Astronomers discover bizarre 'black hole star' using James Webb Space Telescope

Is it a star or a black hole? A recently discovered astronomical object appears to be a bizarre mix of both.

About the size of the solar system and shrouded in a cloud of gas, the object produces 100 billion times the energy of any known star.

The object, spotted with the James Webb Space Telescope (JWST), is so strange astronomers have dubbed it a "black hole star."

And while it is the first of its kind to be described, the researchers who spotted it can already tell it is far from the last.

The discovery, published today in Nature, could help reveal the identity of mysterious "little red dots" detected in images of the early cosmos taken by the JWST.

Lead researcher Rohan Naidu, an astronomer at the University of Hawaii, said the black hole stars had "remarkable physics".

"We are excited to be studying a new kind of astrophysical object," Dr Naidu said.

"There's so much to do."

Strange little red dots may be 'black hole stars'

When JWST started beaming imagery back to Earth, astronomers found something they were not expecting in the data: specks they have named "little red dots", or LRDs.

These dots hail from the very early universe: between roughly 650 million and 1.6 billion years after the big bang.

This research used JWST to investigate one of these little red dots, MoM-BH*-1, more closely.

Light from this dot comes from 660 million years after the big bang, and has travelled across space for more than 13 billion years.

They found that light from the dot had not come from stars or the dust that permeated interstellar space.

Instead, it was likely coming from very dense hydrogen and helium gas.

The researchers ran a series of simulations to come up with an object that could explain the signals they were seeing from JWST.

"It took me a few months of continuously searching for a model that was a good match to the data," Dr Naidu said.

That model is a huge, young black hole, surrounded not by dust or stars like older black holes are, but by pristine gas.

The researchers have called it a black hole star, because it resembles a massive star, but powered by a black hole at its centre.

Nicholas Seymour, an astronomer at Curtin University who was not involved with the study, said the object had roughly a million times the mass of Earth's Sun.

"That sounds enormous, but compared with the billion-solar-mass monsters we see in the early universe, it is relatively small," Dr Seymour said.

The black hole itself would only be about eight times the size of the Sun, but the gas around it would be about the size of the solar system.

"Imagine an object with the mass of a million Suns hidden inside a turbulent cloud stretching across our solar system," Dr Seymour said.

Christian Wolf, an astronomer at the Australian National University who also was not involved with the study, called it "the most exciting black hole to be reported in years of black hole research".

"It shows that the state these black holes are in is unlike anything we have seen traditionally," Professor Wolf said.

"The good thing is, it points us to the environmental conditions in which these early black holes developed their identity and physical nature."

Dr Naidu said that he and other researchers had since studied 100 other little red dots.

"We found that indeed, a gas-enshrouded heart, remarkably similar to MoM-BH*-1, lies at the centre of every little red dot," he said.

Which came first, black hole or star?

Professor Wolf said that the finding added evidence to a changing theory about the universe's formation.

"For a long time most researchers took it for granted that black holes were first seeded by the collapse of massive short-lived stars in the early universe, and then grew from there," he said.

While this does happen in today's universe, the discovery of black hole stars suggests that supermassive black holes can form without surrounding galaxies.

"Here we see a naked black hole evolving into something big, and there is no sign of a galaxy with stars around it," Professor Wolf said.

This adds to the theory that, in the early universe, giant black holes were formed by something other than a collapsing star.

"The black holes seem to come first and then be seeds for galaxy formation around them," Professor Wolf said.

"Again, a new, more powerful telescope shows us that our imagination is curiously limited until we turn it on, get a better view and see more magic than we have deemed plausible."

While JWST discovered these objects, other telescopes like radio telescopes may help to study them further with new streams of data.

Dr Seymour has been using the Murchison Widefield Array and the Australian SKA Pathfinder telescopes in Western Australia to look for black holes from the early universe.

"Our work suggests that we may be able to find many more of these objects, potentially catching black holes at even earlier stages of their growth," he said.

"If so, we could be getting closer to solving one of astronomy's biggest puzzles: how did the first supermassive black holes grow so big, so quickly?"