the universe’s birth in the big bang, astronomers said on Wednesday (March 30). It is said to be the farthest individual star ever seen to date.

NASA informed that the newly discovered star, called "Earendel". Scientists have said that the star is so far away its light has taken 12.9 billion years to reach Earth, when the universe was seven per cent its current age.

"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.

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Welch is the lead author of the paper describing the discovery, which is published in the March 30 journal Nature.

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NASA has informed that the discovery was made from data collected during Hubble's RELICS (Reionization Lensing Cluster Survey) programme. The programme was led by co-author Dan Coe at the Space Telescope Science Institute (STScI).

As per NASA, the previous single-star record holder was detected by Hubble in 2018. That star existed when the universe was about four billion years old, or 30 per cent of its current age. At a time that astronomers referred to as "redshift 1.5."

NASA revealed that scientists use the word "redshift" because as the universe expands, light from distant objects is stretched or "shifted" to longer and redder wavelengths as it travels toward us.

Meanwhile, talking about the newly-detected star, NASA said that Earendel's light came from an era called redshift 6.2.

Welch said, "Normally at these distances, entire galaxies look like small smudges, the light from millions of stars blending together."

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The galaxy hosting the star has been naturally magnified and distorted by an effect called gravitational lensing.

"The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that we named the Sunrise Arc," said Welch.

After he studied the galaxy in detail, Welch found that one feature is an extremely magnified star that he called Earendel, which means "morning star" in Old English.

Welch added that Earendel existed so long ago that it may not have had the same raw materials as the stars that exist today.

"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," he said.

Astronomers intend to gaze at the star using the James Webb Space Telescope, Hubble's successor, which is highly sensitive to infrared light from the oldest celestial bodies, in order to confirm Earendel's age, mass and radius.

It has been hypothesized that primordial stars were made solely from the elements forged after the Big Bang: hydrogen, helium and trace amounts of lithium, and should be more massive than stars that exist today.

It remains to be seen if Earendel belongs to these so-called "Population III" stars, but while the probability is small, it is enticing, said Welch.

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(With inputs from agencies)