Primordial Black Holes Could Throw out Stars and Substitute Them

Primordial black holes came into being during the earliest phases of the evolution of the cosmos. Their colossal gravity may be playing havoc in stellar systems. They have the capability needed to transfer energy into wide binary systems unsettling their orbits. Like cosmic bullies their disruption might lead to extreme consequences though like the expulsion of a star, only to be substituted by the black hole itself!

It’s been hypothesized that during the initial moments after the Big Bang, black holes may have formed. They are not the outcome of supermassive stars having collapsed but instead have formed out of variations in the density of matter. Regions with inordinate density would simply collapse under their own gravitational impact forming what have been labelled primordial black holes (PBHs). They are believed to vary in size from subatomic to some that are more enormous than the Sun.

Whether PBHs really do account for dark matter in the cosmos is still up for debate. Among the astrophysical community it is normally accepted that they can simply not account for all dark matter but perhaps account for up to 10% of dark matter in the planetary mass range.

In a paper published by Badal Bhalla (University of Oklahoma) and a team of astronomers, attempt has been made to explore the way primordial black holes can lose energy when interacting with stellar binary systems. Any one of 5 possible outcomes can result from these interactions;

1: Hardening – the two bound objects lose energy to the third free object affecting their separation to lessen;

2: Softening – the free body transfers energy to the bound system affecting their separation to increase but stay bound;

3: Disruption – the free body transfers adequate energy to the bound system that the components become unbound and all objects linger unbound;

4: Capture – the bound objects seize the free object;

5: Exchange – the free object transfers sufficient energy to unbind one of the bound objects and in doing so loses enough energy to become bound to the remaining one.

Prior studies have explored disruption and softening in PBH and binary interactions as has the capture model. The team propose that hardening is also improbable and so explore the prospect of the exchange model. They discover that the exchange model should lead to a population of PBH binaries in the Milky Way and actually some observations hint that they may exist. The team also propose it may be probable to detect PBHs in binary systems with a sub-solar mass PBH by the properties of the system. Observations are now desirable to validate the model.