Astronomers from the European Southern Observatory (ESO) have captured a rare light emitted from a star being devoured by a supermassive black hole.
Using ESO's own telescope, together with those from other research organizations around the world, they were able to observe an event known as a tidal disruption event (TDE) - which occurs when a star gets too close to a black hole, being pulled apart, and is "spaghettified."
Researchers also noted that this is the closest TDE reported to date, at a little over 215 million light-years from Earth.
Their findings are published in the Monthly Notices of the Royal Astronomical Society Monday, October 12.
An Unprecedented Observation
Matt Nicholl, lead author of the study, a Royal Astronomical Society research fellow, and lecturer at the University of Birmingham in the United Kingdom, explained in a press release that while black holes "sucking in" nearby stars look like science fiction stuff, this is precisely what happens in a tidal disruption event. They also noted that these events are actually rare and quite difficult to observe.
Using ESO's Very Large Telescope (VLT) and New Technology Telescope (NTT), both installed at the Atacama Desert in Chile, the team of astronomers at these sites focused their sights on a flash of light that occurred especially close to a known supermassive black hole. It allowed them to observe in unprecedented detail what exactly happens as a star "dies" as a supermassive black hole devours it.
Theoretically, astronomers have a general idea of what happens during TDE. Thomas Wevers, ESO Fellow based in Santiago, Chile, explains that when an "unlucky star" gets too close to a supermassive black hole, often sitting at the center of a galaxy, "the extreme gravitational pull of the black hole shreds the star into thin streams of material." Wevers, who was at Cambridge's Institute of Astronomy at the time of their study, adds that the bright flare detected by ESO from the devoured star was the result of its own material falling into the black hole. The star is also spaghettified - the horizontal compression and vertical stretching that makes it look like strands - during the process.
Working Around the Curtain of Dust
One of the difficulties in observing the pulse of light during a tidal disruption event is the curtain of dust and debris that shroud the emitted light. Samantha Oats, a co-author of the study from the University of Birmingham, shares: "We found that, when a black hole devours a star, it can launch a powerful blast of material outwards that obstructs our view."
Researchers were able to observe beyond this visual obstruction because they made the discovery shortly after the star was actually shredded by the supermassive black hole. Kate Alexander, NASA Einstein Fellow from the Northwestern University at the United States, explained that because they were able to capture it early, they were able to see how the debris and dust are drawn up following the black hole's expulsion of stellar material - sending these materials up to speeds of 10,000 kilometers per second. She added that this rare experience provides the first opportunity to detect where these obscuring materials come from.
Officially designating the event as AT2019qiz, researchers observed the TDE located in the Eridanus constellation across six months. Wevers explained that multiple surveys also detected the emission shortly after the TDE that ripped the star apart.
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