Astronomers discover a new kind of cosmic object: a black hole star

An international team of researchers studying deep-space imagery from the James Webb space telescope has identified what they describe as an entirely unprecedented astrophysical phenomenon. The object, designated as MoM-BH*-1, sits roughly 30bn light years from Earth in the constellation of Cetus, the Whale, and is estimated to have formed about 660m years after the Big Bang.

While investigating the most distant galaxies in the known universe, scientists focused their attention on a remarkably bright red spot that stood out within the telescope’s image archives. The object’s peculiar visual traits initially defied standard astronomical categories. Rather than shining through conventional means, the exotic body produces an extreme level of energy that aligns more closely with black holes than with standard stellar bodies.

Simulations Reveal a Hydrogen Cocoon Around a Massive Black Hole

To understand what could generate such intense red illumination without the standard presence of cosmic dust, researchers ran complex computer simulations. Typically, astronomical objects appear redder when viewed through a dense veil of soot or ash, much like wildfire smoke altering atmospheric colors. However, the light signatures from MoM-BH*-1 failed to match expectations for dust.

When we see something very red in the universe, we often assume that it is surrounded by dust, like soot or ash, explains Simcoe, noting that physical patterns in the light pointed away from standard interstellar debris, according to coverage from MIT.

Instead, the team observed a sharp spectral drop-off known as a Balmer break, a characteristic usually found in the atmospheres of aging stars where dense gas absorbs photons. Yet the break observed in MoM-BH*-1 was deeper than any previously recorded instance, ruling out ordinary stars as the primary source. Furthermore, the light contained almost no signatures of metals, consisting almost entirely of hydrogen and helium.

Simulations indicated that the red hue could be produced by an extremely dense screen of hydrogen surrounding an energy source. To account for the extreme luminosity, researchers introduced an active, accreting black hole into the models. The resulting data suggested a central black hole roughly 100,000 times as massive as the sun, encased in a star-like hydrogen cocoon as large as the entire solar system.

Specifically, the object likely contains a central black hole that is about 100,000 times as massive as the sun, surrounded by a dense, star-like cocoon of hydrogen that is roughly the size of the solar system. Rohan Naidu, Kavli Institute for Astrophysics and Space Research

Implications for Little Red Dots and Supermassive Black Holes

The discovery of MoM-BH*-1 may solve a broader mystery for astronomers studying the early universe. Deep-space surveys conducted by the James Webb Space Telescope have frequently captured numerous mysterious little red dots, or LRDs, in nearly every deep-field image. Researchers now suspect that many of these objects share a similar internal structure.

Naidu notes that every little red dot is consistent with being a black hole star embedded in a generic early galaxy. Rohan Naidu, Massachusetts Institute of Technology

What distinguishes MoM-BH*-1 from other observed red dots is its immense brightness, which allows the black hole star to completely outshine its surrounding host galaxy, providing a clear view of pure black hole star light. Scientists believe these formations may represent a transitional, swaddled phase in cosmic history that serves as the precursor to modern supermassive black holes.

By acting as the seeds for supermassive black holes located at the centers of galaxies like the Milky Way, these objects may have ultimately influenced galactic evolution, dictating when star formation begins and ends across the cosmos.