Abstract
iPTF14atg, a subluminous peculiar Type Ia supernova (SN Ia) similar to
SN 2002es, is the first SN Ia for which a strong UV flash was observed
in the early-time light curves. This has been interpreted as evidence
for a single-degenerate (SD) progenitor system, where such a signal is
expected from interactions between the SN ejecta and the non-degenerate
companion star. Here, we compare synthetic observables of
multidimensional state-of-the-art explosion models for different
progenitor scenarios to the light curves and spectra of iPTF14atg. From
our models, we have difficulties explaining the spectral evolution of
iPTF14atg within the SD progenitor channel. In contrast, we find that a
violent merger of two carbon-oxygen white dwarfs with 0.9 and 0.76
M⊙, respectively, provides an excellent match to the
spectral evolution of iPTF14atg from 10 d before to several weeks after
maximum light. Our merger model does not naturally explain the initial
UV flash of iPTF14atg. We discuss several possibilities like
interactions of the SN ejecta with the circumstellar medium and surface
radioactivity from an He-ignited merger that may be able to account for
the early UV emission in violent merger models.
Original language | English |
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Pages (from-to) | 4428-4439 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 459 |
Issue number | 4 |
Early online date | 22 Apr 2016 |
DOIs | |
Publication status | Published - 11 Jul 2016 |
Keywords
- hydrodynamics
- nuclear reactions
- nucleosynthesis
- abundances
- radiative transfer
- methods: numerical
- supernovae: individual: iPTF14atg