An international team of astronomers has found that massive stars in metal-poor galaxies are just as likely to have close partners as those in our Milky Way. The discovery sheds new light on how massive stars evolve and could provide clues about the earliest stars in the universe.

The Study

Led by researchers from Belgium, the Netherlands, and Israel, the team monitored 139 massive O-type stars in the Small Magellanic Cloud (SMC), a nearby dwarf galaxy. Using the Very Large Telescope (VLT) in Chile, they tracked how these stars accelerated and decelerated over three months—an indication that many were orbiting a companion.

The results, published in Nature Astronomy, showed that more than 70% of the stars displayed velocity changes, a strong sign of binary systems.

Why the SMC Matters

The SMC has a low-metallicity environment, similar to galaxies that existed when the universe was only a few billion years old.

“We used the Small Magellanic Cloud as a time machine,” said Hugues Sana of KU Leuven, explaining that studying stars there helps scientists understand conditions in the early universe.

Implications for Stellar Evolution

Massive stars, often 15 to 60 times the mass of the Sun, burn bright and eventually explode as supernovae, leaving behind black holes. If many of these stars had partners, it raises the possibility that early-universe stars also formed binary systems.

“Perhaps some of those systems end up as two black holes orbiting each other. It’s an exciting thought,” noted Julia Bodensteiner of the University of Amsterdam.

What’s Next

The team plans 16 additional observation rounds to map the orbits, determine stellar masses, and better understand the companions.

“These measurements will give cosmologists and astrophysicists stronger evidence when studying massive binaries in the young universe,” added Tomer Shenar of Tel Aviv University.

Image Source: Google | Image Credit: Respective Owner