Astronomers spotted a black hole that's emitting X-ray bursts every nine hours. The astronomers explained that the strange behaviour may have been caused by a dead star orbiting the black hole.
The new study regarding the black hole's strange behaviour was led by astronomer Andrew King of the University of Leicester in the U.K. His findings were presented in a new paper published in the journal Monthly Notices of the Royal Astronomical Society.
Black Holes' X-ray Bursts
A black hole emitting powerful bursts of X-ray flares is a regular occurrence in space. This event occurs when a black hole consumes massive amounts of cosmic matter. As the materials get devoured, they get subjected to intense heat from the centre of the black hole, which could trigger powerful X-ray flare blasts.
King recently came across a black hole emitting X-ray bursts. However, unlike other black holes, the massive cosmic object ejected X-ray flares regularly. According to the astronomer's observations, the black hole's bright and powerful emissions occurred every nine hours.
Wandering Star's Death
The peculiar black hole belongs to a galaxy known as GSN 069, which is about 250 million light-years from Earth. Through follow-up observations, King learned that the black hole is being orbited by a dead star known as a white dwarf. According to King, before turning into a white dwarf, a red giant star wandered close to the black hole. However, instead of falling into the centre of the black hole, the star ended up maintaining an orbit around it.
Due to the star's close orbit around the black hole, its outer layers got stripped and devoured due to the latter's gravitational pull. This quickened the transformation of the red giant into a white dwarf, which is the remaining dead core of the star.
Black Hole Devouring The Star
As noted by King, the dead star orbits the black hole every nine hours. Every time the star gets close to the black hole, material from the former gets sucked into the latter, triggering a regular outburst of X-ray flares.
"This white dwarf is locked into an elliptical orbit close to the black hole, orbiting every nine hours," King explained in a statement. "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."