Abstract
Growing evidence suggests that Type Iax supernovae might be the result
of thermonuclear deflagrations of Chandrasekhar-mass white dwarfs in
binary systems. We carry out Monte Carlo radiative transfer simulations
and predict spectropolarimetric features originating from the supernova
explosion and subsequent ejecta interaction with the companion star.
Specifically, we calculate viewing-angle dependent flux and polarisation
spectra for a 3D model simulating the deflagration of a
Chandrasekhar-mass white dwarf and, for a second model, simulating the
ejecta interaction with a main-sequence star. We find that the intrinsic
signal is weakly polarised and only mildly viewing-angle dependent,
owing to the overall spherical symmetry of the explosion and the
depolarising contribution of iron-group elements dominating the ejecta
composition. The interaction with the companion star carves out a cavity
in the ejecta and produces a detectable, but modest signal that is
significant only at relatively blue wavelengths (≲5000 Å). In
particular, increasingly fainter and redder spectra are predicted for
observer orientations further from the cavity, while a modest
polarisation signal P ~ 0.2 per cent is found at blue wavelengths for
orientations 30° and 45° away from the cavity. We find a
reasonable agreement between the interaction model viewed from these
orientations and spectropolarimetric data of SN 2005hk and interpret the
maximum-light polarisation signal seen at blue wavelengths for this
event as a possible signature of the ejecta-companion interaction. We
encourage further polarimetric observations of SNe Iax to test whether
our results can be extended and generalised to the whole SN Iax class.
Original language | English |
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Article number | A179 |
Number of pages | 7 |
Journal | Astronomy & Astrophysics |
Volume | 635 |
DOIs | |
Publication status | Published - 31 Mar 2020 |
Externally published | Yes |
Keywords
- hydrodynamics
- radiative transfer
- polarization
- methods: numerical
- supernovae: general
- supernovae: individual: SN 2005hk