An apparent black hole would actually be a boson star, made up of invisible dark matter

In a strange and distant star system, a star similar to the Sun orbits an invisible object, originally defined as a black hole. However, new data suggests it may be the first identified example to date of a “bosonic star” made of dark matter, scientists postulate in a new study. If this discovery is confirmed, many of the mysteries related to the enigmatic dark matter could begin to be revealed.

Based on data from the European Space Agency (ESA) Gaia satellite, astronomers Alexandre Pombo and Ippocratis Saltas have stated in a new study, recently published on arXiv, that observations of a strange stellar system, composed of a star similar to the Sun that orbits around a supposed black hole, could hide a much more revolutionary finding: the black hole would actually be the first bosonic star, made up entirely of dark matter, detected to date in the Universe.

Although little is known about this mysterious star system, scientists have identified a star with a mass almost identical to that of our Sun and a similar chemical composition, orbiting an enigmatic invisible companion, conspicuously more massive: the strange object has about 11 solar masses.

The two objects orbit each other at a distance of 1.4 Astronomical Units (AU), or roughly the distance that Mars orbits the Sun, completing one orbit every 188 days. According to an article published on Space.com and signed by Paul Sutter, an astrophysicist at Suny Stony Brook and the Flatiron Institute in New York, the star’s companion was first thought to be a black hole, as scientific logic would indicate. according to our current knowledge.

Despite this, Pombo and Saltas questioned this supposed certainty, because a black hole of these dimensions should have arisen after the death of an extremely massive star, and it would not be so simple for two objects with the mentioned characteristics to remain in orbit around each other for millions of years.

Consequently, they thought that perhaps this dark orbital companion is something much more exotic, even than a black hole: it could be a structure composed of a group of dark matter particles. As we know, dark matter is an invisible form of matter that makes up most of the mass in every galaxy. Although there is still no solid understanding of its identity and nature, scientists know it exists because of the influence it exerts on other objects.

Dark matter is thought to be evenly distributed in each galaxy, but it is also possible that it accumulates on itself. It would be the case of a new type of bosons, particles that would flood the cosmos and that would have the capacity to form large groups. Some of these clumps could be the size of entire star systems, but others could be much smaller: these tighter clumps of bosonic dark matter could reach the size of a star, hence they have been called bosonic stars.

As befits their composition, boson stars would be completely invisible. Because dark matter does not interact with other particles or with light, we can only detect it through the gravitational influence on its surroundings, such as a normal star orbiting a bosonic star. In the example studied, scientists believe that the information from Gaia could be enough to replace the putative black hole with a boson star, explaining all the observational data.

source: https://arxiv.org/abs/2304.09140