The Gemini Observatory reports that astronomers have discovered a tiny black hole in the galaxy Messier 101 that can sustain an impressive appetite while consuming material in a neat manner — a feat that astronomers previously thought impossible. The finding affects the search for intermediate-mass black holes.

According to astronomers, the discovery could change our perception of how some black holes consume matter. The finding implies that this particular black hole, thought to be powering the X-ray source’s high-energy light output, is notably lightweight, and, despite the massive amounts of dust and gas being fed to it by a large star, it eats this material in a surprisingly clean manner.

This particular black hole has to eat matter at close to its theoretical limit of consumption to sustain the type of energy output observed by astronomers.

X-ray sources give off high- and low-energy X-rays, which astronomers call hard and soft X-rays. Larger black holes are likely to produce more soft X-rays, while smaller black holes are likely to produce more hard X-rays. Soft X-rays prevail over this particular X-ray source, so astronomer expected that they would discover a large black hole as its energy source. Gemini observations showed that the M101 ULX-1’s black hole is small, and astronomers don’t know why.

Theoretical models suggest that soft X-rays come primarily from the accretion disk, while hard X-rays are usually generated by a high-energy “corona” around the disk. The models show that the corona’s emission power should increase as the rate of accretion approaches the theoretical limit of consumption.

The stature of M101 ULX-1’s black hole implies that the area around the galaxy should, theoretically, be dominated by hard X-rays and appear structurally more complex. However, this isn’t what astronomers observed.

The discovery is another letdown for astronomers looking for conclusive evidence of an “intermediate-mass” black hole in M101 ULX-1. These objects have long escaped detection by astronomers.

To determine the mass of the black hole, astronomers used the Gemini Multi-Object Spectrograph at the Gemini North telescope on Mauna Kea to measure the motion of the companion star. This star emits strong stellar winds, from which the black hole can then draw in material for consumption. This work also revealed that the galaxy’s black hole can draw in more material from the stellar wind than expected.

Additional details are published in the journal Nature.