Astronomers Detect a Distant Eruption From a Black Hole 'Eating' a Nearby Star

Thursday, 14 June 2018 - 6:35PM
Space
Black Holes
Astronomy
Thursday, 14 June 2018 - 6:35PM
Astronomers Detect a Distant Eruption From a Black Hole 'Eating' a Nearby Star
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ESO/L. Calçada
Obviously, it's a good thing that we don't have any black holes too close to our solar system, but occasionally we get a good reminder of what exactly that might look like. And it's messy.

A team of astronomers using a number of radio and infrared telescopes, including the National Science Foundation's Very Long Baseline Array (VLBA), recently detected a distant eruption of cosmic materials inside a pair of colliding galaxies collectively known as Arp 299, located about 150 million lightyears away. Upon closer inspection, they discovered that a supermassive black hole at the center of one galaxy was involved.

Specifically, it was a black hole about 20 million times the mass of our sun, and the eruption of cosmic materials was actually the shredded remains of a passing star about twice the size of our sun. It's easy to guess what happened: the star was ripped apart upon getting pulled in by the black hole's gravity, and the team of astronomers were able to directly image this event for the first time.




The act of a star being "spaghettified" as it approaches a black hole's event horizon is known as a "tidal disruption event" (TDE) and scientists have only detected a handful of them over the years. This is the first time any astronomers have been able to directly observe the jet of dead star-stuff as it's being pulled into the black hole. 

And it took a long time for the team to get the full data on the TDE as it was all happening. It was back in 2005 when the first hints of the event were detected, and the team spent over a decade analyzing the stellar material as it moved at one-fourth the speed of light.

The team suspects that black holes "eating" passing stars may be a common occurrence even if we can't see it too often. Part of the reason they stay hidden is because, like what happened in Arp 299 here, much of the visible light was absorbed in the stellar dust, forcing the team to use radio and infrared to monitor the eruption as it happened. 

One of the lead authors of the new research, Seppo Mattila from the University of Turku in Finland, explained it this way in a statement from the National Radio Astronomy Observatory:

Opening quote
"Because of the dust that absorbed any visible light, this particular tidal disruption event may be just the tip of the iceberg of what until now has been a hidden population. By looking for these events with infrared and radio telescopes, we may be able to discover many more, and learn from them."
Closing quote


But again, whether its common or uncommon, let's be grateful that the closest known black hole is over 3,000 lightyears away.

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