Scientists Gaze into the Heart of a Dying Star for the First Time, Verify Process of Atom Formation

In the vast expanse of the cosmos, a recent observation of an extraordinary supernova, named 2021yfj, has shed new light on the fascinating process of star evolution. This event offers a unique glimpse into the inner workings of massive stars and the role they play in shaping the universe.

Stars are powered by nuclear fusion, a process where lighter atoms are combined into heavier ones, releasing energy. This energy release, fueled by fusion, has been holding up stars against the force of gravity. However, when the core of a massive star becomes full of iron, the great pressure and temperature will make the iron fuse, but this process absorbs energy instead of releasing it, leading to the inevitable collapse of the star's core.

As a star's core keeps burning, the gas outside the core acquires a layered structure, where successive layers record the composition of the progression of burning cycles. The hydrogen cycle, which lasts for millions of years, is followed by the formation of heavier elements such as helium, carbon, oxygen, neon, magnesium, and sulfur. The most massive stars continue to form elements up to neon, oxygen, silicon, and finally iron.

The findings support existing theories about the structure of massive stars at the end of their lives. Each burning cycle is faster than the previous one, with the hydrogen cycle lasting for millions of years, while the silicon cycle takes only a matter of days. This rapid progression leads to the production of the inner layers (neon, oxygen, and silicon) in a mere few hundred years before the star explodes.

The amount and type of elements ejected by supernovae play a critical role in understanding the evolution of the universe and the formation of our world. Oxygen and other elements such as neon, magnesium, and sulfur mainly come from core-collapse supernovae. The explosion of SN2021yfj revealed the material outside the star came from the silicon layer, which forms on a timescale of a few months.

A plausible scenario is that a second star was involved, with its gravity rapidly pulling out the deep silicon layer. The second star near supernova 2021yfj was likely a binary companion that used its gravity to strip away the inner silicon layer. This event, however, poses a challenge for astronomers, as they don't fully understand how a stellar wind could be powerful enough to do this.

Depending on how big the collapsed core is to start with, it will become a neutron star or a black hole. The inner workings of stars cause the universe to change continuously, with stars and planets formed later being different from those formed in earlier times. When the universe was younger, it had much less in the way of "interesting" elements.

The process of a core-collapse supernova explosion sends energy and matter flying outwards, playing a crucial role in the creation of elements and the development of the universe. The study of these events offers valuable insights into the cosmic dance of stars and the ongoing evolution of our universe.