Can a 'black hole star' solve the mystery of 'little red dots' spotted in the early Universe?

Astronomers on Wednesday announced a new space object called a 'black hole star,' potentially solving the mystery behind the red objects that have been spotted early in the universe.

The object, named MoM-BH-1, looks like a star roughly the size of our solar system. However, it produces around 100 billion times more energy than the Sun, with its enormous power more closely resembling that of a black hole.

A US-led team of astronomers spotted the object using the James Webb Space Telescope. The study, published in the journal Nature, said the object existed about 660 million years after the Big Bang.

Since JWST began operating in 2022, it has detected several extremely bright objects in the early universe. Scientists have called them "little red dots", but their exact nature has remained unclear.

"What exactly these objects are has been one of the most debated topics of the JWST era," lead study author Rohan Naidu of Hawaii University was quoted as saying by AFP.

The researchers were originally studying another mystery — how some galaxies in the young universe became so bright and massive so soon after the Big Bang.

While analysing JWST images, they came across another "little red dot".

Why did scientists think dust was making it look red?

Scientists often assume that extremely red objects in space are surrounded by dust. Dust can make an object appear redder, similar to how smoke from a wildfire can change the colour of the sky.

"When we see something very red in the universe, we often assume that it is surrounded by dust, like soot or ash," said Robert Simcoe, a study co-author from the Massachusetts Institute of Technology.

"The same way that the wildfire smoke from Canada recently made the sky in Boston look bright red, astronomical objects can also appear redder than their intrinsic colour when you see them through a veil of dust," he added.

But the researchers found something unusual when they studied the object's light at different wavelengths. Some wavelengths showed no light at all.

What made the object shine so brightly?

The findings suggested that dust was not responsible for the object's red appearance. Instead, hydrogen gas was affecting the light.

However, this raised another question: how was the object producing such an enormous amount of energy?

"You can't be powering this by nuclear fusion, which is the energy source that sits at the heart of all the stars," Naidu explained.

The researchers then used computer modelling to explore possible explanations. Their simulations suggested that the object is most likely powered by a black hole at its centre, surrounded by a thick layer, or cocoon, of gas.

This combination makes the object look like a giant star even though its energy comes from a black hole.

(With inputs from AFP)