Astronomers are confident that they’ve just detected the first black hole gobbling up a neutron star, with one slight but intriguing possibility that the swallowed object was a very light black hole—”much lighter than any other black hole we know about in the Universe.”
“About 900 million years ago, this black hole ate a very dense star, known as a neutron star, like Pac-man—possibly snuffing out the star instantly,” continued theoretical physicist, Susan Scott, Leader of the General Relativity Theory and Data Analysis Group at Australia National University ANU and a Chief Investigator with the ARC Center of Excellence for Gravitational Wave Discovery (OzGrav).
On Wednesday 14 August 2019, gravitational-wave discovery machines in the United States and Italy detected ripples in space and time from a cataclysmic event that happened about 8,550 million trillion kilometers away from Earth.
Scott, with the ANU Research School of Physics, said the achievement completed the team’s trifecta of observations on their original wish list, which included the merger of two black holes and the collision of two neutron stars. “The ANU SkyMapper Telescope responded to the detection alert and scanned the entire likely region of space where the event occurred, but we’ve not found any visual confirmation.”
Scientists are still analyzing the data to confirm the exact size of the two objects, but initial findings indicate the very strong likelihood of a black hole enveloping a neutron star. The final results are expected to be published in scientific journals.
“Scientists have never detected a black hole smaller than five solar masses or a neutron star larger than about 2.5 times the mass of our Sun,” Scott said.
ANU plays a lead role in Australia’s partnership with the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO), which is the most sensitive scientific instrument ever built and comprises twin detectors in the US.
The European Gravitational Observatory has a gravitational-wave detector in Italy called Virgo.
The Daily Galaxy, Max Goldberg, via ANU
Image at top of page: On March 28, 2011, NASA’s Swift detected intense X-ray flares thought to be caused by a black hole devouring a star. In one model, illustrated here, a sun-like star on an eccentric orbit plunges too close to its galaxy’s central black hole.