The ferocious black hole devours three times as many stars as Earth every time it passes

The massive explosion of X-rays discovered by astronomers at the University of Leicester suggests that matter three times the mass of Earth is burning up in… Black hole.

A star like our Sun in a nearby galaxy is gradually being eaten by a small but ravenous black hole, losing the mass equivalent to three terrestrial planets each time it passes by.

The discovery by astronomers at the University of Leicester was reported on September 7 in the journal Nature astronomy It provides the “missing link” in our knowledge of black holes that disrupt the stars they orbit. It indicates that there is a whole population of stars in the process of being consumed that are still undiscovered.

The team received support from the UK Space Agency and the UK Science and Technology Facilities Council (STFC).

Discovery details

Astronomers were alerted to the star’s impending doom by a bright X-ray flash that appears to be coming from the center of nearby galaxy 2MASX J02301709+2836050, about 500 million light-years away from the galaxy. milky way. The asteroid has been named Swift J0230, and was observed the moment it first occurred using a new instrument developed by scientists for the Neil Gehrels Swift Observatory. They quickly scheduled more rapid observations of it, and found that instead of fading away as expected, it would shine brightly for 7 to 10 days and then suddenly turn off, repeating this process about every 25 days.

A visual image of the galaxy in which the new event occurred, taken from archival PanSTARRS data. The X-ray object is found somewhere inside the white circle, and is about the size of a pinhead at 100 metres. The position of a two-year-old supernova is also shown. Credit: Daniele B. malisani/panstars

Connect the missing pieces

Similar behavior has been observed in so-called quasi-periodic explosions and periodic nuclear explosions, where the star has material that is torn apart by a black hole as its orbit approaches it, but they differ in the number of times they erupt, and in whether they explode or not. The explosion in X-rays or optical light is dominant. The regularity of Swift J0230’s emissions decreased between the two, suggesting that it constitutes the “missing link” between the two types of eruptions.

Using proposed models of these two classes of events as a guide, scientists concluded that Swift J0230’s explosion represents a star similar in size to our Sun in an elliptical orbit around a low-mass black hole at the center of its galaxy. . When the star’s orbit approaches the black hole’s intense gravitational pull, matter equivalent to the mass of three terrestrial planets is extracted from the star’s atmosphere and heated as it falls into the black hole. Extreme heat, about 2 million degrees Celsiusreleasing a huge amount of X-rays that were first captured by the Swift satellite.

Now you don’t see it, now you see it! X-ray images of the same location in the sky before (left) and after (right) the eruption of Swift J0230. These images were taken by the X-ray telescope on board the Swift satellite. Credit: Phil Evans (University of Leicester)/NASA SWIFT

Expert insights

Lead author Dr Phil Evans, from the School of Physics and Astronomy at the University of Leicester, said: “This is the first time we have seen a star like our Sun repeatedly being torn apart and consumed by a low-mass black hole. These so-called “frequent and partial tidal disturbance” events are themselves a completely new discovery and appear to fall into two types: those that erupt every few hours, and those that erupt every year or so. This new system falls right in the gap between these elements, and when you run the numbers, you find that the types of objects involved fall into place as well.

Dr Rob Isles-Ferris, who works with Dr Evans on the Swift satellite, recently completed a PhD at the University of Leicester, which involved studying stars disrupted by black holes. “In most of the systems we’ve seen in the past, the star has been completely destroyed,” he explains. Swift J0230 is an exciting addition to the class of turbulent stars in part because it shows us that the two classes of these previously found objects are indeed related, with our new system giving us the missing link.

Illustration of Neil’s Girls Swift Observatory. Credit: NASA

Stay tuned for more discoveries

“Given that we found Swift J0230 within a few months of enabling our new transient catcher, we expect there to be a lot more,” said Dr Kim Page from the University of Leicester, who analyzed the data for the study. Things like this are out there, waiting to be uncovered.

Dr Chris Nixon is a theoretical astrophysicist who recently moved from the University of Leicester to the University of Leeds. He led the theoretical interpretation of this event. His research is funded by the UK Science and Technology Facilities Council and the Leverhulme Trust.

Researchers estimate that the black hole’s mass is about 10,000 to 100,000 times the mass of our Sun, which is very small for the supermassive black holes typically found at the centers of galaxies. The black hole at the center of our galaxy is believed to have a mass of 4 million solar masses, while most of it is located in a region with a mass of 100 million solar masses.

This is the first discovery made using the new Swift satellite transient detector, developed by the University of Leicester team and running on their own computers. When an extreme event causes an X-ray burst in an area of ​​the sky where there were no X-rays before, astronomers call it an astronomical X-ray transient. Despite the extreme events they portend, these events are not easy to find, or at least not quickly – so this new tool was developed to search for new types of transients in real time.

“This type of object was undetectable until we built this new facility, and soon after we found this completely new, never-before-seen event,” Dr. Evans adds. Swift is almost 20 years old, and he has suddenly discovered completely new events that we never knew existed. I think this shows that every time you find a new way to look at space, you learn something new and discover that there is something you didn’t know before.

International cooperation and future prospects

Dr Caroline Harper, Head of Space Science at the UK Space Agency, said: “This is another exciting discovery from the world-leading Swift mission – a low-mass black hole that receives ‘bites’ from a sun-like star as it orbits.” close enough.

“The British Space Agency is working in partnership with NASA In this mission for many years; The UK has led the hardware development of two key scientific instruments and we have provided funding for the Swift Science Data Centre, which we continue to support. We look forward to more insights from Swift about gamma-ray bursts throughout the universe, and the massive events they cause, in the future.

For more on this discovery, see NASA’s Swift Spies sun-like star being consumed bite by bite.

Reference: “Quasi-periodic monthly outbursts resulting from recurring stellar disturbance by a massive black hole” by PA Evans, CJ Nixon, S. Campana, P. Charalampopoulos, DA Perley, AA Breeveld, KL Page, SR Oates, RAJ Eyles-Ferris, D. P. Malesani, L. Izzo, M. R. Goad, P. T. O’Brien, J. P. Osborne, P. Sparovati, September 7, 2023, Nature astronomy.
doi: 10.1038/s41550-023-02073-j