Weird stellar remnant may be from one of the first stars in the universe - Livescience.com

"AS0039 has such an unusual chemical composition that it enables us to probe the nature of the first stars and, in particular, their stellar mass," study co-author Mike Irwin, an astronomer at the University of Cambridge in England, told Live Science. .

Population I stars, like the sun and most other stars in the observable universe, have high metal content, especially iron, and are rich in relatively heavy elements, like calcium and magnesium.

Population II stars, such as AS0039, are much rarer; these metal-poor stars contain only trace amounts of heavy elements.

Although Population III stars have never been detected, astronomers know that the very first stars born in the universe would have been Population III stars, Irwin said.

As a result, all the stars observed today are Population I or II stars, because they formed from the leftovers of the stars that came before them.

However, the first stars in the universe, Population III stars, formed from pure hydrogen, which was the first element created after the Big Bang, Irwin said.

"Population III stars are defined to be the first generation of stars to have formed in the universe and hence were formed from zero metallicity.".

These findings suggest that AS0039 may be a second-generation star that formed out of the remains of a Population III star.

Computer simulations suggested the Population III star that birthed AS0039 likely died in a powerful hypernova explosion.

"We believe that Population III stars were generally more massive than stars that we see today, so it would not be surprising if a Population III star ended up as a hypernova," Irwin said.

The researchers hope the discovery of AS0039 will help astronomers locate more second-generation metal-poor Population II stars, which would, in turn, shed light on the size and distribution of the Population III stars and the role they played in turning the early hydrogen-filled universe into the one we see today.

"AS0039 shows that it is possible to learn about the properties of Population III stars and signposts the way to finding more examples," Irwin said