SN 2019zrk, a bright SN 2009ip analog with a precursor

We present photometric and spectroscopic observations of the Type IIn supernova SN 2019zrk (also known as ZTF 20aacbyec). The SN shows a >100 day precursor, with a slow rise, followed by a rapid rise to M approximate to -19.2 in the r and g bands. The post-peak light-curve decline is well fit with an exponential decay with a timescale of similar to 39 days, but it shows prominent undulations, with an amplitude of similar to 1 mag. Both the light curve and spectra are dominated by an interaction with a dense circumstellar medium (CSM), probably from previous mass ejections. The spectra evolve from a scattering-dominated Type IIn spectrum to a spectrum with strong P-Cygni absorptions. The expansion velocity is high, similar to 16 000 km s(-1), even in the last spectra. The last spectrum similar to 110 days after the main eruption reveals no evidence for advanced nucleosynthesis. From analysis of the spectra and light curves, we estimate the massloss rate to be similar to 4 x 10(-2) M-circle dot yr(-1) for a CSM velocity of 100 km s(-1), and a CSM mass of 1 M-circle dot. We find strong similarities for both the precursor, general light curve, and spectral evolution with SN 2009ip and similar SNe, although SN 2019zrk displays a brighter peak magnitude. Different scenarios for the nature of the 09ip-class of SNe, based on pulsational pair instability eruptions, wave heating, and mergers, are discussed.

Automated summary

We present observations of the Type IIn supernova SN 2019zrk, which shows a precursor and prominent undulations in the light curve. The interaction with a dense circumstellar medium dominates both the light curve and spectra.