JERUSALEM, July 21 (Xinhua) — An international team of astronomers has observed a star surviving not one but two encounters with a supermassive black hole, challenging long-held assumptions that a star cannot escape once it has been captured by a black hole.
It is believed that once every 10,000 to 100,000 years, a star will wander too close to the supermassive black hole in the center of its galaxy and get torn apart in a violent event called a tidal disruption. The black hole swallows part of the star and flings the rest into space, creating a bright flare.
The flare from the unlucky star can “light up” the black hole for a few weeks to months, providing astronomers a brief opportunity to study its properties.
In the latest study, the team, led by researchers from Tel Aviv University, observed two nearly identical flares from the same location, two years apart.
The results were published in a July issue of the Astrophysical Journal Letters.
It suggests the star, coded as “AT 2022dbl” was only partially destroyed during the first encounter and returned again, challenging what scientists thought they knew.
The researchers said that the flares are thus more of a “snack” for the supermassive black hole. The black hole takes a bite out of a star in at least two encounters, rather than swallowing it up in one “meal.”
The team is currently waiting to see whether they will observe a third flare after two more years, in early 2026. They said that whether there will be a third flare, astronomers will rewrite the interpretation of the flares and what they can tell about the black holes. ■