Our Sun could harbor a black hole – 'without us noticing'

Black holes can indeed exist in stars. A research team has now gained surprising insights into Hawking's stars.

Garshing – The world of research is sometimes full of strange thought experiments. One such experiment was conducted by the late physicist Stephen Hawking in the 1970s. He thought of stars that had a black hole inside them – “Hawking stars” named after him. Although such stars have not yet been discovered, Hawking's theory still inspires scientists to think about the matter.

According to Hawking's theory, Hawking's star harbors a primordial black hole, a small black hole that formed shortly after the Big Bang. One of these could be captured by a newly forming star. A team of scientists led by the Max Planck Institute for Astrophysics (MPA) in Garching has modeled the evolution of “Hawking stars” and gained some fascinating insights. It was your job In the famous Astrophysical Journal published.

Hawking stars have not yet been discovered

“Scientists sometimes ask crazy questions to deepen their knowledge,” says Selma de Mink, head of the MPA's Stellar Research Division. “We don't even know whether such primordial black holes exist or not, but we can still perform an interesting thought experiment,” she adds.

If a newly formed star were to capture a black hole with the mass of an asteroid or a small moon, it would become a “Hawking star.” According to Hawking's theory, the black hole will grow only slowly because the star's streaming luminosity means that only a small amount of gas falls on the black hole.

The MPA team modeled the evolution of such a star, taking into account the different initial masses of the black hole. The astonishing result: If the black hole's mass were small, its existence would not be observed, and the star would be indistinguishable from a regular star.

The Sun could contain a black hole the size of Mercury

“Stars with a black hole at their center can live surprisingly long periods,” comments Earl Patrick Bellinger, study leader. Bellinger has made an interesting new discovery: “Our Sun could also have a black hole at its center, the size of the planet Mercury, without us noticing it.”

The main difference between a regular star and a Hawking star is near the core: the black hole's gravitational pull causes it to become convective. However, this would not be visible on the star's surface. Only the relatively new field of astroseismology can prove this, according to a statement from the MPA. Only at a later stage in a star's evolution, when it becomes a red giant, can the black hole inside it give rise to distinct signatures.

However, according to the research team, more simulations are needed to determine the effects of the central black hole on different types of stars.

Searching for 'Hawking stars' may lead to primordial black holes

So far, neither Hawking stars nor primordial black holes have been discovered. But searching for “Hawking stars” could lead to the discovery of tiny black holes, the research team believes. “Although the Sun is used only as an example here, there are good reasons to believe that ‘Hawking stars’ are common in globular clusters and very faint dwarf galaxies,” emphasizes Matt Kaplan, co-author of the study. From: “This means that” Hawking stars could be a tool for testing the existence of primordial black holes and their possible role in dark matter.

A research team recently discovered the oldest black hole known to date, but it's not small at all. Meanwhile, a well-known mathematician is trying to prove that Stephen Hawking was wrong about the “inner workings” of black holes. (unpaid bill)

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