The most distant known star is called Earendel, and after it was first seen by Hubble thanks to a phenomenon known as gravitational lensing, we can now see its colors thanks to observations made with NASA’s James Webb Space Telescope while discovering fascinating details about this blue supergiant in the first billion years of the universe.
“Hubble gave us a glimpse of Earendel, but the James Webb Space Telescope is now giving us a deep look,” NASA said. “These observations shed light not only on the nature of the star but also on its home galaxy, the Arc of Dawn, and possibly the early Universe itself.”
Located billions of light-years from us in the Sunrise Arc galaxy, Earendel is not just any star. When astronomers first discovered the star in 2022, they named it Earendel (Morning Star) to indicate its presence just before the beginning of the universe.
This star emitted the light we see today about 12.9 billion years ago. So it doesn’t exist until 900 million years after the Big Bang. But due to the phenomenon of the expansion of the universe, Earendel is now 28,000 million light years away from us. It is the most distant star in the universe ever discovered. This record dwarfs the previous record of distant stars discovered by Hubble 4 billion years after the Universe formed.
What did the telescope find out?
Webb’s NIRCam (near-infrared camera) instrument shows the star is a massive B-type star, more than twice as hot as our Sun and about a million times more luminous.
The star is only detectable through gravitational lensing thanks to the combined power of human technology and nature. It is aligned behind a ripple in spacetime produced by the giant galaxy cluster WHL0137-08, so massive that it distorts the very fabric of space itself, creating a magnifying glass-like effect.
Stars as massive as Earendel often appear in pairs but have yet to see a mate. However, the star’s colors suggest otherwise: there must be a cooler, redder companion star.
Anyway, the Webb research team is still analyzing the observational data (for example, they haven’t examined Webb’s NIRSpec data yet), and more information about Earendel and its host galaxy will be released shortly. Astronomers hope this will be a stepping stone to discovering even more distant stars, hoping to see one of the first stars known as Population III stars. By finding out more about them, we can fill in the gaps astronomers have about the early history of the Universe and provide insights into what our Milky Way galaxy looked like billions of years ago.
Since Hubble’s discovery of Earendel, Webb has used this technique to discover other very distant stars, though none as distant as Earendel (officially named WHL0137-LS and discovered by the Hubble Space Telescope in 2022, although everyone is happier with the association). featuring the character created by British writer JR Tolkien for the 1914 poem ‘Eärendel’s Voyage’.
