On September 26, 2019, NASA reported that the Transiting Exoplanet Survey Satellite (TESS) Mission, mankind’s premier planet hunter, recently observed the initial bursts of a tidal disruption event, a world first in the history of our civilization. This cosmic phenomenon of cataclysmic proportions occurs when a black hole tears a star apart, and follow up observations at NASA’s Neil Gehrels Swift Observatory compiled the most detailed look at the early stages of this process.

Artist depiction of a Tidal Disruption Event. Image credit: NASA/CXC/M. Weiss/U. Michigan/J. Miller et al.

Designated ASASSN-19bt, this star-destroying incident was first captured on January 29, 2019 by the ground based All-Sky Automated Survey for Supernovae Network (ASAS-SN), an international effort that surveys the entire visible sky each night with precision 50,000 times the capability of the human eye. ASAS-SN consists of 24 telescopes spanning the globe, and is responsible for discovering a plethora of celestial objects, supernovae included.

As ASAS-SN observed the tidal disruption event, TESS just so happened to share its line of sight. Though primarily concerned with observing transits, or dips in light from distant stars that reveals the presence of exoplanets, TESS managed to spot ASASSN-19bt a week before its light became bright enough to reach the ground based telescopic network.

The Transiting Exoplanet Survey Satellite (TESS) Credit: NASA

Due to the amount of time needed to process the information which TESS only transmits to Earth on a two week interval, the tidal disruption data was not available until March 13, 2019. Fortunately, the ground based telescope network (ASAS-SN) was available to provide follow up observations. After ASASSN-19bt had occurred, TESS’s southern viewing zone remained oriented toward it, continuing to capture data as the tidal disruption event unfolded, enabling researchers to study black holes and their relationship with other celestial objects in a way that was never possible until this year. So thank you, TESS.

Title disruption events are quite rare, occurring once every 10,000 to 100,000 years in galaxies like the Milky Way. To date, astronomers have only observed around 40 tidal disruptions, but never this early before. Discovering remnants of similar happenings will allow astronomers further insight into understanding this unique phenomenon.