Utilizing an extensive catalog of Sun-like stars created by ESA’s Gaia mission, astronomers have uncovered compelling evidence suggesting that our Sun migrated outward with thousands of similar stars approximately 4 to 6 billion years ago. This finding offers significant insights into the formation of the Milky Way’s central bar.
An artist’s impression illustrating the Sun’s movement and its solar twins from the center of the Milky Way galaxy, dating back 4 to 6 billion years. Image credit: National Astronomical Observatory of Japan.
“While terrestrial archaeology studies human history, galactic archaeology explores the vast journeys of stars and galaxies,” stated Daisuke Taniguchi, an astronomer at Tokyo Metropolitan University, along with his colleagues.
“It is established that our Sun formed approximately 4.6 billion years ago, originally over 10,000 light-years closer to the Milky Way’s center than its present location.”
“Research into stellar compositions supports this hypothesis, yet it has historically posed challenges for scientists.”
“Observations indicate a significant bar-like structure at the Milky Way’s center, creating a corotation barrier that restricts stars from escaping far from the center.”
The study aimed to compile a comprehensive catalog of solar twin stars with stellar parameters closely resembling those of the Sun.
“Solar twins are characterized by stellar properties such as effective temperature, surface gravity, and metallicity that closely align with those of the Sun,” the researchers explained.
“By conducting differential analysis between stellar twins—stars with similar stellar parameters—we can achieve exceptional precision in measuring both stellar parameters and chemical abundances.”
The astronomers utilized data gathered by ESA’s Gaia satellite, which contains an extraordinary array of observations from 2 billion stars and celestial objects.
They successfully cataloged 6,594 solar twins, approximately 30 times more than previously documented studies.
This extensive catalog allowed them to construct the most accurate estimates of the ages of these stars, carefully accounting for biases related to the visibility of selected stars.
Upon examining the age distribution, they identified a peak of stars ranging from 4 to 6 billion years old, including our Sun, indicating the existence of similar-age stars situated at comparable distances from the galaxy’s core.
This discovery supports the notion that the Sun’s current location is part of a broader stellar migration pattern rather than a mere coincidence.
This revelation not only enhances our understanding of the solar system but also elucidates the evolution of the Milky Way galaxy itself.
“The corotational barrier produced by the central bar structure of the galaxy would inhibit such extensive migrations,” the researchers noted. “However, if stellar formation was still occurring at that time, the scenario might differ.”
“The age of our solar twin not only indicates when the mass migration happened but also the timeframe related to the formation of the galactic boundary.”
“Regions near the center of a galaxy are generally less conducive to life than those found farther away.”
“Our findings thus unveil critical aspects regarding how our solar system, and consequently our planet, came to occupy a life-supporting region within the galaxy.”
Results were published in the Journal on March 12, 2026, in Astronomy and Astrophysics.
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Daisuke Taniguchi and colleagues. 2026. Gaia DR3 GSP Specification Solar Twin. I. Creation of a Comprehensive Age-Compatible Catalog of Solar Twins. A&A 707, A260; doi: 10.1051/0004-6361/202658913
Source: www.sci.news
