The Effects of Circumstellar Dust Scattering on the Light Curves and Polarizations of Type Ia Supernovae*

Abstract

Observational signatures of the circumstellar material (CSM) around Type Ia supernovae (SNe Ia) provide a unique perspective on their progenitor systems. The pre-supernova evolution of the SN progenitors may naturally eject CSM in most of the popular scenarios of SN Ia explosions. In this study, we investigate the influence of dust scattering on the light curves and polarizations of SNe Ia. A Monte Carlo method is constructed to numerically solve the process of radiative transfer through the CSM. Three types of geometric distributions of the CSM are considered: spherical shell, axisymmetric disk, and axisymmetric shell. We show that both the distance of the dust from the SN and the geometric distribution of the dust affect the light curve and color evolutions of SN. We found that the geometric location of the hypothetical circumstellar dust may not be reliably constrained based on photometric data alone, even for the best observed cases such as SN 2006X and SN 2014J, due to the degeneracy of CSM parameters. Our model results show that a time sequence of broadband polarimetry with appropriate time coverage from a month to about one year after explosion can provide unambiguous limits on the presence of circumstellar dust around SNe Ia.

Prospects of Searching for Type Ia Supernovae with 2.5-m Wide Field Survey Telescope

“…Furthermore, the thermonuclear ignition of carbon-oxygen WDs is off-center, suggested by the relationship between the early phase velocity gradient of the ejecta and the late-phase velocity shift of emission lines [61]. The late-phase spectroscopic or photometric observations can also diagnose the existence of circumstellar gas around SNe Ia, or the light echos from interstellar or circumstellar dust [17,62,63].…”

“…To date, the physical nature of SNe Ia, however, is still elusive, such as the pathway of WDs acquiring mass [1], the region of thermonuclear ignition [15], and the existence of a surviving companion or the circumstellar material (CSM) [16,17]. One efficient way to reveal these mysteries is to capture the multi-band photometric signals of SNe Ia soon after the explosion.…”

The Fall and Rise of Cosmic Dust in SN 2018evt

“…SNe Ia are characterized by the absence of hydrogen and the presence of strong singly ionized silicon features soon after explosion [13]. Most normal SNe Ia show an environment with no obvious CSM although it has been suggested that the presence of CSM dust could account for their abnormal extinction properties [14,15,16,17,18,19]. Any CSM around SNe Ia would be due to the mass loss from progenitor systems before the SN explosions.…”