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

¹ Department of Astronomy, The Oskar Klein Center, Stockholm University, AlbaNova, 10691 Stockholm, Sweden
e-mail: roberto.rampazzo@inaf.it
² Benoziyo Center for Astrophysics, The Weizmann Institute of Science, Rehovot 76100, Israel
³ Department of Physics, The Oskar Klein Center, Stockholm University, AlbaNova, 10691 Stockholm, Sweden
⁴ Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720, USA
⁵ Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
⁶ Cahill Center for Astrophysics, California Institute of Technology, MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125, USA
⁷ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100 Rehovot, Israel
⁸ Miller Institute for Basic Research in Science, 468 Donner Lab, Berkeley, CA 94720, USA

Received: 2 March 2022
Accepted: 6 June 2022

Abstract

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 ≈ −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 ∼39 days, but it shows prominent undulations, with an amplitude of ∼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, ∼16 000 km s⁻¹, even in the last spectra. The last spectrum ∼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 ∼4 × 10⁻² M_⊙ yr⁻¹ for a CSM velocity of 100 km s⁻¹, and a CSM mass of 1 M_⊙. 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.