Population III stars are the first generation of stars that formed in the universe after the Big Bang. They are believed to have formed approximately 13 billion years ago and are made up of only hydrogen, helium, and trace amounts of lithium. These stars are extremely rare and have not been observed directly, but their existence is supported by theoretical models and observations of the oldest stars in the universe.
Population III stars are different from other stars in several ways. They have a much lower metallicity, meaning they have a lower abundance of elements heavier than helium. They are also much larger and hotter than other stars, with masses up to hundreds of times that of our Sun. Additionally, they have shorter lifespans and are more likely to end in a supernova explosion.
The metallicity of Population III stars is extremely low, with some estimates suggesting they may have had less than 0.0001% of the metal content of our Sun. This is because these stars formed before any heavy elements were produced in the universe, and therefore were made up almost entirely of the primordial elements hydrogen and helium.
Studying Population III stars can provide valuable insights into the early universe and the processes that led to the formation of the first stars. These stars played a crucial role in the evolution of the universe, as their deaths through supernova explosions created the first heavy elements, which were then used to form subsequent generations of stars and planets.
It is currently unknown if any Population III stars still exist in the universe. It is possible that some of these stars may have survived until the present day, but they would be extremely rare and difficult to find. However, it is believed that the remnants of these stars can still be observed in the oldest stars in our galaxy, providing important clues about their existence and characteristics.