Astronomers just made a massively exciting discovery – never before seen first generation stars, a generation of cosmic objects that researchers believed was long lost to human history. They are stars that have been around ever since the Big Bang took place, and reside in the brightest galaxy in the universe.
The galaxy itself is now known as CR7, it looks like a big, blue cloud, and is three (3) times more luminous than Himiko, the brightest distant galaxy that researchers have known about until recently. CR7 gets its name from Cristiano Ronaldo, a Portuguese footballer whose initials and jersey number add up to CR7.
The stars, known as Population III stars, are believed to be as bright as they are because they are mostly made out of gases such as hydrogen and helium, but also small traces of lithium. These were the only materials that were available to the first starts in the aftermath of the Big Bang. They differ from modern-day stars such as our Sun as the latter ones have had access to heavier materials such as oxygen, nitrogen, iron and carbon.
The first generation stars are believed to have been hundreds or quite possibly thousands of times bigger than the Sun, and much hotter than any of the stars that came after them, but unfortunately they would have only burned brightly for a short period of time before dying.
Their explosions are believed to have created the materials that modern-day stars are made out of and that are responsible for life as we know it. Experts say they would have exploded as supernovas after roughly two (2) million years, which is not that long of a lifespan for a star.
Astronomers are overjoyed as the Population III stars were believed to be more of a myth than anything else until they were recently discovered with the help of the European Space Observatory’s Very Large Telescope (VLT).
While Population I stars (start with a healthy dose of heavy elements) and Population II stars (stars with lower heave metal content) had both been spotted in the Milky way before, this is the very first time anyone has seen Population III stars.
The discovery was made by a team of astronomers led by David Sobral from the Institute of Astrophysics and Space Sciences at the University of Lisbon in Portugal. They initially started looking for start in a universe roughly 800 million years after the Big Bang. T
hey first found CR7, and within the galaxy, Very Large Telescope instrument such as the X-shooter and SINFONI started picking up on ionised helium emission. This in combination with the absence of heavier materials led the team to conclude that they had indeed found first generation stars.
Sobral gave a statement saying that the discovery was very unexpected and challenged the astronomers. He explained that after pulling apart the layers of the CR7 one by one, the researchers understood that not only had they found the brightest distant galaxy by far, but they also started to realize that it had every characteristic that was expected from Population III stars.
He went on to add that “Those stars were the ones that formed the first heavy atoms that ultimately allowed us to be here. It doesn’t really get any more exciting than this”.
Jorryt Matthee, a second author from the Leiden Observatory in the Netherlands, gave a statement also stressing that calcium in the bones, the carbon in the muscles and the iron in the blood were all formed in the universe by the first generation stars.