Hubble Finds Hungry Black Hole Twisting Captured Star Into Donut Shape

This sequence of artist illustrations shows how a black hole can devour a bypassing star:

1. A normal star passes near a supermassive black hole in the center of a galaxy.
2. The star’s outer gasses are pulled into the black hole’s gravitational field.
3. The star is shredded as tidal forces pull it apart.
4. The stellar remnants are pulled into a donut-shaped ring around the black hole, and will eventually fall into the black hole, unleashing a tremendous amount of light and high-energy radiation.

Astronomers using the NASA/ESA Hubble Space Telescope have recorded a star’s final moments in detail as it gets gobbled up by a black hole.

These are termed “tidal disruption events.” But the wording belies the complex, raw violence of a black hole encounter. There is a balance between the black hole’s gravity pulling in star stuff, and radiation blowing material out. In other words, black holes are messy eaters. Astronomers are using Hubble to find out the details of what happens when a wayward star plunges into the gravitational abyss.

Hubble can’t photograph the AT2022dsb tidal event’s mayhem up close, since the munched-up star is nearly 300 million light-years away at the core of the galaxy ESO 583-G004. But astronomers used Hubble’s powerful ultraviolet sensitivity to study the light from the shredded star, which includes hydrogen, carbon, and more. The spectroscopy provides forensic clues to the black hole homicide.

For any given galaxy with a quiescent supermassive black hole at the center, it’s estimated that the stellar shredding happens only a few times in every 100,000 years.

This AT2022dsb stellar snacking event was first caught on 1 March 2022 by the All-Sky Automated Survey for Supernovae (ASAS-SN or “Assassin”), a network of ground-based telescopes that surveys the extragalactic sky roughly once a week for violent, variable, and transient events that are shaping our universe. This energetic collision was close enough to Earth and bright enough for the Hubble astronomers to do ultraviolet spectroscopy over a longer than normal period of time. The Hubble spectroscopic data are interpreted as coming from a very bright, hot, donut-shaped area of gas that was once the star. This area, known as a torus, is the size of the solar system and is swirling around a black hole in the middle.

The results were reported at the 241st meeting of the American Astronomical Society in Seattle, Washington.

[Image Description: Four-panel illustration titled “Black Hole Devours Bypassing Star” showing four stages of a star being shredded by a black hole.]