SN 2020sck: Deflagration in a Carbon-Oxygen White Dwarf

We present optical UBVRI photometry and low-to-medium resolution spectroscopic observations of type Iax supernova SN 2020sck spanning -5.5 days to +67 days from maximum light in the B-band. From the photometric analysis we find Delta m ( B )(15) = 2.03 +/- 0.05 mag and M ( B ) = -17.81 +/- 0.22 mag. Radiation diffusion model fit to the quasi-bolometric light curve indicates 0.13 +/- 0.02 M (circle dot) of Ni-56 and 0.34 M (circle dot) of ejecta are synthesized in the explosion. Comparing the observed quasi-bolometric light curve with the angle-averaged bolometric light curve of a three-dimensional pure deflagration explosion of M (ch) carbon-oxygen white dwarf, we find agreement with a model in which 0.16 M (circle dot) of Ni-56 and 0.37 M (circle dot) of ejecta is formed. By comparing the +1.4 days spectrum of SN 2020sck with synthetic spectrum generated using SYN++, we find absorption features due to C ii, C iii, and O i. These are unburned materials in the explosion and indicate a C-O white dwarf. One-dimensional radiative transfer modeling of the spectra with TARDIS shows higher density in the ejecta near the photosphere and a steep decrease in the outer layers with an ejecta composition dominated mostly by C, O, Si, Fe, and Ni. The star-formation rate of the host galaxy computed from the luminosity of the H alpha (lambda 6563) line is 0.09 M (circle dot) yr(-1), indicating a relatively young stellar environment.

Automated summary

This study presents optical UBVRI photometry and spectroscopic observations of type Iax supernova SN 2020sck. The results indicate the composition and density distribution of the synthesized ejecta in the explosion, as well as the star formation rate of the host galaxy.