Supernova 2020tlf
The final moments of a red supergiant’s life before supernova is almost completely unknown. However, a major breakthrough in our understanding of red supergiant evolution came from the discovery of luminous precursor (i.e., pre-explosion) emission prior to the type II supernova (SN) 2020tlf. This was the first time that we had observed pre-SN activity from a red supergiant that then exploded as a normal type II SN. Below is some selected press on this discovery as well as a summary of the paper on SN 2020tlf.
PRESS
Below is a summary of My paper on SN 2020tlf:
Figure 1
Marked in red is SN 2020tlf in its spiral host galaxy NGC 5731 as imaged by the Young Supernova Experiment transient survey.
Figure 2
SN 2020tlf is the first normal type II supernova to have a precursor detection prior to explosion. This emission was detected with the PS1 telescope as it imaged the explosion site for hundreds of days prior to the supernova. A direct image of the precursor emission is shown in the bottom panel after the template image (top) is subtracted from the science image (middle).
Figure 3
Using the pre- and post-explosion imaging of SN 2020tlf, we were able to construct a bolometric light curve sequence (shown in green) of both the progenitor star and the resulting supernova. Prior to explosion (t = 0), we saw luminous emission from the red supergiant progenitor star as it was gearing up for core-collapse.
Figure 4
The first spectrum taken of SN 2020tlf revealed that the explosion’s shockwave had collided with circumstellar gas that the progenitor had expelled right before explosion. Modeling of the narrow emission lines from produced by this process revealed that the progenitor experienced enhanced mass loss right before explosion.
Figure 5
Combining all the observations and modeling of SN 2020tlf and its precursor allowed us to create one of the most accurate pictures of a red supergiant’s final moments to date. Left is an animation showing the progenitor star expelling material before explosion; this gas being the cause of the narrow emission lines in the first spectrum and the luminous pre-SN emission.