# NGC 1850 BH1 in the Large Magellanic Cloud is two bright stars, not a black hole, spectra show

- Published: 2026-11-13 23:48 UTC
- Section: Sky & Space › Astronomy
- Tags: NGC 1850 BH1, dormant black hole, Large Magellanic Cloud, spectral disentangling, FLAMES spectrograph, Very Large Telescope, rapidly rotating star, binary mass transfer, black hole impostor
- URL: https://realtech.media/news/rt-fb3949a21330cbf59790d231_ngc_1850_bh1/

**Spectral disentangling of VLT FLAMES data showed that a system once read as an 11-solar-mass black hole with a star holds two luminous stars of 1.7 and 5.2 solar masses.**

![NGC 1850 BH1 in the Large Magellanic Cloud is two bright stars, not a black hole, spectra show](https://realtech.media/media/2026/11/5f9ab9192d23b298.jpg)
*universemagazine.com*

A team led by Rhys Seeburger of Liverpool John Moores University has shown that NGC 1850 BH1, a system in the star cluster NGC 1850 in the Large Magellanic Cloud, contains no black hole, as universemagazine.com reports [1]. The system was previously interpreted as a star of about 5 solar masses orbiting a stellar-mass black hole. New spectroscopic data instead reveal two luminous stars, a so-called impostor of a black hole system [1].

## Why the system was taken for a black hole

Massive stars are mostly born and live in binary systems. When one star exhausts its fuel and explodes, a neutron star or black hole remains next to its companion. A black hole that emits almost no X-rays is called dormant, and such objects can be found only through their effect on the motion of the visible star [1].

Models predict about 100,000 such systems in our Galaxy, but only a few dormant black holes are confirmed, including VFTS 243 in the Large Magellanic Cloud and HD 130298 in the Milky Way. Pairs of ordinary stars can mimic the signal, especially after mass transfer, when one star becomes stripped and inflated and can overshadow the light of its companion [1].

In 2022, researchers interpreted NGC 1850 BH1 as a dormant black hole of 11 solar masses orbiting a normal star of 5 solar masses, because one of the objects was invisible. Later studies reached no definite conclusion: the companion could be a compact object or a bright star hidden in a thick disk [1].

## What the new spectra show

The team applied spectral disentangling, a technique that splits the blended light of two stars into separate spectra. It was used on new, sharper observations from FLAMES, a spectrograph of the Very Large Telescope, which cover shorter wavelengths [1].

A relatively cool, inflated star orbits a hotter, more massive companion that rotates quickly, with a projected velocity of about 280 km/s. According to the authors, the simplest explanation of this configuration is earlier mass transfer. The new estimates give the donor star 1.7 solar masses and the bright companion 5.2 solar masses [1].

Some questions remain open. The mass ratio of the two stars is not known precisely, so the system cannot yet be fully described. An earlier study found the companion contributes less than 10% of the light in a certain wavelength range, while this work finds 30%–50% in the same range, and the authors are unsure why [1].

The system matters because it lies in a cluster whose age, composition and distance are well known. The next step is to obtain cleaner spectra, which is difficult because the field is dense and both stars are relatively faint. Such observations are possible only with the Hubble Space Telescope, blue-sensitive long-slit spectrographs such as X-Shooter, or integral-field spectrographs on 8-meter ground-based telescopes [1].

## Sources

1. [universemagazine.com](https://universemagazine.com/chorna-dira-vyyavylasya-zoreyu)
2. [science.mail.ru](https://science.mail.ru/news/60499-predpolagaemaya-chernaya-dyra-okazalas-bystro-vrashayushejsya-zvezdoj)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-fb3949a21330cbf59790d231_ngc_1850_bh1/