Primordial black holes formed at an early stage in the evolution of the universe. Their enormous gravity can have devastating effects on stellar systems. They can transfer energy to large binary systems and disrupt their orbits. Like celestial tyrants, their disruption can lead to extreme consequences, such as the ejection and replacement of stars. A new paper explores the interactions of such systems and considers possible ways in which they can be detected. It is believed that black holes may have formed in the first moments after the Big Bang.
They are not the result of the collapse of supermassive stars, but rather arise from fluctuations in the density of matter. High-density regions simply collapse under the influence of their own gravity, forming so-called primordial black holes (PBHs), whose sizes are said to vary from subatomic to larger than the Sun. It is still controversial whether primordial black holes are in fact the source of dark matter in the universe. It is agreed in the astronomy community that PBHs cannot explain all dark matter, but they probably account for up to 10% of dark matter in the planetary mass range (10-7 to 10-3 solar masses). Further analysis is needed to determine whether PBHs constitute part of the dark matter in the universe. Considering large scales, PBHs are indistinguishable from the background of particulate dark matter.
At small scales, the distribution of PBHs in the universe is not as uniform as the background of particulate dark matter, so we need to explore our own new theories. It is difficult to observe PBHs and understand how close the models are to reality, but it is possible to study their interactions with stellar systems. A paper by Badal Bhalla of the University of Oklahoma and a team of astronomers, published on the arXiv preprint server, investigates how PBHs lose energy when interacting with binary star systems. These interactions can lead to one of five possible outcomes: Stiffening – the two bound objects lose energy to a third free object, decreasing their distance.
Softening – the free body transfers energy to the bound system, so that their distance increases but the bond remains. Perturbation – the free body transfers enough energy to the bound system, so the components separate and all objects remain unbound. Capture – the bound object captures the free object. Exchange – the free object transfers enough energy to unbind one of the bound objects, but loses enough energy to become bound to the remaining object. Previous studies have explored softening and breaking, as well as capture models of PBH and binary interactions. The team suggests that strengthening is also unlikely, so they are considering the possibility of alternative models.
They found that the exchange model should result in a population of PBH binaries within the Milky Way, and indeed some observations suggest these may exist. The team also suggests that it may be possible to detect PBHs in binary systems with PBHs of less than solar mass based on the properties of the binary system. Observations are now needed to confirm the model: the discovery of a black hole in a binary system may be possible and would partially confirm the results.
more: https://dx.doi.org/10.48550/arxiv.2408.04697