Astronomers watch black hole stretch a star into stellar "spaghetti"
Astronomers have witnessed a rare celestial light show – a star being stretched into “spaghetti” by a black hole. The event occurred over 200 million light-years from Earth over the course of six months, as the dying star was ripped to shreds by immense gravitational forces.
Black holes are famously ravenous objects, gobbling up anything that wanders too close to their incredible gravitational pull. It wouldn’t be a quick and neat death either – because the strength of the forces are proportional to distance, the part of the object facing the black hole is subjected to much stronger gravity than the side facing away. That stretches the object right out like spaghetti – hence the nickname “spaghettification,” although it’s more scientifically known as a tidal disruption event (TDE).
Stars are one object that can meet this fate, and these events are detected periodically as bright flashes of light, which then fade away over a few months or so. The problem is, it’s often hard for astronomers to study what’s going on during this process – the energy released as the material falls into the black hole sends a curtain of dust and debris flying outwards, blocking the view. But in the new event, named AT2019qiz, astronomers managed to see the show from its very early stages, before the veil went up.
“Because we caught it early, we could actually see the curtain of dust and debris being drawn up as the black hole launched a powerful outflow of material with velocities up to 10,000 km/s,” says Kate Alexander, an author of the study. “This unique ‘peek behind the curtain' provided the first opportunity to pinpoint the origin of the obscuring material and follow in real time how it engulfs the black hole.”
ESO’s Very Large Telescope (VLT) and New Technology Telescope (NTT) were trained on the star, observing it over six months in ultraviolet and optical light, X-rays and radio waves. The observations showed for the first time that the flare of light is directly linked to material flowing off the star. It also revealed that the star had roughly the same mass as the Sun, while the black hole had a mass of more than a million Suns.
The researchers hope that this observation can help them interpret what’s going on in future observations of these tidal disruption events.
The research was published in the journal Monthly Notices of the Royal Astronomical Society. An animation of the spaghettification process can be seen in the video below.