Astronomers have discovered a new type of astrophysical object – a ‘star with a black hole’

The object was discovered using the James Webb Space Telescope as part of the Mirage or Miracle project, which is dedicated to the search for the earliest galaxies.

MoM-BH*-1 existed approximately 660 million years after the Big Bang, when the Universe was still very young.

Initially, it appeared as just another bright red dot. The JWST regularly detects such compact objects at vast distances, and their nature remains one of the major mysteries of modern astronomy.

But the spectrum of MoM-BH*-1 turned out to be unusual even by their standards.

Details

In the object’s light, the researchers detected an extremely pronounced Balmer jump — a sharp change in the spectrum associated with the absorption of light by hydrogen.

Such features are found in stellar atmospheres. However, in the case of MoM-BH*-1, the effect was so strong that it proved extremely difficult to explain it in terms of a typical stellar population.

At the same time, the object showed virtually no signs of heavy chemical elements: its spectrum was dominated mainly by hydrogen and helium.

This presented a puzzling picture: astronomers were faced with something that outwardly resembled a giant stellar atmosphere, yet possessed the energy of an active nucleus.

The scientists tested several scenarios using computer modelling.

The model that best matched the observations was one in which the central energy source is an accreting black hole, surrounded by a huge and extremely dense shell of gas.

It is this gas that absorbs and processes the radiation from the central region, making the entire object appear almost like a single giant star.

However, this does not mean that the black hole’s event horizon is the size of the Solar System. It is the gaseous cocoon surrounding it that is enormous.

Calculations show that the gas surrounding the black hole could extend for tens of astronomical units.

One astronomical unit corresponds to the distance from the Earth to the Sun. By way of comparison, the average distance from the Sun to Pluto is about 40 astronomical units.

In other words, such a system could indeed have been comparable in size to the Solar System.

At the same time, according to the models, the central black hole could have had a mass of around a million or more times that of the Sun. The exact estimate remains uncertain, as dense gas can seriously distort the spectral features that are usually used to measure the mass of black holes.

Usually, the very red colour of a distant source is attributed to dust, which absorbs shorter-wavelength radiation.

But for MoM-BH*-1, scientists have proposed a different explanation.

The black hole may be surrounded by a layer of hydrogen so dense that the gas itself becomes almost opaque and alters the shape of the outgoing spectrum.

Thus, the object appears red not necessarily because of a huge amount of cosmic dust — a giant hydrogen shell may play a significant role.

The discovery may have implications far beyond this single unusual object.

Since the launch of the JWST, astronomers have regularly been finding so-called ‘little red dots’ in the early Universe. They are compact, very bright and numerous in the young Universe, but virtually disappear in later epochs.

Scientists are still debating exactly what lies inside these objects.

The authors of the new study suggest that at least some of the red dots may be similar to MoM-BH*-1 — young black holes literally buried within dense gas envelopes.

If this hypothesis is confirmed, it will help us understand how black holes were able to grow so rapidly in the first few hundred million years after the Big Bang.

Despite the striking name ‘star with a black hole’, the interpretation of MoM-BH*-1 has not yet been definitively proven.

The researchers themselves note that the model used is simplified. It shows that a system comprising an accreting black hole and a dense gaseous cocoon can explain the object’s unusual spectrum, but does not rule out all possible alternatives.

It is therefore more accurate to regard MoM-BH*-1 as a strong candidate for a new type of astrophysical source, rather than as a definitively established new class of celestial bodies.

Why this is important

Surprisingly massive black holes already existed during the first few hundred million years of the Universe’s existence. Astronomers have long struggled to explain how they managed to grow so rapidly.

‘Stars with black holes’ may reveal one of the missing stages in this process: a young black hole finds itself surrounded by vast reserves of dense gas, actively accreting matter and rapidly increasing its mass.

If similar objects do indeed prove to be common among the mysterious red dots detected by the JWST, astronomers will have to seriously rethink our understanding of the birth and growth of the first black holes.

Source

Study: Rohan Naidu et al. A gas-enshrouded and gas-reddened black hole at cosmic dawn

Journal: Nature, 2026.