Paper

Unravelling the asphericities in the explosion and multi-faceted circumstellar matter of SN 2023ixf

Kawabata, M, Kumar, A, Singh, Avinash, Kumar, B, Nakaoka, T, Anche, R M, Raj, A, Watanabe, A, Tanaka, M, Bisht, M S, Sahu, D K, Chakrabarti, S K, Imazawa, R, Smith, P, Sakagami, Y, Bhalerao, V, Nagayama, T, Maeda, K, Fujii, M, Taguchi, K, Malkan, B K, Moriya, T J, Gangopadhyay, A, Swain, V, Teja, R S, Agnihotri, V K, Belwal, K, Kawabata, K S, Bisht, D, Matsumoto, K, Anupama, G C, Kumar, R, Sano, Y, Hamada, T, Yamanaka, M, Tominaga, N

2024

Overview

We present a detailed investigation of photometric, spectroscopic, and polarimetric observations of the Type II SN 2023ixf. Earlier studies have provided compelling evidence for a delayed shock breakout from a confined dense circumstellar matter (CSM) enveloping the progenitor star. The temporal evolution of polarization in SN~2023ixf revealed three distinct peaks in polarization evolution at 1.4 d, 6.4 d, and 79.2 d, indicating an asymmetric dense CSM, an aspherical shock front and clumpiness in the low-density extended CSM, and an aspherical inner ejecta/He-core. SN 2023ixf displayed two dominant axes, one along the CSM-outer ejecta and the other along the inner ejecta/He-core, showcasing the independent origin of asymmetry in the early and late evolution. The argument for an aspherical shock front is further strengthened by the presence of a high-velocity broad absorption feature in the blue wing of the Balmer features in addition to the P-Cygni absorption post 16 d. Hydrodynamical light curve modeling indicated a progenitor of 10 solar mass with a radius of 470 solar radii and explosion energy of 2e51 erg, along with 0.06 solar mass of 56-Ni, though these properties are not unique due to modeling degeneracies. The modeling also indicated a two-zone CSM: a confined dense CSM extending up to 5e14 cm, with a mass-loss rate of 1e-2 solar mass per year, and an extended CSM spanning from 5e14 cm to at least 1e16cm with a mass-loss rate of 1e-4 solar mass per year, both assuming a wind-velocity of 10 km/s. The early nebular phase observations display an axisymmetric line profile of [OI], red-ward attenuation of the emission of Halpha post 125 days, and flattening in the Ks-band, marking the onset of dust formation.

• Publisher: Cornell University Library, arXiv.org
• Subject: Absorption / Asymmetry / Ejecta / Evolution / Light curve / Modelling / Polarization / Stellar envelopes