The technology for the exploration and observation of the universe is increasingly developed. So much so that Brian Welch and his team of researchers have made an innovative discovery thanks to the Hubble Space Telescope. They have found a star called WHL0137-LS, which they have nicknamed earendel. Its light has taken almost 13.000 billion years to reach us, and we are seeing it when the universe was only 7% of its current age.
In this article we are going to tell you about the characteristics of Earendel, his discovery and much more.
Earendel's discovery
It is impressive to find an individual star at such a distance, but it is possible because of the distortion of space-time that general relativity describes. Hubble has used a little "trick" to take advantage of this phenomenon. Earendel's light has been amplified by the gravity of a massive galaxy cluster called WHL0137-08 that lies between us and the star. This gravitational lensing effect has allowed us to observe this individual star.
In 2016, the galaxy WHL0137-zD1 was initially observed through the RELICS program, which examines lens clusters, and its distorted shape was attributed to the cluster's gravitational pull. This same galaxy regained Hubble's attention in 2019. The gravitational lensing that created this elongated image is the most widespread among those observed, it spans 15 arc seconds and earned the galaxy the nickname "arc of dawn."
The RELICS program has studied 41 clusters, including WHL0137-08, which has been imaged by Hubble's ACS and WFC3 cameras. The cluster is capable of magnifying objects beyond galaxies, such as stars, and two visible smudges in the background of Earendel's image correspond to the same star cluster. The application of numerical models to the Earendel image has facilitated the precise determination of the star's magnification, which is believed to be between one thousand and forty thousand.
Estimates about the star Earendel
Unfortunately, it is impossible to accurately measure the size of the star from such a great distance, although it can be estimated to be less than 2,3 light years. This estimate may seem irrelevant since stars of such a massive size are not known, but it provides confirmation that we are dealing with a single star rather than a star cluster, although it is possible that it could be a double or triple star.
The absolute magnitude of the ultraviolet has allowed us to deduce that Earendel has a mass greater than 50 solar masses, but there is little room to improve this estimate. Its mass is probably tens or hundreds of times that of our own star, the most probable range being between 50 and 100 solar masses.
After analyzing its characteristics for three and a half years, it can be concluded that this phenomenon is not transitory. Although its composition has not been examined, it is believed that Earendel it was born during the early stages of the universe, suggesting that it is made mostly of hydrogen and helium. Its age, however, indicates that it is not a member of the first generation of stars, known as Population III. The discovery of Earendel, the farthest known star, surpasses that of Icarus, which was found in 2018 and is believed to be four billion years old. Icarus is observed through gravitational lensing, but the new James Webb telescope offers the potential to determine Earendel's spectral type and whether it is a binary or multiple system. The difference between the two discoveries is significant.
Importance of discovery
The importance of this discovery lies in perspective and not as an isolated fact. When we want to learn about ancient civilizations we examine the remains they have left behind. By studying these remains, we can learn about their way of life. Similarly, in the vast expanse of the universe, the remnants of stars act like the remnants of an ancient civilization.
Stars go through a life cycle, from birth to evolution and eventual demise, leaving a residue. Stars like the sun become white dwarfs, while the most massive become neutron stars, and the most massive black holes, which is the core where reactions occur. In the end, what is left of a star is nuclear matter. Therefore, we can compare neutron stars, white dwarfs, and black holes to the mummies of the universe.
This analogy allows us to infer that if we come across one of these objects, was once a star with a certain mass that existed for a specific time. Evolution offers us this idea. By discovering such a star, we would be opening a window to the past. This discovery is significant because it allows us not only to acknowledge the existence of civilization but to experience it in its time. Observing the universe, we are able to see at least one star from when it was a young cosmos, at the age of 900 million years.
Other future discoveries
As we have mentioned the sky of the article, the technology for space observation is more and more developing and advancing at high speed. This makes us think about what discoveries we can expect in the future. The James Webb telescope can be used not only to detect these stars but also to obtain their spectra. By doing so, we can gain a better understanding of stellar astrophysics. These first stars, known as Population III stars, they were the stars that formed during a time when resources were scarce.
During the early stages of the universe, the first stars were made mostly of hydrogen and helium, with trace amounts of other elements. These stars had not yet undergone an explosion and there had been no contamination from other elements created by the merger. However, when these stars finally exploded, they were expected to be much more massive than is currently observed. Observing the characteristics of these early stars is of paramount importance, as it confirms our theoretical understanding of the early stages of the universe.
This fulfills a primary goal of Hubble, which was to ensure that our understanding of physical laws and the cosmos aligns with what we actually observe.
I hope that with this information you can learn more about the star and Earendel and their characteristics.