Unveiling SN 2022eyw: A bright member of the Type Iax supernova subclass

Abstract

We present comprehensive photometric and spectroscopic observations of SN 2022eyw, a luminous member of the Type Iax supernova (SN Iax) subclass. SN 2022eyw reached a peak absolute magnitude of Mg = –17.80 ± 0.15 mag and exhibited a rise time of ∼15 days, placing it among the brighter Iax events. The bolometric light curve indicates a synthesized 56Ni mass of 0.11 ± 0.01 M⊙, with an estimated ejecta mass of 0.79 ± 0.09 M⊙ and kinetic energy of 0.19 × 1051 erg. The spectral evolution from −8 to +110 days past maximum reveals features characteristic of bright SNe Iax, including a transition from Fe III to Fe II dominance, moderate expansion velocities, and a lack of strong C II absorption. TARDIS spectral modeling of the early-phase spectra indicates well-mixed ejecta dominated by Fe-group elements. In addition, traces of unburnt carbon are detected, pointing to incomplete burning as expected in pure deflagration models. The late-time spectral evolution shows a blend of permitted and forbidden lines. Comparison with deflagration models suggests that SN 2022eyw originated from a partial deflagration of a Chandrasekhar-mass white dwarf, with explosion properties intermediate between the N3-def and N5-def models. These observations support pure deflagration of a CO white dwarf as a viable explosion mechanism for its luminous members.