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

TL;DR

SN 2019zrk is a bright Type IIn supernova with a long precursor, showing strong CSM interaction, high expansion velocities, and spectral evolution similar to SN 2009ip, providing insights into massive star eruptions.

Contribution

This paper reports detailed photometric and spectroscopic observations of SN 2019zrk, revealing its precursor activity, CSM interaction, and spectral evolution, and compares it to similar 09ip-like supernovae.

Findings

Precursor lasted over 100 days with a slow rise.

Peak magnitude around -19.2 in r and g bands.

Estimated CSM mass greater than 1 solar mass.

Abstract

We present photometric and spectroscopic observations of the Type IIn supernova SN 2019zrk (also known as ZTF20aacbyec). The SN shows a $\gtrsim$ 100 day precursor, with a slow rise, followed by a rapid rise to M $\sim -19.2$ in the $r$ and $g$ bands. The post-peak light-curve decline is well fit with an exponential decay with a timescale of $\sim 39$ days, but it shows prominent undulations, with an amplitude of $\sim 1$ 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, $\sim 16,000$ km s$^{-1}$, even in the last spectra. The last spectrum $\sim 110$ days after the main eruption reveals no evidence for advanced nucleosynthesis. From analysis of the spectra and light curves, we estimate the mass-loss rate to be $\sim 4 \times 10^{-2}$ M$_\odot$ yr$^{-1}$ for a CSM velocity of 100 km s$^{-1}$, and a CSM mass of $\gtrsim 1$ M$_\odot$. 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. }