A New Kind of Star Surrounded by Cosmic Ash Discovered

When stars in a certain mass range run out of fuel, these stars explode, leaving behind a dense core that can no longer fuse. This remnant, called a white dwarf, with abundant hydrogen and helium in its atmosphere, slowly cools down at the background temperature of the universe over several trillion years.

Now astronomers have discovered two new white dwarfs that don’t quite fit this description. According to the study, published in two studies in the Monthly Notices of the Royal Astronomical Society, it is still a mystery how this new type of white dwarf, which, unlike ordinary white dwarfs, has a significant amount of carbon and oxygen in its atmosphere, came about.

A serious challenge to the accepted understanding of stellar evolution

The carbon and oxygen in the atmosphere of two newly discovered white dwarfs are actually ashes released as a result of stars burning helium. which means that under normal circumstances these two white dwarfs should have gotten through this process a very long time ago. In addition to being covered in ash, the fact that these two new types of white dwarfs are much hotter and larger than other white dwarfs may indicate that they may still be burning more helium in their cores.

Professor Klaus Werner, principal investigator of the team that made the discovery, says of their extraordinary discovery: “We normally expect stars with these surface compositions to have finished burning helium in their cores and are on their way to becoming white dwarfs.” states that it poses a serious “challenge” to the understanding of stellar evolution.

Researchers have a hypothesis as to how new types of white dwarfs might have come into existence

Although it is not yet fully understood how they came into existence, researchers have no idea how these strange stars were born. has a hypothesis. Accordingly, the researchers state that white dwarf pairs in close binary systems can attract each other until they collide in some cases, and if the composition of both white dwarfs is correct, this new type of white dwarf may have formed as a result of the collision.

Noting that “white dwarf mergers usually do not lead to the formation of carbon and oxygen-rich stars,” lead author of the study, Dr. Miller Bertolami; He states that they believe that in binary systems formed with very special masses, a white dwarf rich in carbon and oxygen may deteriorate and rise above a helium-rich white dwarf, and that these stars may eventually form.

However, this model does not explain all the observed features of new stars. The research team states that more work is needed to understand the origins of the new types of white dwarfs.

On the other hand, these interesting white dwarfs are not the only ones that have baffled researchers lately. Another recent study discovered ring-system white dwarfs, white dwarf pulsars, and a rather unusual white dwarf that glows brightly in infrared light but cannot be observed in normal light.