Black holes burst out huge flares of X-rays when they guzzle up matter from their surroundings. But if such flares are spewing forth with clockwork regularity every nine hours, as in the case of a black hole located 250 million light-years away, there’s a significant conundrum.
ScienceAlert.com brings the puzzling news, and astronomers are betting on a dead star that’s playing on the edge of the black hole and trapped on an elliptical orbit around it that lasts for nine hours. Astronomer Andrew King from the University of Leicester in the UK is the main voice sustaining the wild hypothesis, and he published the research in the Monthly Notices of the Royal Astronomical Society.
Thumbs up for GSN 069!
GSN 069 is the name of the galaxy hosting the puzzling black hole. As you might have already guessed, the monster is located at the very centre of the galaxy.
Andrew King explained:
This white dwarf is locked into an elliptical orbit close to the black hole, orbiting every nine hours,
At its closest approach, about 15 times the radius of the black hole’s event horizon, gas is pulled off the star into an accretion disk around the black hole, releasing X-rays, which the two spacecraft are detecting.
Although we’re talking about a supermassive black hole, the beast that powers the GSN 069 galaxy is only about 400,000 times the mass of our Sun.
King’s model claims that while the black hole was making its active accretion process, a red giant star approached too much. The black hole started to gather matter from the star, pushing it into becoming a white dwarf, the remaining core after a star loses all of its nuclear fuel. Instead of heading to complete oblivion by getting swallowed by the black hole, the white dwarf was captured in orbit around it.
King revealed an even more puzzling thing about the star:
It will try hard to get away, but there is no escape.
The black hole will eat it more and more slowly, but never stop.
While the poor white dwarf is trapped for eternity, we have other things to worry about on Earth that will hopefully not last forever, such as the ongoing pandemic.