Sun Migrated from Milky Way Core 4-6 Billion Years Ago

Astronomers have uncovered evidence that the Sun migrated outward from the Milky Way's dense core around 4 to 6 billion years ago as part of a vast group of similar stars, a journey that likely positioned our solar system in a more stable environment conducive to life.

The finding, detailed in two studies published March 12 in Astronomy and Astrophysics, draws from data collected by the European Space Agency's Gaia satellite. A team led by Assistant Professor Daisuke Taniguchi of Tokyo Metropolitan University and Assistant Professor Takuji Tsujimoto of the National Astronomical Observatory of Japan analyzed the satellite's observations of more than two billion stars. They compiled a catalog of 6,594 solar twins, stars that closely match the Sun in temperature, surface gravity and chemical composition, including elevated levels of heavy elements like iron and silicon. This catalog, about 30 times larger than previous surveys, focused on stars within roughly 1,000 light-years of Earth, or about 300 parsecs.

By determining the ages of these twins and correcting for observational biases, such as the tendency to detect brighter stars more easily, the researchers identified a...