Low luminosity Type II supernovae -- IV. SN 2020cxd and SN 2021aai, at the edges of the sub-luminous supernovae class

Understand

Photometric and spectroscopic data for two Low Luminosity Type IIP Supernovae (LL SNe IIP) are presented.

• SN 2020cxd reaches a peak absolute magnitude $M_{r}$ = -13.90 $\pm$ 0.05 mag two days after explosion, subsequently settling on a plateau for $\sim$120 days.
• Through the luminosity of the late light curve tail, we infer a synthesized $^{56}$Ni mass of (1.8$\pm$0.5) $\times$ 10$^{-3}$ M$_{\odot}$.
• During the early evolutionary phases, optical spectra show a blue continuum ($T$ $>$ 8000 K) with broad Balmer lines displaying a P Cygni profile, while at later phases Ca II, Fe II, Sc II and Ba II lines dominate the spectra.