Black hole is observed ‘snacking’ star – 09/09/2023 – Science

Black holes, celestial objects known for their gluttony, usually eat stars unlucky enough to get too close to them in one fell swoop, annihilating them with their enormous gravitational pull. Some, however, tend to snack rather than devour.

Researchers said they have watched a supermassive black hole at the center of a relatively nearby galaxy as it rips chunks out of a star similar in size and composition to our Sun, consuming material equal to about three times the mass of Earth each time the star approaches. as it travels in its oval-shaped orbit.

Black holes are extraordinarily dense objects with gravity so strong that not even light can escape.

The star is located about 520 million light years from our solar system. A light year is the distance that light travels in one year: 9.5 trillion km. It was observed being ravaged by the supermassive black hole at the heart of a spiral galaxy.

As black holes go, this one is relatively small, and is estimated to have a mass a few hundred thousand times that of the Sun. The supermassive black hole at the center of our galaxy, called Sagittarius A*, has about 4 million times the mass of our Sun. Some other galaxies harbor supermassive black holes hundreds of millions of times the mass of the Sun.

Most galaxies have black holes at their centers, and the environment around them can be among the most violent places in the universe.

Most of the data used by scientists in the new study came from NASA’s Neil Gehrels Swift Observatory.

The star has been observed orbiting the black hole every 20 to 30 days. At one end of its orbit, it gets close enough to the black hole that some material from its stellar atmosphere is sucked up, or accreted, each time it passes, but not so close that it is completely swallowed. Such an event is called a “repeated partial tidal disturbance”.

The stellar material that falls into the black hole heats up to around 2 million degrees Celsius, releasing an immense amount of X-rays, which were detected by the space observatory.

“Most likely the star’s orbit will gradually deteriorate and it will get closer and closer to the supermassive black hole until it gets close enough to be completely disrupted,” said astrophysicist Rob Eyles-Ferris of the University of Leicester in England. . He is one of the authors of the study published this week in the journal Nature Astronomy.