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Gaia Survey Points to Sun’s Outward Migration With Thousands of Stellar Twins

A new Gaia-based catalog of 6,594 solar twins points to a coordinated outward trek 4 to 6 billion years ago tied to the Milky Way’s emerging bar.

Overview

  • Two peer-reviewed papers published Mar. 12 in Astronomy & Astrophysics present the Gaia DR3–derived catalog and its age–orbit analysis.
  • The catalog’s age distribution shows a narrow ~2‑billion‑year spike likely formed locally and a broad 4–6‑billion‑year peak that includes the Sun.
  • The authors propose that the Milky Way’s forming central bar allowed stars to cross the corotation barrier, potentially aided by spiral arms and the Sagittarius dwarf galaxy.
  • The findings imply the Sun and many twins migrated roughly 10,000 light‑years from the inner galaxy to the solar neighborhood, helping explain the Sun’s present location.
  • Independent astronomers caution the broad peak may reflect distance‑limited sampling or orbital‑selection effects, leaving the migration timing and mechanism under debate.