ESO/L. Sidewalk
Artist’s impression of a binary system in which a compact star steals the story of his companion
Even massive stars in poor metal galaxies often have nearby partners, such as the massive stars of our Milky Way, rich in metals.
It has been known for 20 years that many massive stars of the Milky Way, galaxy is rich in metals, have a partner. In recent years, it has become clear that the interaction between these partners is important for the evolution of massive stars.
However, so far, astronomers were unsure if massive stars in poor metal galaxies could also be part of a binary system. Now it turns out that This is the case.
In a new one, published in the magazine Nature AstronomyAstronomers used the VERY LARGE TELESCOPE (VLT) in Chile to monitor the speed of massive stars in the small cloud of Magalhães.
“We used the small cloud of Magalhães like a time machine“, He explains Hugues SanaKU LEUVEN Investigator in Belgium. “The small cloud of Magalhães has an environment of metallicity representative of that of distant galaxies, when the universe was only a thousand millions of years.”
“The study of massive stars outside the Milky Way is difficult because the stars are far away and we receive little light of them,” the astronomers say Tomer Shenar e Julia Bodensteiner, jointly lead the Binarity at Low Metallicity project from the Universities of Amsterdam (Netherlands) and Tel-Aviv (Israel), from which this work derives.
Researchers used the Flames concert at ESO VLT in Chile. Flames has 132 optical fibers, each of which can be directed to a different star, which can then be observed simultaneously.
ESO/SANA et al.
Massive stars in the small cloud of Magalhães. Of the stars studied, 70 percent (the laundry diamonds) seem to accelerate and slow down. This indicates the presence of a partner.
Accelerate and slow
For a period of 3 months, researchers observed the acceleration and slowdown of 139 massive stars of the type O in 9 different moments.
These stars have between 15 and 60 times the mass of our sun. They are hot, shine intensely and They end their lives in supernova explosions. In the process, the core of the star collapses in a black hole.
The results show that more than 70% of the stars observed accelerate and slow down. This is a sign of a nearby partner.
“The fact that the massive stars of the small cloud of Magalhães have a partner suggests that The first stars of the universewhich we suspected are also massive, also had partners, ”says Gonzalo HolgadoPostdoctoral researcher at the IAC (Institute of Astrophysics of Canarias) and co-author of the scientific article.
“Perhaps some of these systems end like two black holes to orbit each other. It’s an exciting thinking, ”he says Michael Abdul-Masihpostdoctoral that will soon join the Department of Astrophysics of ULL (Universidad de la Laguna).
Researchers planned to observe the same stars more 16 times in the near future. Your goal is rebuild the precise orbits From binary stars, determine the masses of their components and study the nature and properties of the companion star.
“Using our measurements, cosmologists and astrophysicists who study the young and poor metal universe can then be based on our knowledge of the massive binary stars with greater confidence,” concludes astronoma SARA R. FIGHTPostdoctoral researcher at ULL, who also participated in the study.
