Gluttonous Black Hole Swallows Star's Gas Far Faster Than Previously Thought Possible
A certain black hole is more insatiable than expected. Astronomers have discovered a black hole that is consuming gas from a nearby star about 10 times faster than previously thought possible.
The black hole, named P13, can be found on the outskirts of the galaxy NGC7793, which is about 12 million light-years from Earth. Currently, the hungry black hole is sucking up a weight that's equivalent to 100 billion billion hot dogs every minute. That's far faster than expected.
"It was generally believed the maximum speed at which a black hole could swallow gas and produce light was tightly determined by its size," said Roberto Soria, one of the researchers, in a news release. "So it made sense to assume that P13 was bigger than the ordinary, less bright black holes we see in our own galaxy, the Milky Way."
And yet, despite the fact that it should be larger, the black hole is comparatively small. While it's about a million times brighter than our sun, it's not nearly as massive as it should be.
"There's really not a strict limit like we thought, black holes can actually consume more gas and produce more light," said Soria.
The researchers saw that one side of the "donor" star, which contributes gas to the black hole, was always brighter than the other since it was illuminated by X-rays coming from near the black hole. The star appeared brighter and fainter as it went around P13. This allowed the scientists to measure the time it took for the black hole and the donor star to rotate around each other and to eventually work out the black hole's size.
In the end, they found it was less than 15 times the mass of our own sun. This actually makes P13 part of a select group of black holes known as ultraluminous X-ray sources.
"These are the champions of competitive gas eating in the universe, capable of swallowing their donor star in less than a million years, which is a very short time on cosmic scales," said Soria.
The findings are published in the journal Nature.