SN 2021wvw: A core-collapse supernova at the sub-luminous, slower, and shorter end of Type IIPs

TL;DR

SN 2021wvw is a rare, sub-luminous Type IIP supernova with a short plateau, low velocity, and low nickel mass, providing insights into diverse core-collapse supernovae and their progenitors.

Contribution

This study presents detailed observations and modeling of SN 2021wvw, a unique low-luminosity, short-plateau Type IIP supernova, expanding understanding of supernova diversity and progenitor characteristics.

Findings

SN 2021wvw has a short 75-day plateau and sharp transition to the tail phase.

It has a peak magnitude of -16.1 mag and nickel mass of 0.020 Msol.

Hydrodynamical modeling suggests a low-metallicity, high-mass RSG progenitor with significant fallback.

Abstract

We present detailed multi-band photometric and spectroscopic observations and analysis of a rare core-collapse supernova SN 2021wvw, that includes photometric evolution up to 250 d and spectroscopic coverage up to 100 d post-explosion. A unique event that does not fit well within the general trends observed for Type II-P supernovae, SN 2021wvw shows an intermediate luminosity with a short plateau phase of just about 75 d, followed by a very sharp (~10 d) transition to the tail phase. Even in the velocity space, it lies at a lower velocity compared to a larger Type II sample. The observed peak absolute magnitude is -16.1 mag in r-band, and the nickel mass is well constrained to 0.020(6) Msol. Detailed hydrodynamical modeling using MESA+STELLA suggests a radially compact, low-metallicity, high-mass Red Supergiant progenitor (ZAMS mass=18 Msol), which exploded with ~0.2e51 erg/s leaving an ejecta mass of Mej~5 Msol. Significant late-time fallback during the shock propagation phase is also seen in progenitor+explosion models consistent with the light curve properties. As the faintest short-plateau supernova characterized to date, this event adds to the growing diversity of transitional events between the canonical ~100 d plateau Type IIP and stripped-envelope events.