A Sun-like star located in a galaxy roughly 500 million light-years away is being gradually devoured by a black hole, shedding a mass equal to three Earths on each close pass.
A Sun-like star in a galaxy roughly 500 million light-years away is being gradually devoured by a black hole, shedding a mass equal to three Earths on each close pass.
A star similar to our Sun in a nearby galaxy is gradually being eaten by a small but hungry black hole, losing a mass equal to three Earths each time it passes close.
The discovery by astronomers from the University of Leicester was reported on September 7 in the journal Nature Astronomy and is a "missing link" in our knowledge of black holes that disrupt orbiting stars. It shows that there is a whole beaver of edible stars that have not yet been discovered.
Astronomers' attention was drawn to the star's impending doom by a bright flash of X-ray radiation that appeared to originate in the center of the nearby galaxy 2MASX J02301709+2836050, about 500 million light-years away from the Milky Way. The phenomenon has been named Swift J0230, and was discovered as soon as it occurred for the first time using a new instrument developed by scientists for the Swift Neil Garles Observatory. They quickly set up more observations of it in Swift, and found that instead of fading as expected, it shone brightly for 7-10 days and then suddenly went out, repeating this process about every 25 days.
Similar behavior has been observed in the so-called quasi-periodic outbursts and periodic nuclear transients, in which material from a star is ripped from it by a black hole as its orbit approaches it, but they differ in their outburst frequency, and in what is dominant in the outburst - X-ray radiation or optical light. The regularity of Swift J0230's emissions lies between the two, suggesting that it is the "missing link" between the two types of outbursts.
Using the models proposed for these two types of events as a guide, the scientists concluded that the outbursts of Swift J0230 represent a star the size of our Sun in an elliptical orbit around a low-mass black hole at the center of the galaxy. As the star's orbit brings it close to the black hole's strong gravitational pull, material equal to the mass of three Earths is ripped from the star's atmosphere and heated as it falls into the black hole. The intense heat, around two million mXNUMX, releases a huge amount of X-ray radiation that was first picked up by the Swift satellite.
Now you don't see, now you do! X-ray images of the same spot in the sky before (left) and after (right) the outburst of Swift J0230. These images were taken by the X-ray telescope on the Swift satellite.
Credit: Phil Evans (University of Leicester) / NASA Swift