Earendel: James Webb Space Telescope reveals details of the most distant star in the known universe

The James Webb Telescope (JWST) has begun measuring the most distant star ever detected. 

The star, known as Earendel, was discovered last year by the Hubble Space Telescope but the JWST has now revealed more information about the star. 

Earendel's light has taken around 12.9bn years after the Big Bang created the universe to reach Earth. But because the universe is constantly expanding, the star is situated around 28 billion light years from Earth. 

Hubble spotted the star thanks to gravitational lensing - where the gravity of a massive foreground object acts like a lens. It warps the very fabric of space and time, bending and brightening light from a more distant body as that light passes by. 

The JWST team employed this same strategy by harnessing the space-warping power of a gravity cluster called WHL0137-08 that just so happens to line up with Earendel. 

Now, researchers have enough information to begin characterising the star. 

For example, JWST's NIRCam (Near-Infrared Camera) instrument "reveals the star to be a massive B-type star more than twice as hot as our sun, and about a million times more luminous," Nasa officials wrote in a statement announcing the new Earendel observations.

Earendel was named after a character in J.R.R. Tolkien's "The Silmarillion," a prequel to "The Hobbit" and the "Lord of the Rings" trilogy, and may not be alone in its distant quarter of deep space. 

Based on the star's colours, "astronomers think they see hints of a cooler, redder companion star," Nasa officials wrote. "This light has been stretched by the expansion of the universe to wavelengths longer than Hubble's instruments can detect, and so was only detectable with Webb."

Most big stars like Earendel are part of binary systems, NASA officials noted.

The JWST's observations reveal new information about the Sunrise Arc - the galaxy Earendel belongs to. 

“Earendel existed so long ago that it may not have had all the same raw materials as the stars around us today,” astronomer Brian Welch of the Johns Hopkins University in Baltimore said when the star was first discovered last year. “Studying Earendel will be a window into 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,” he added.

The scope has identified a star-forming region in the galaxy that's thought to be less than five million years old - from our perspective. It also revealed a more established star cluster near Earendel which appears to be gravitationally stable and maybe still lives to this day. 

"The discoveries have opened a new realm of the universe to stellar physics, and new subject matter to scientists studying the early universe, where once galaxies were the smallest detectable cosmic objects," Nasa officials wrote. "The research team has cautious hope that this could be a step toward the eventual detection of one of the very first generation of stars, composed only of the raw ingredients of the universe created in the Big Bang — hydrogen and helium."

However, it is important to note that Earendel is only the furthest star. The oldest star is Methuselah, which is estimated to be 14.45 billion years old.