The Hubble Space Telescope has spotted the most distant single star ever observed, about 28 billion light-years from Earth. Emitted shortly after the Big Bang, the light from the star was amplified by a foreground galaxy and stretched by the expansion of the Universe.
A record detection
The star was nicknamed Earendelan Old English term meaning ” dawning light ‘, and that’s perfectly fitting for a star we’re observing as it was just 900 million years after the start of theUniverse. This makes it by far the most distant individual star ever observed (the previous record holder, a blue supergiant named Icarewas closer to almost 4 billion light-years).
If it took about 12.9 billion years to light upEarendel to reach us here on Terrel’expansion ofUniverse fact that the star is, or rather would be (the star is probably long dead) now at a staggering distance of 28 billion light-years.
As light travels through the cosmos, the expanding Universe stretches its wavelengths, shifting it toward the red end of the spectrum. Calculating this offset can reveal how far away the source was: the higher its value, the greater the distance. In this case, the redshift ofEarendel was 6.2, which is absolutely huge compared to that ofIcarewhich was only 1.5.
The boost from a much closer galaxy
Although even more distant galaxies and whole clusters have been observed, it is much more difficult to distinguish individual stars at this distance. So astronomers got a boost from a much closer galaxy, which warped spacetime with its immense gravity. The light ofEarendel was thus curved and amplified, which made it visible for Hubble.
Taking into account this phenomenon of gravitational lensastronomers were able to estimate thatEarendel had a mass more than 50 times greater than that of the Soleil. While it may not be a lone star, but a binary star system, that in no way diminishes the prowess of detecting it from such a distance.
According to the team responsible for this discovery, recently detailed in the journal Naturethe super powerful space telescope James-Webb could help determine whether it is one or two stars, and also reveal other properties ofEarendelincluding its temperature and spectrum.