ASASSN-19bt was a tidal disruption event (TDE) discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN) project, with early-time, detailed observations by the TESS satellite.
The black hole which caused the TDE is in the 16th magnitude galaxy 2MASX J07001137-6602251 in the constellation Volans at a redshift of 0.0262, around 375 million light years away.
[2][3] Observations in UV light made with NASA's Neil Gehrels Swift Observatory showed a drop in the temperature of the tidal disruption from around 71,500 to 35,500 degrees Fahrenheit (40,000 to 20,000 degrees Celsius) over a few days.
This is the first time such an early temperature drop has been seen in a tidal disruption event.
[3] The transient resulting from the tidal disruption event has been cataloged as AT 2019ahk.