TESS watched a black hole tear apart a star
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.
Earlier this year, NASA’s TESS spacecraft watched a black hole tear apart a star from start to finish, a cataclysmic phenomenon called a tidal disruption event. On September 26, 2019, NASA released this video of the event.
The blast, named ASASSN-19bt, was found on January 29, 2019 by the All-Sky Automated Survey for Supernovae, a worldwide network of 20 robotic telescopes. 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.
TESS data let us see exactly when this destructive event, named ASASSN-19bt, started to get brighter, which we’ve never been able to do before. Because we identified the tidal disruption quickly with the ground-based All-Sky Automated Survey for Supernovae (ASAS-SN), we were able to trigger multiwavelength follow-up observations in the first few days. The early data will be incredibly helpful for modeling the physics of these outbursts.
Astronomers think the supermassive black hole that generated ASASSN-19bt weighs around 6 million times the sun’s mass. According to a NASA statement:
TESS monitors large swaths of the sky, called sectors, for 27 days at a time. This lengthy view allows TESS to observe transits, periodic dips in a star’s brightness that may indicate orbiting planets.
Bottom line: TESS watched a black hole tear apart a star from start to finish, a cataclysmic phenomenon called a tidal disruption event. Watch a video.