Poring over x-ray data spanning 20 years, a team of scientists has witnessed the destruction of three stars via supermassive black holes.

According to Discovery News, the new study, published in the journal Monthly Notices of the Royal Astronomical Society, is significant because such stellar events are quite rare. While every galaxy is believed to have its own supermassive black hole, they usually only devour a star once every 10,000 years.

When the black hole pulls its victim close, the immense gravitational pull is enough to rip the star apart. The more the black hole absorbs, the more massive it becomes and the rapid collection of material also elicits a signature x-ray signal.

The new study comes from the Moscow Institute of Physics and Technology (MIPT) and the Space Research Institute of the Russian Academy of Sciences. The observing astrophysicists relied on two satellites: ROSAT, launched in 1990, and XMM-Newton, which took over for its predecessor in 1999.

"Since a supermassive black hole takes just a few years to fully absorb the captured matter of a destroyed star (typically, this makes up about a quarter of its original mass), observations repeated a decade later should detect significant dimming of an X-ray source. The researchers obtained sky survey data in the 1990s and in the 2000s, so they were able to detect objects whose brightness reduced by at least tenfold," the MIPT reported in a press release.

The astrophysicists noted that they could have observed up to 24 other stellar death events, but that they would need to wait until the 2016 launch of the Spectrum-X-Gamma space observatory to make a positive identification.

"Researchers estimate that several hundred such occurrences will be registered annually with the help of Spectrum-X-Gamma," the MIPT stated. "This will not only allow them to more accurately measure the average frequency of such occurrences in the universe, but also to examine in greater detail the interaction of supermassive black holes with surrounding objects."