Canberra (dpa) - Researchers have for the first time observed how a black hole devours a neutron star. The gravitational wave observatories Ligo in the US and Virgo in Italy picked up signals from the event on August 14th.
Thus, all three types of events have been observed on the "wish list" of the gravitational wave researchers: the fusion of two black holes, the collision of two neutron stars and how a black hole incorporates a neutron star, such as the participating Australian National University (ANU) ) in Canberra.
"About 900 million years ago, this black hole ate a very dense star, a so-called neutron star, like Pac-Man - and possibly extinguished the star on the spot," said ANU's General Relativity and Data Analysis leader Susan Scott , in the message.
In the video game classic Pac-Man, a hockey puck-shaped figure eats through a labyrinth and destroys points. Like the points of Pac-Man, the neutron star was presumably swallowed up as a whole by the black hole and not, as one would expect, previously torn apart, Scott explained on demand. A rending star should emit light or other radiation as it swirls into the black hole.
Neutron stars are the extremely dense "corpses" of burnt out suns. A teaspoon of neutron star matter weighs around one billion tons. Officially, however, the event is still considered a candidate for a neutron star merger with a black hole. Researchers currently estimate the likelihood of this event to be 99.8 percent.
"Scientists have never discovered a black hole smaller than five solar masses or a neutron star more than 2.5 times the mass of our Sun," Scott explained. "Because of this experience, we are very sure that we have just located a black hole that devours a neutron star."
The exact masses of the observed objects would still be determined. "There is the small but intriguing possibility that the tangled object is a very light black hole - much easier than any other black hole we know in the universe," Scott pointed out. "That would be a fantastic consolation prize."