A discovery of binary stars could be the first step in building a more complete picture of how our galaxy formed, according to astronomers from The Australian National University. The discovery is part of an ambitious 10-year program to scan the entire southern sky every few nights.
The study’s lead author, ANU researcher Dr Giacomo Cordoni, said the Legacy Survey of Space and Time – or LSST – will build an extraordinary “movie of the universe”.
“This survey–run from the Vera C. Rubin Observatory in Chile–will allow us to track billions of stars and galaxies as they change over time. It’s designed to unravel the history of star clusters, galaxies and the Milky Way itself,” Dr Cordoni said.
Using Rubin’s first public dataset, Data Preview 1, 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, which had previously been studied with the Hubble Space Telescope.
The results suggest that while binaries are gradually destroyed or disrupted in the crowded centre, those living in the quieter outskirts can survive–preserving something closer to the cluster’s original population.
This discovery is a crucial new piece of the puzzle of how globular clusters–some of the Milky Way’s oldest inhabitants–formed and evolved.