(CN) — Astronomers caught a rare glimpse into the last moments of a dying star before it was ripped apart by a supermassive black hole.
Taking place 215 million light-years away in a spiral galaxy in the constellation of Eridanus, the phenomenon known as a tidal disruption event occurred closer to Earth than any previously recorded and may shed new light on one of the more mysterious astronomical events known to occur.
Such an event occurs when a star passes too close to a black hole, allowing the extreme gravity of the black hole to shred the unfortunate passerby in a process known as “spaghettification” — called such because the resulting pieces of stellar matter are stretched into long, relatively thin strands.
As some of these strands are sucked into the black hole, the incredible amount of energy released causes a luminous flare that allows Earth-based observers to detect its whereabouts.
British scientists carried out their investigation over a six-month period in 2019 and described the process in a new study released Monday in the journal Monthly Notices of the Royal Astronomical Society.
By employing UV, optical and X-ray data they were able to chart the path of the debris ejected by the black hole and determine its relative mass and velocity.
"The idea of a black hole 'sucking in' a nearby star sounds like science fiction. But this is exactly what happens in a tidal disruption event," said Matt Nicholl, lead author and a lecturer and Royal Astronomical Society research fellow at the University of Birmingham (U.K.) in a statement. "We were able to investigate in detail what happens when a star is eaten by such a monster."
Astronomers brought out the big guns, so to speak, to observe the rare phenomena. Using the European Southern Observatory’s quite-aptly-named Very Large Telescope and New Technology Telescope, Las Cumbres Observatory’s global telescope network and the Neil Gehrels Observatory Swift satellite, they were able to study the event in far greater detail than would normally be possible thanks to a speedy discovery.
Tidal disruption events are typically obscured by large clouds of dust and debris that get ripped off the passing star by the black hole, making this one, named AT2019qiz, all the more special. In this case the researchers were able to begin their observations before the cloud of dust blocked their view, providing a rare glimpse into one of the universe’s most awesomely destructive events.
"When a black hole devours a star, it can launch a powerful blast of material outwards that obstructs our view," explained Samantha Oates, also at the University of Birmingham, in a statement. "This happens because the energy released as the black hole eats up stellar material propels the star's debris outwards."
This early observation allowed the researchers to follow the path of the material which would normally obstruct their view. According to Nicholl, the engulfed star was approximately equal in mass to our own sun, half of which was lost when it was spaghettified by the black hole, which is more than a million times more massive.
"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 (6,214 miles per second)," said Kate Alexander, NASA Einstein Fellow at Northwestern University (U.S.). "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."
By studying the event, researchers hope to gain a better understanding of supermassive black holes and the exotic way in which matter behaves in their proximity.
Comparing it to the Rosetta Stone, the tablet that allowed experts to decipher ancient Egyptian hieroglyphs, they believe the data derived from this encounter may help provide a better understanding of future tidal disruption dvents which has until now proven elusive.
Future telescopes under development, such as the European Space Agency’s Extremely Large Telescope, should be able to offer even greater insight when they come online by allowing astronomers to view even fainter and more distant phenomena.
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