When we look up at our skies at night, we see a canvas of incredible black that is strewn with the distant fires of countless glittering stars. How did these fiery stars come into being – and where did they come from? The first stars to break the original darkness of the ancient Universe were the mysterious objects that were responsible for our existence – we would not be here if the first stars did not forge literally all atomic elements heavier than helium, fiery hearts. The iron in our blood, the calcium in our bones, the oxygen we breathe, the water we drink, the sand beneath our feat, and the carbon that underlies life on Earth, were created by stars – which burst into piles of freshly minted, heavy, life-sustaining elements that they scream into space when they "die" after burning their needed hydrogen fuel. In May 2019, astronomers at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts announced their new findings that, instead of inflating into the spheres, as scientists once thought, ancient asymmetric supernova explosions may be responsible for sowing bright new baby stars that made life possible on Earth, and wherever else life in the cosmos could exist.
Hundreds of millions of years after the Big Bang of the birth of the Universe, thought to have happened about 13.8 billion years ago, the first generation of stars ignited, illuminating the Universe in the form of giant glowing globes of hydrogen and helium. Within the hot nuclei of this first primordial star, extreme thermonuclear reactions formed the first batch of heavier elements, including carbon, iron, and zinc.
It is suggested that the first stars were probably giant fireballs that quickly lived and died young. The bigger the star; the shorter his life is. Massive stars burn fuel faster than their smaller siblings because they are much hotter. So, they live only a million years, while their less strong species shine brightly for billions – or even trillion – For many years, on hydrogen combustion the main sequence of the Hertzsprung-Russell star diagram . Astrophysicists have for many years assumed that these ancient, massive stars exploded as similarly spherical supernovae.
However, a team of astronomers at MIT and other institutions have now discovered that these first stars may have exploded to break up in a much more powerful and asymmetric explosion, ejecting jets howling into space that were fierce enough to eject heavy atomic elements into the nearby galaxies. These newly discovered elements – the first of their kind in the ancient Cosmos – have served as a precious seed to the second generation of stars, some of whom can still be seen shining in our Universe today.
In a research paper published in the May 8, 2019 issue Astrophysical Journal , orphans report a large amount of zinc in HE 1327-2326 , which is an ancient star survivor that is among the other stars of the Universe. They believe that the star could only have received so much zinc as a result of an asymmetrical supernova explosion that heralded the "death" of one of the first stars to inhabit the primeval Cosmos. The now-defunct, short-lived, first-generation star has thus enriched the nasal cloud of a younger second-generation star with its freshly minted batch of heavier atomic elements.
"When a star explodes, some part of that star is sucked into a black hole like a vacuum cleaner. Only when you have a mechanism, like a jet that can pull out material, can you observe that material later in the next generation star. And we believe that is exactly what could happen here, "Dr. Anna Frebel explained on May 8, 2019 MIT Press Release. Dr. Frebel is an associate professor of physics at MIT and a member of MIT Cowley Institute for Astrophysics and Space Research.
"This is the first observational evidence that such an asymmetric supernova occurred in the early Universe. It changes our understanding of how the first stars exploded," commented Dr. Rana Ezzeddine, who is a postdoc at MIT, and research & # 39; lead author.
The first generation of stars was not like the stars we see today. This is because the first stellar generation was born directly from pristine hydrogen and helium – the two lightest atomic elements in the known Periodic table. Both hydrogen and helium were born in the Big Bang (Big Bang Nucleosynthesis). It is believed that the first stars were both gigantic and extremely bright, so their existence changed our Universe from what was to what is now is.
There are three generations of stars. Our Sun is a member of the Population I, which means it belongs to the youngest star generation. Population III stars are the oldest, forming an intact gas that remains after the Big Bang. In the jargon of astronomers, all atomic elements heavier than helium are called metals. So, the term metal, how astronomers use it is different from the same term when chemists use it. Population II stars are stars that are sandwiched between Populations I and III. These stars are older than our Population I and the Sun, but younger than the first Population III stars. The first stars were depleted of metals, but Population II stars show trace amounts metals forged in the hot hearts of Population III stars. The population and the stars, like our Sun, are the largest metal content. However, this neat classification is a bit misleading. That's why everything stars, regardless of their generation, are rolling balls composed mainly of hydrogen gas.
Because metals can only be produced by process stellar nucleosynthesis, the existence of even trace amounts metals indicates that the earlier Star Population must have existed prior to the emergence of Stars II. There had tp were the population of stars that existed before them to create them metals. Population III stars, who no longer exist in the visible Universe, have left their chemical "traces" in the generation of stars that came after them, and these stellar "prints" speak of that missing original population of the oldest generation of stars.
Astronomers roughly categorize stars as Population I (high) metal content) or Population II (low) metal content). But even the most metal – The poor population of the II star has a small amount metals they discover that their composition is more than just the pristine primeval gas that formed in the Big Bang of the birth of the Universe. The star giants of Population III consisted of only the lightest intact gases: hydrogen, helium, and some lithium. Therefore, the gas that makes up Star III was not "polluted" by heavy metals Forged in the hot hearts of earlier stars. Population III stars initiated a gradual increase in stars metallicity in the younger and younger generations of stars.
Population III stars are usually considered to be born in the clean cradles of unpolluted gas. Numerical computer simulations shed light on the very ancient and mysterious process of star formation, and the extremely short lifespan of first stars. The gigantic stars of Population III did not embark on that good night and exploded noisily in the glowing explosions of the supernova, which drove up supplies of newly formed metals howling loudly into the space between the stars. This made the newborn baby have heavier atomic elements available for inclusion in the giant cold, dark molecular clouds gas and dust that served as unusual nurseries for later generations more metal – Rich stars.
Because the first stars were so massive, they quickly utilized the necessary supply of pristine hydrogen gas – then exploded into pieces of probably incredibly powerful, shiny and violent supernovae. Population III stars burned at a relatively young age by stellar standards. These ancient supernovae were mainly responsible for initiating a significant sea change in the Universe. These star glare completely changed the dynamics of the Universe by warming up. This new heat ionized the surrounding gas.
A lasting legacy of first stars
Dr. Frebel discovers a fairy tale star HE 1327-2326 , In 2005, the star held the title at the time metal -defined star known. This means that it displaced extremely low concentrations of elements heavier than hydrogen and helium, indicating that it was a Population II star. HE 1327-2326 she was born at a time when most of the Universe was heavy metals it had not yet been forged.
"The first stars were so massive that they had to explode almost immediately. The smaller stars that formed as the second generation are still available today, and they preserve the early material left by these first stars. Our star has only an abundance of elements heavier than hydrogen and helium, so we know that the sea was created as part of the second generation of stars, "Dr. Frebel explained on May 8, 2019 MIT Press Release.
"From early observations, people thought that the first stars were not so bright or energetic, and when they exploded, they would not participate much in the re-unification of the Universe. In a sense, we correct this image and depict it; are now strong rivals for contributing to reionization and for havoc in their own little dwarf galaxies, "Dr. Frebel added.
The first supernova to announce the explosive death of the first stars could also be powerful enough to fire their newly formed heavy series metals into nearby "virgin galaxies" that were about to give birth to stars.
Dr. Frebel went on to explain that "Once you have some heavy elements in hydrogen and helium gas, you have a much easier time forming stars, especially small ones. The working hypothesis is that these second-generation stars may form in these polluted virgin systems rather than in the same system like the supernova explosion itself, which is always what we assumed without thinking in any other way. So this opens up a new channel for early star formation. "