SN2024abfl: A Low-Luminosity Type IIP Supernova at the Low-Mass End of Core Collapse

TL;DR

SN 2024abfl is an extremely faint, low-luminosity Type IIP supernova with an unusually long plateau and very low expansion velocities, suggesting a low-mass core-collapse origin.

Contribution

This study reports the discovery and detailed analysis of one of the faintest Type IIP supernovae, highlighting its unique spectral and photometric properties and implications for low-mass progenitors.

Findings

SN 2024abfl has a plateau luminosity of ~10^41 erg/s.

It exhibits exceptionally low expansion velocities (~1200 km/s at 50 days).

The estimated nickel mass is very low (~0.002-0.004 M_sun).

Abstract

We present optical photometric and spectroscopic observations of the low-luminosity (LL) Type IIP supernova SN\,2024abfl. The distance to its host galaxy is highly uncertain, with independent estimates of $9.5^{+2.3}_{-2.4}$ Mpc and $15.0^{+8.9}_{-1.9}$ Mpc. Even adopting the larger distance, the inferred plateau luminosity is only $\sim 10^{41}\rm erg\,s^{-1}$, placing SN 2024abfl at the extreme faint end of SNe IIP population. Its light curve exhibits a long-lasting plateau of approximately 110 days. The spectra show exceptionally low expansion velocities, with the \FeII\, velocity of $\sim1200\,\rm km\,s^{-1}$ at 50 days after the explosion, significantly lower than the typical values of $\sim2000-5500\,\rm km\,s^{-1}$ observed in SNe IIP, placing SN\,2024abfl among the slowest-expanding LL SNe IIP. Bolometric modeling yields a synthesized $^{56}$Ni mass of $\sim0.002-0.004\,\rm M_\odot$, though this estimate remains subject to significant uncertainty owing to the poorly constrained distance. Considering the plateau color and duration, the magnitude drop from plateau to tail, and the progenitor luminosity, we favor a low-mass core-collapse origin for SN\,2024abfl.