This star orbiting a black hole has a composition that surprises scientists

Many stars are present in the universe, and they also have various characteristics. But recently, astronomers have studied a star that should not exist because its composition is very surprising. And that's not all, as it also orbits around a black hole, making the situation exceptional.

Gaia BH2 is a binary system discovered in 2023, composed of a red giant and a black hole. According to scientific studies, this star is composed of alpha elements, which means that it would have formed around 10 billion years ago. But this is not the case, because astronomers at the University of Hawaii have measured and studied the vibrations propagating inside this star with the help of the TESS satellite and discovered that it is only 5 billion years old.

In addition, this star completes a full rotation in 398 days. In other words, it's much faster than most other red giants in the universe. Indeed, as they age and consume their energy, the stars rotate less quickly. And in this case, an external factor may have accelerated this rotation, as explained by Daniel Hey, lead author of the study:

"Young, alpha rich stars are quite rare and puzzling. The combination of youth and ancient chemistry suggests this star didn't evolve in isolation."

To explain this situation, scientists have put forward two hypotheses. The first would be a merger with another star, which would have injected mass into Gaia BH2 and accelerated its rotation, and the second would be the absorption of this matter during the formation of the black hole located near this star. However, this black hole is invisible and still holds many mysteries. Thus, further studies will need to be conducted to better understand this star.