Researchers have discovered two unique black hole systems in the Gaia catalog that have caused a real surprise. The scientists’ attention was drawn to black holes named BH1 and BH2, around which stars like the Sun orbit – a situation that astronomers have long thought impossible.
Each of these black holes has a mass about 10 times that of the Sun. The peculiarity is their companion stars, which have similar characteristics to the Sun and spin in very wide orbits. This configuration contradicts conventional ideas: usually stars like the Sun don’t survive when their companion turns into a black hole. The end of a massive star’s life is often accompanied by powerful explosions that either push neighboring stars out of the system or completely engulf them.
However, a team of scientists has proposed a mechanism that explains how such systems could have formed. They analyzed the evolution of giant stars whose mass exceeds the solar mass about 80 times. At the end of their lives, these stars generate powerful stellar winds that gradually push a significant amount of their mass out into space. This prevents them from over-expanding, which would cause the smaller companion to be destroyed. The star then goes supernova and leaves behind a black hole.
The scientists also modeled how common such a scenario might be. Their calculations showed that companion stars with sufficiently wide orbits have a real chance to survive this tumultuous process. The key factor is balance: stellar winds should be strong enough to avoid destructive interactions, but not powerful enough to knock a star out of orbit.
The team estimates that there could be hundreds of similar systems in the Gaia data that have not been discovered yet. This discovery demonstrates how complex and amazing nature is, which makes us rethink our ideas about the universe again and again.
The details of the study are published on the arXiv preprint server.
We previously reported on how double black holes arise.
Provided by phys.org
