New Delhi — Scientists from Japan have uncovered new insights into the history of our Sun, revealing that it was part of a large-scale migration of stars from the central regions of the Milky Way galaxy billions of years ago.
Research indicates that the Sun originated approximately 10,000 light-years closer to the galaxy’s core than its current position. The study, based on data from the Gaia satellite—which maps the positions, motions, and chemical compositions of over a billion nearby stars—suggests that the Sun was part of an exodus of stars from the galaxy’s central areas between four and six billion years ago.
The findings provide new understanding of the development of the Milky Way’s central bar-like structure, which is believed to feed the galaxy’s central black hole. This structure creates a ‘corotation barrier,’ making it difficult for stars to escape from the galaxy’s core over long distances.
The team compiled a catalogue of 6,594 stars with chemical compositions similar to the Sun, a dataset approximately 30 times larger than previous surveys. Analyses of this catalogue allowed scientists to determine the ages of stars akin to the Sun, revealing that these stars, including our Sun, once resided much closer to the galactic center.
The research raises questions about how the Sun migrated outward. While the galaxy’s bar structure should have prevented stars from traveling such great distances, the key is that the bar may not have existed 4.6 billion years ago when the Sun was formed. Understanding when the bar formed helps scientists trace the galaxy’s evolution over time.
Since the central regions of the Milky Way are much more hostile to life, this migration history offers important clues about the galaxy’s development. Two papers based on this research have been published in the journals Astronomy and Astrophysics, one detailing the catalogue of solar twins and the other exploring the Sun’s migration history.