Researchers at the Max Planck Institute for Astrophysics have led an international team in a groundbreaking study modeling the evolution of “Hawking stars.” These stars, theorized to harbor captured primordial black holes formed shortly after the Big Bang, exhibit surprisingly long lifetimes similar to regular stars. The potential existence of these stars raises intriguing questions about dark matter.
Selma de Mink, the director of the stellar department at MPA, notes the speculative nature of the concept: “We don’t even know whether such primordial black holes exist, but we can still do an interesting thought experiment.” Primordial black holes, spanning a range of masses, could be crucial for understanding dark matter and seeding supermassive black holes in galaxies.
The possibility of a newly forming star capturing a black hole as small as an asteroid or moon, termed a “Hawking star,” has been explored. The black hole’s slow growth, hindered by outflowing luminosity, leads to an astonishing finding: stars with small black hole masses are nearly indistinguishable from normal stars during their lifetime.
Earl Patrick Bellinger, who led the study, reveals, “Stars harboring a black hole at their center can live surprisingly long.” Even our sun could conceivably host a black hole as massive as Mercury without detection. The primary distinction lies in the star’s convective core, a potential target for detection through asteroseismology, a field probing stellar interiors using acoustic oscillations.
In later stages, during the red giant phase, characteristic signatures may emerge. The upcoming PLATO project could unveil such objects, offering a potential method for detecting primordial black holes. The study emphasizes the need for further simulations to understand the implications of introducing black holes into stars of varying masses and metallicities.
Professor Matt Caplan at Illinois State University highlights the broader implications: “Hawking stars could be a tool for testing both the existence of primordial black holes and their possible role as dark matter.” While the sun serves as an exercise, the potential prevalence of Hawking stars in globular clusters and ultra-faint dwarf galaxies opens new avenues for exploring the mysteries of our cosmic origins.
Source: Max Planck Society