New study suggests that massive clumps of invisible dark matter may be causing disruptions in the orbits of binary stars, potentially revealing new insights about the elusive nature of the universe. Dark matter, which makes up a significant portion of the mass in galaxies, has long been a topic of study for astronomers. Initially, it was believed that dark matter could be made up of weakly interacting massive particles (WIMPs), but experiments designed to detect these particles have yielded no results. As a result, scientists are exploring alternative models in which dark matter particles are extremely light and exhibit wave-like behavior on larger scales.
A team of Chinese astronomers recently conducted a study on a model of ultralight dark matter and explored ways to detect it through observation. The study, which was published on the preprint server arXiv in April (pending peer-review), delves into the characteristics of this type of dark matter.
Unlike conventional dark matter, which moves through the cosmos like bullets, ultralight dark matter would behave more like a vast, invisible ocean, sloshing around within galaxies. Similar to how oceans can generate waves, the bath of ultralight dark matter would have its own oscillations. These waves could potentially merge into a single group, known as a soliton, which would move interdependently while maintaining its shape.
Although these solitons would be invisible, much like giant rogue waves traversing the galaxy, they would have such a minuscule impact on their surroundings due to their incredibly light composition. However, the researchers discovered that the immense size of these solitons could subtly alter the gravitational environment in their vicinity.
The gravitational pull of the solitons is so feeble that it would have minimal impact on most objects within the galaxy. However, binary star systems with wide separations are only loosely bound by their mutual gravity, making them susceptible to the influence of solitons, which are large enough to alter their orbits.
To explore this phenomenon further, the researchers examined all wide binary pairs listed in the Gaia catalog, which contains information on the billion stars closest to the sun. These pairs were marked for future observations, as any divergence between them could potentially be attributed to the presence of solitons.
By monitoring the evolution of these binary stars, the team realized that they could serve as a highly sensitive tool for investigating ultralight dark matter. In fact, this method might surpass the sensitivity of any Earth-based laboratory specifically designed to detect this type of dark matter. Therefore, if any unusual behavior is observed in binary star systems, it could provide an initial clue regarding the nature of dark matter.