An artistic rendering shows a black hole consuming stellar material during a tidal disruption event. The bottom-right images show XJ1500+0154 as observed by optical and X-ray telescopes. Photo by CXC/M. Weiss; X-ray: NASA/CXC/UNH/D. Lin et al, Optical: CFHT
Feb. 6 (UPI) -- When astronomers at the University of New Hampshire first spotted the X-ray source XJ1500+0154, they didn't realize they'd be observing the phenomenon for a decade.
Tidal disruption events, or TDEs, happen when the gravitational pull of a black hole rips apart a star that drifts too close. Some of the stellar material is expelled outward, while the rest is pulled toward the black hole. The material forms an accretion disk around the black hole as it is pulled inward. The disk's intense pressure generates temperatures upwards of several million degrees, generating X-ray emissions that can be measured by satellite observatories.
The multi-wavelength flares emitted during TDEs typically fade after a year or so. The flares emanating from XJ1500+0154 lasted 10 years.
The decade-long tidal disruption event observed by UNH astronomers was 10 times longer than all previously measured TDEs.
"We have witnessed a star's spectacular and prolonged demise," Dacheng Lin, a research scientist at UNH's Space Science Center, said in a news 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."
Two scenarios could explain the long-lasting flare. Scientists either witnessed the largest star ever destroyed by a TDE, or they saw the first star to be entirely destroyed by a black hole.
X-ray observations of the record-breaking TDE -- recorded by NASA's Chandra X-ray Observatory and Swift Satellite, as well as ESA's XMM-Newton -- suggest the black hole eclipsed the Eddington limit, which is thought to regulate the exchange of material flowing in and out of a black hole's accretion disk.
An accelerated black hole growth rate could help explain how supermassive black holes became so large so quickly. Some supermassive black holes were already a billion solar masses just a billion years after the Big Bang.
XJ1500+0154 is still chewing up stellar material and spitting out X-ray emissions, but observations suggest it should begin to fade within the next few years.
Researchers described the record TDE in the journal Nature Astronomy.
