Researchers have unearthed three of the universe’s most ancient stars, residing right within our galactic neighbourhood.
Three stars circling the Milky Way’s halo came into existence 12 to 13 billion years ago.
Situated in the Milky Way’s expansive “halo” — the encompassing cloud of stars encircling the primary galactic disk — these stars were identified by the team of MIT researchers, including several undergraduate students.
Their analysis indicates that these celestial bodies came into being approximately 12 to 13 billion years ago, during the epoch when the earliest galaxies began to coalesce.
Dubbed as “SASS” stars, short for Small Accreted Stellar System stars, the researchers propose that each star once belonged to its own diminutive, primordial galaxy, subsequently assimilated by the burgeoning Milky Way. Presently, these three stars represent the sole remnants of their original galaxies, orbiting the outskirts of our galactic home. The researchers think that more of these ancient stellar survivors may be lurking in these outer reaches.
Anna Frebel, a professor of physics at MIT, said in a press statement, “These primordial stars are undoubtedly present, given our understanding of galaxy formation. They stand as integral components of our cosmic lineage, and we have now unveiled a novel approach to locate them.”
Credits:Image: Courtesy of the researchers
As the researchers continue to reveal analogous SASS stars, they aim to leverage them as proxies for ultrafaint dwarf galaxies, believed to be among the universe’s earliest surviving galaxies. While these distant galaxies persist today, they remain too remote and dim for comprehensive astronomical examination. Given that SASS stars may have originated from comparable primitive dwarf galaxies, yet reside within the Milky Way and are thus much nearer, they present a feasible avenue for unraveling the evolutionary trajectory of ultrafaint dwarf galaxie
