CANBERRA, Oct. 10 (Xinhua) -- A world-first discovery of binary stars, pairs of stars orbiting a common center of gravity, could be the first step in building a more complete picture of how our galaxy formed, according to astronomers in Australia.

The discovery is part of the Legacy Survey of Space and Time (LSST), a 10-year program to scan the entire southern sky every few nights, according to a statement released Friday by the Australian National University (ANU).

The LSST will build an extraordinary "movie of the universe," said the study's lead author, ANU researcher Giacomo Cordoni.

The survey, run from the Vera C. Rubin Observatory in Chile, is expected to enable astronomers to track billions of stars and galaxies as they change over time, designed to unravel the history of star clusters, galaxies, and the Milky Way, Cordoni said.

"One thing we're looking at is globular clusters, among the oldest and most crowded star systems in the universe. Each one holds hundreds of thousands of stars packed into a relatively small space, making them natural laboratories to study how stars evolve and interact," he said.

"Our own Milky Way contains over 150 of these clusters, including the spectacular 47 Tucanae, which is visible to the naked eye from the Southern Hemisphere and often used as a benchmark for models of cluster evolution," Cordoni added.

Within these clusters, binary stars play a key role, as they exchange energy with their neighbors, influence whether a cluster survives for billions of years, and can give rise to exotic objects such as luminous blue stars known as blue stragglers, the study showed.

Using Rubin Observatory's first public dataset, ANU astronomers detected binary stars across the outer regions of 47 Tucanae for the first time. They found that the frequency of binaries in the outskirts of the cluster is about three times higher than in the dense central regions. ■