In March 2022, NASA's Hubble Space Telescope discovered the farthest single star ever detected. The star, whose technical designation is WHL0137-LS, is nicknamed "Earendel" from an Old English word that means "rising light" or "morning star." This year, a follow-up observation was made by NASA using James Webb Space Telescope.
New Quest into the Distant Star
Earendel is located in the Sunrise Arc galaxy at a distance of 28 billion light years. It was believed to be 12.9 billion years old, which means that the light we perceive from this star was released when the universe was less than a billion years old.
Earendel was detected due to the combined ability of human technology and nature in a process known as gravitational lensing. Hubble and Webb's telescopes spotted the star due to its alignment behind a fold in space-time produced by massive galaxy cluster WHL0137-08. The galaxy cluster is so huge that it leads to a space warp which acts like a magnifying glass.
Earendel appears only as a single point of light despite the high-resolution infrared imaging of the Webb telescope. Scientists determined that it was magnified by a factor of at least 4,000, thus revealing that the star is extremely small.
As they continued to explore this region in the universe, the scientists did not expect to see any companions of Earendel. However, the Webb telescope was able to detect colors that reveal more information about this star. The universe's expansion stretched the emitted light into wavelengths that are too long for the Hubble telescope to see and are thus detectable only with Webb.
The Near-Infrared Camera (NIRCam) of the James Webb Space Telescope also provides other details about the Sunrise Arc galaxy. These include young star-forming regions and older star clusters that measure only ten light years in diameter.
On each side of the space fold of maximum magnification, these star features are copied by gravitational lens distortion, while the region where stars are formed appears elongated. Tiny dots on either side of this star also represent older, more established star clusters. Astronomers believe this star cluster is gravitationally bound and will likely stay until the present. This gives us a glimpse of how our Milky Way galaxy might look when it was formed 13 billion years ago.
The record for the oldest and most distant single star was previously held by Icarus, which was spotted by Hubble Space Telescope in 2018. Since Earendel surpasses Icarus, our ability to study distant astronomical objects is improving.
READ ALSO: Hubble Captures 12.9-Billion-Year-Old Star Earendel, Oldest Stellar Ancestor Ever Discovered
New Star Details Revealed
The Webb's NIRCam instrument observations reveal that Earendel is a massive B-type star that is more than twice as hot as the Sun and almost a million times brighter. Based on the colors observed by the Webb telescope, scientists assumed that Earendel may have a companion star that is cooler and redder in color. The findings also reveal more information about the star's composition and characteristics.
The information gathered by the Webb telescope reveals more than just the characteristics of Earendel and its galaxy. It also provides new insights into the beginning of the universe.
Experts believe that the details collected by the telescope can help detect the first generation of stars.
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