Astronomers have conducted a comprehensive forensic analysis of a star that shattered when it got too close to a supermassive black hole and then ejected its interiors into space. NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton investigated the amount of nitrogen and carbon near the black hole known to break up the star. Astronomers believe these elements formed inside the star before it disintegrated as the star approached the black hole.

“We’re seeing the essence of what used to be stars,” said John Miller of the University of Michigan, who led the research. “The elements left behind are clues we can follow to figure out which star died.”

In recent years, astronomers have found many examples of “tidal interruptions” when the gravitational forces of a massive black hole destroy a star. This causes a flare often seen in optical and ultraviolet light and X-rays as the remnants of the star heat up. This event, called ASASSN-14li, stands out for several reasons.

At the time of its discovery in November 2014, it was the closest tidal disturbance to Earth (290 million light-years) discovered in nearly a decade. Because of this proximity, ASASSN-14li provided an extraordinary level of detail about the destroyed star. Miller’s team applied new theoretical models to better predict the amount of nitrogen and carbon around the black hole compared to previous work.

“These X-ray telescopes could be used as forensic tools in space,” said co-author Brenna Mockler of Carnegie Observatory and UCLA. “The nitrogen-to-carbon ratio we found points to material in the interior of a doomed star that weighs about three times the mass of the Sun.”

The star in ASASSN-14li is thus one of the largest and possibly the most massive stars that astronomers have ever seen torn apart by a black hole.

“ASASSN-14li is exciting because one of the hardest things about tidal disruptions is being able to measure the mass of an unfortunate star, as we’ve done here,” said co-author Enrico Ramírez-Ruiz of the University of California, Santa California. Cruz. . “It’s fascinating to observe a massive star destroyed by a supermassive black hole because larger stars are expected to be much less common than less massive stars.”

Earlier this year, another team of astronomers reported the “Terrible Barbie” event, in which a star they estimated to be about 14 times the mass of the Sun was destroyed by a black hole. However, this has yet to be confirmed as a tidal disturbance, as the estimation of the star’s mass is based primarily on the brightness of the flare, rather than on a detailed analysis of the material around the black hole, as in the case of ASASSN. 14th.

Another exciting aspect of the ASASSN-14li result is what it means for future research. Astronomers have spotted medium-sized stars like ASASSN-14li in a star cluster containing the supermassive black hole at the center of our galaxy. Therefore, the ability to estimate the stellar masses of tidally destroyed stars provides astronomers a way to potentially determine the presence of star clusters around supermassive black holes in more distant galaxies.

Prior to this work, there was a strong possibility that the elements seen in X-rays might have come from gas released during previous explosions of a supermassive black hole. But the pattern of elements analyzed here appears to come from a single star.

An earlier paper published in 2017 by Chenwei Yang of the University of Science and Technology in Hefei, China, used NASA’s Hubble Space Telescope to show that ASASSN-14li contains more nitrogen than carbon, but smaller amounts than Miller’s. He used ultraviolet data from The team discovered this using X-ray data. These authors found that this star is only 0.6 times the mass of the Sun. Source