Researchers at Lund University in Sweden have made a breakthrough in understanding three stars at the center of our galaxy, the Milky Way. By analyzing high-resolution data from a 10-meter telescope in Hawaii, the team discovered that these stars are unusually young and have a unique chemical composition.

The study, published in The Astrophysical Journal Letters, focused on a group of stars in the nuclear star cluster at the galaxy’s heart. These stars are challenging to study because they are located far from our solar system and obscured by massive dust and gas clouds. Additionally, the presence of numerous other stars in the area makes it difficult to distinguish individual stars.

In a previous study, the researchers proposed the hypothesis that these stars in the middle of the Milky Way might be younger than expected. The recent findings confirm this hypothesis, revealing that the three stars are relatively young, ranging from 100 million to 1 billion years. To put this into perspective, our sun is approximately 4.6 billion years old.

The discovery of young stars in the nuclear star cluster challenges the belief that this region is ancient. It suggests that active star formation occurs in this historically considered ancient part of the Milky Way. However, dating stars located 25,000 light years away from Earth takes time.

To gather data, the researchers utilized high-resolution data from the Keck II telescope in Hawaii, one of the world’s largest telescopes. They also measured the iron content of the stars to verify their findings. Iron is crucial for understanding the galaxy’s evolution, as theories suggest that young stars contain higher levels of heavy elements. The researchers observed the stars’ spectra in infrared light, which can penetrate the dense dust clouds more effectively than optical light. Surprisingly, they found significant variations in the iron levels among the stars.

The wide range of iron levels indicates that the innermost parts of the galaxy are highly inhomogeneous or unmixed. This unexpected finding provides insights into the Milky Way’s center and clues about the early universe’s appearance. The study contributes to our understanding of the early universe and the processes occurring at the heart of our galaxy. It also inspires further exploration and the development of models and simulations related to galaxies and star formation.

Rebecca Forsberg, a researcher in astronomy at Lund University, expresses excitement about the study’s implications. She highlights the significance of studying the center of our galaxy in such detail, which was previously unattainable. Forsberg believes these measurements can provide valuable insights into the formation and development of our home galaxy.

In conclusion, this groundbreaking study sheds light on young stars’ presence in the Milky Way nuclear star cluster. The unexpected findings challenge previous assumptions and contribute to our understanding of the early universe and the intricate processes occurring at the center of our galaxy.

References

• Lund University. (2023, December 5). Astronomers determine the age of three mysterious baby stars at the heart of the Milky Way. Phys.Org; Lund University. https://phys.org/news/2023-12-astronomers-age-mysterious-baby-stars.html
• Thorsbro, B., Forsberg, R., Kordopatis, G., Mastrobuono-Battisti, A., Church, R. P., Rich, R. M., Ryde, N., Schultheis, M., & Nishiyama, S. (2023). A Wide Metallicity Range for Gyr-old Stars in the Nuclear Star Cluster. The Astrophysical Journal Letters, 958(1), L18. https://doi.org/10.3847/2041-8213/ad08b1