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.

Thomas Holoien, of the Carnegie Observatories is lead author of a paper describing the findings, published in September 27, 2019 in The Astrophysical Journal. Holoien said in a statement:

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:

It sits at the center of a galaxy called 2MASX J07001137-6602251 located around 375 million light-years away in the constellation Volans. The destroyed star may have been similar in size to our sun.

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.

Source: Discovery and Early Evolution of ASASSN-19bt, the First TDE Detected by TESS


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November 7, 2019

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