When a star strays too close to a black hole, intense tides break it apart into a stream of gas. The tail of the stream escapes the system, while the rest of it swings back around, surrounding the black hole with a disk of debris. This video includes images of a tidal disruption event called ASASSN-19bt taken by NASA’s Transiting Exoplanet Survey Satellite (TESS) and Swift missions, as well as an animation showing how the event unfolded.
Credit: NASA’s Goddard Space Flight Center
Music: "Games Show Sphere 03" from Universal Production Music
The blast, named ASASSN-19bt, was found on Jan. 29 by the All-Sky Automated Survey for Supernovae (ASAS-SN), a worldwide network of 20 robotic telescopes. Shortly after the discovery, ASAS-SN requested follow-up observations by NASA’s Swift satellite, ESA’s (European Space Agency’s) XMM-Newton and ground-based 1-meter telescopes in the global Las Cumbres Observatory network.
The disruption occurred in TESS’s continuous viewing zone, which is always in sight of one of the satellite’s four cameras. This allowed astronomers to view the explosion from beginning to end.
The supermassive black hole that generated ASASSN-19bt weighs around 6 million times the Sun’s mass and sits at the center of a galaxy called 2MASX J07001137-6602251, located around 375 million light-years away in the constellation Volans.
As shown in this animation, the destroyed star may have been similar in size to our Sun. When it approached the black hole, the star broke apart into a stream of gas. The tail of the stream escaped the system, while the rest of it swung back around, surrounding the black hole with a disk of debris.
ASASSN-19bt occurred in TESS’s continuous viewing zone, which is always in sight of the satellite’s fourth camera. Because of this observing strategy, TESS captured ASASSN-19bt from start to finish, providing a new look at a tidal disruption event.
Observations by NASA’s Swift satellite provided the earliest ultraviolet measurements from a tidal disruption to date. This allowed scientists to determine that the temperature dropped by about 50%, from around 71,500 to 35,500 degrees Fahrenheit (40,000 to 20,000 degrees Celsius), over a few days.