A supernova in miniature: Bizarre "micronovas" are exploding in small stars, astronomers say
Nicole Karlis - Yesterday 4:36 PM
For centuries, human beings have been fascinated by supernovas, the violent explosion of a massive star at the end of its life. A supernova in our galaxy lit up the sky for 8 months in 185 A.D., marking humanity's first recorded observation. Since then, songs, ballads, novels and movies have been written about supernovas, emphasizing both their power and mystery.
Twentieth-century astronomers were finally able to understand the phenomenon, cataloguing them into three types. The first type of supernova occurs when a heavy star's core has become saturated with iron created through the nuclear fusion of lighter elements. Once iron fusion begins, the star's core quickly grows dense beyond the point at which atoms can stably exist. At that point, the pressure pushes atoms' electron shells too close to their nuclei, causing them to spontaneously merge. This causes an uncontrolled reaction that compresses the core of the star into either a neutron star or a black hole, while the outer shell blows off at incredible speed. This type of supernova is known as iron-core collapse.
The second type of supernova happens in binary star systems, in which a "dead" white dwarf star — which has ceased fusion, and is slowly cooling — steals gas from its active companion star as they orbit close. After accreting its neighbors' matter for years, the dead white dwarf star may spontaneously start fusion up again, which often triggers a supernova. And then there's the rarely-seen third type, the so-called electron collapse supernova, which was widely theorized for a long time, but observations were only confirmed in 2021.
Now, astronomers believe they've discovered a new type of stellar explosion, similar to a supernova, that occurs when a star dies. It's called a "micronova," a reference to that it occurs in much smaller stars. The details of this new discovery were published in a study in Nature last week.
More:
https://www.msn.com/en-us/news/technology/a-supernova-in-miniature-bizarre-micronovas-are-exploding-in-small-stars-astronomers-say/ar-AAWAAmD
