In a study published in the Monthly Notices of the Royal Astronomical Society, faint supernovae of metal-free first stars were modeled for the first time. This not only made it possible to reveal the patterns of carbon abundance in star formation, but also to get closer to understanding the origin of the chemical elements that make up human bodies.
The first stars are thought to have formed about 100 million years after the Big Bang from the primary gases hydrogen, helium, and light metals. These gases cooled, collapsed and ignited, forming stars 1,000 times more massive than the Sun. The larger the star, the faster they “burn out”. The first stars probably lived for only a few million years – negligible on the scale of the universe, which is about 13.8 billion years old. They are unlikely to ever be seen.
When the first metal-free stars collapsed and exploded into supernovae, they formed heavier elements like carbon. This gave rise to a new generation of stars. One type of second-generation star is called high-carbon metal lean (EMP) stars. To astrophysicists, they are like fossils. Their composition reflects nucleosynthesis or fusion of heavier elements of the first stars.
“We can get indirect measurements to get the mass distribution of metal-free stars from the elemental abundance of low-metal stars,” explains Gen Chiaki, Research Fellow at the Center for Relativistic Astrophysics at the Georgia Institute of Technology.
Chiaki is the lead author of the study that pioneered faint supernovae of metal-free first stars. His work is finally giving scientists a theoretical understanding of their formation.
This kind of research is part of an area called “galactic archeology.” Scientists compare this to searching underground for artifacts that tell about the nature of long-gone societies. For astrophysicists, the nature of long-extinct stars can be determined by their fossilized remains.
“We can’t see the very first generations of stars,” explains study co-author John Wise, assistant professor at the Center for Relativistic Astrophysics at the Georgia Institute of Technology. “It’s important to look at these ‘living fossils’ from the early universe. They have the ‘fingerprints’ of the first stars – chemicals that formed in supernovae from the first stars.
The simulations that scientists have created are showing where the metals come from and how the first stars and their supernovae actually affect these fossils that “have survived to this day.”
The goal of this study by scientists is to find out the origin of elements such as carbon, oxygen, and calcium. They concentrate in repetitive cycles of matter between the interstellar medium and the stars. “Our bodies and our planet are made up of carbon and oxygen, nitrogen and calcium. Our work is very important to find out the origin of these elements that make up people ”- concludes the author of the study.
Recall that Carl Sagan, an American astrophysicist and exobiologist, said back in the last century that phosphorus in human DNA and iron in his blood come from “stellar material.”