The sun and thousands of its twins migrated across the Milky Way just in time

2 days ago

The Sun formed 4.6 billion years ago near the Milky Way's center and migrated about 10,000 light-years outward.
Its chemical composition indicates it couldn't have formed at its current location, requiring crossing a galactic barrier.
A corotation barrier, created by the Milky Way's central bar, typically blocks inner galaxy stars from migrating outward.
Only ~1% of stars from the Sun's presumed birthplace could breach this barrier within 4.6 billion years.
Using Gaia satellite data, researchers identified 6,594 'solar twin' stars near Earth with similar mass and metal makeup.
Age distribution of solar twins shows two peaks: a local group ~2 billion years old and a migrated group 4–6 billion years old.
Some scientists caution the broad peak might be a statistical artifact due to sample selection biases.
The team argues the barrier may not have been fully formed during migration, possibly aided by the galactic bar's growth.
Migration could have been propelled by gravitational forces from the forming bar, spiral arms, and the Sagittarius dwarf galaxy.
The exact timescales remain uncertain, reflecting the dynamic nature of galaxy dynamics research.

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