What To Know
- In other words, the stars in the S cluster would not follow the usual path of stellar evolution, where nuclear fusion of hydrogen into helium is the main source of energy.
- The researchers’ models show that in regions where dark matter is dense, stars can actually maintain their equilibrium by burning less or no hydrogen, thanks to the energy provided by dark matter.
- This advance could then bring us closer to solving some of the deepest mysteries of the Universe, and help us better understand its nature and its role in the formation and evolution of galaxies.
Astronomers have identified strange stars near the center of our galaxy, the Milky Way. These objects behave in unusual ways and could be influenced by a mysterious substance called dark matter.
What is dark matter?
There black matter remains one of the greatest mysteries of the Universe. Its importance lies in its ability to solve major cosmological puzzles, including the strange rotation speed of galaxies. Without its presence, conventional models of gravity cannot explain why stars at the outer edges of galaxies move as fast as they do. Thus, dark matter is essential to provide the additional mass needed to hold galaxies together and explain their movements. Despite its omnipresence (it represents approximately 27% of the Universe), its composition remains enigmatic, defying our best theories and observational methods. Scientists have proposed various hypotheses about its nature, ranging from exotic particles to large-scale modifications of gravity. However, none of these theories have yet been conclusively confirmed. Recently, researchers have identified a class of stars near the center of the Milky Way that could shed new light on dark matter.
Credits: titoOnz/istock
Immortal stars?
At the heart of the Milky Way lies a fascinating cosmic environment, dominated by a supermassive black hole. This galactic monster About four million times more massive than our Sun, it exerts an astonishing gravitational pull on surrounding stars, called S-type starscausing them to evolve at dizzying speeds. What makes these stars even more mysterious is their unusual behavior and their apparent youthespecially in a region of the galaxy where they would be expected to be older. These objects, located about a light-year from the galactic center, thus seem to defy conventional stellar laws. To explain this conundrum, astronomers have come up with a puzzling hypothesis. Normally, stars shine by burning hydrogen through nuclear fusion, a process that produces the energy needed to counteract their own gravity. S-type stars, they say, seem to draw their energy from a different source: dark matter annihilation. This exotic phenomenon, where dark matter and dark antimatter particles annihilate each other to produce energy, could then keep them “immortal,” thus moving these stars away from the main sequence of the Hertzsprung-Russell diagram. In other words, the stars in the S cluster would not follow the usual path of stellar evolution, where nuclear fusion of hydrogen into helium is the main source of energy. Instead, their apparent youth and unusual behavior could be explained by their reliance on dark matter as an energy sourcethus bypassing conventional stellar processes.
A hypothesis to be confirmed
This idea is supported by a new study backed by computer simulations. The researchers’ models show that in regions where dark matter is dense, stars can actually maintain their equilibrium by burning less or no hydrogen, thanks to the energy provided by dark matter. Future telescopes could allow us to observe this region with unprecedented resolution, which would confirm the theory that dark matter powers stars. This advance could then bring us closer to solving some of the deepest mysteries of the Universe, and help us better understand its nature and its role in the formation and evolution of galaxies.
