Astronomers have revealed that a distant star has managed to survive a close encounter with a distant black hole. According to reports, a distant star’s orbit took it too close to a black hole located at the galaxy GSN 069. Instead of being consumed by the powerful cosmic monster, the star survived the close encounter despite being trapped by the black hole’s monstrous gravity.
The data gathered by NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton suggest that a red dwarf star survived to get too close to a supermassive black hole. Although the star was captured by the gravity, the star survived, kind of.
A press release from the Chandra X-ray Observatory explains that once the red dwarf was captured by the gravity of the black hole, its outer layers content hydrogen were essentially stripped off and careened toward the black hole, leaving the core of the star — known as a white dwarf — behind. The white dwarf is now in a highly elliptical orbit that completes one cycle approximately ever nine hours. The black hole is located around 250 million light-years from Earth.
The star circles the black hole in an oval-shaped path, and at its nearest point to the black hole, the red dwarf is no more than 14 times the radius of the event horizon, a region of a black hole known as the point of no return.
In its closest approach, the black hole extracts matter from the star which essentially releases an explosion of X-rays which is seen by NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton. As the red dwarf orbits the black hole every nine hours, along its journey it emits an X-ray burst at its closest point in its orbit. Scientists expect the white dwarf to be within the range of this black hole for more than a billion years, reducing the loss of mass with each pass it makes around the black hole.
As explained by astronomers, the interactions between the star and the black hole should also emit gravitational waves.
“Because the white dwarf is so close to the black hole, effects from the Theory of General Relativity mean that the direction of the orbit’s axis should rotate with time, or “process” so that multiple orbits make a rosette-shaped pattern. This rotation should repeat every two days and may be detectable with sufficiently long observations,” researchers revealed in a statement.
Astronomers have found many stars that have been completely torn apart by encounters with black holes, but there are very few reported cases where the star likely survived, the Chandra Observatory reports in a statement.
Encounters like this should be more common than direct collisions given the statistics of cosmic traffic patterns, but could easily be lost for a couple of reasons.
First, it can take a more massive, surviving star far too long to achieve an orbit around a black hole for astrophysicists to see repeated bursts. Another problem is that supermassive black holes that are much more massive than the one in the GSN 069 galaxy may instantly swallow a star rather than the star falling into orbits where they periodically lose mass. In these cases, astronomers wouldn’t observe anything.