This Supermassive Black Hole Spent Over a Decade Devouring a Star
A supermassive black hole located in a small galaxy 1.8 billion light-years from Earth continues to feed on the remains of a star that was ripped apart more than a decade ago.
The black hole, described in a paper published in the journal Nature Astronomy, is believed to be eating the same star since 2005. The researchers noted that this black hole meal is taking more than 10 times longer than any other previous episode of a star's death.
"We have witnessed a star's spectacular and prolonged demise," said Dacheng Lin, a research scientist at the Space Science Center in UNH's Institute for the Study of Earth, Oceans, and Space and lead author of the study, in a press release. "Dozens of these so-called tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one."
Tidal disruption events occur when the intense gravity from a black hole causes tidal forces to destroy objects, such as stars, that wander too close. Debris from destroyed objects travels towards the black holes. As this debris get ingested by the black hole, it heats up to millions of degrees and generates a distinct X-ray flare.
These X-ray flares were observed using NASA's Chandra X-ray Observatory, Swift Satellite and ESA's XMM-Newton. The researchers noted that the flares coming from the black hole, dubbed as XJ1500+0154, are super long and have been persistently bright for close to a decade. Other flares previously observed only last for a short time and typically becoming very faint in a year, making the X-ray flare detected at XJ1500+0154 to be unique and intriguing.
The long bright phase of the TDE suggests two possibilities. First, the star being eaten by the black hole was the most massive star to be torn apart. The other possibility includes a smaller star being completely torn apart. The researchers estimate that the black hole's eating supply should be significantly reduced in the next decade and start to fade in the next several years.