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| Paper: |
A Spherical Chandrasekhar-Mass Delayed-Detonation Model for a Normal Type Ia Supernova |
| Volume: |
493, 19th European Workshop on White Dwarfs |
| Page: |
559 |
| Authors: |
Blondin, S.; Dessart, L.; Hillier, D. J. |
| Abstract: |
The most widely-accepted model for Type Ia supernovae (SNe Ia) is the
thermonuclear disruption of a White Dwarf (WD) star in a binary
system, although there is ongoing discussion about the combustion
mode, the progenitor mass, and the nature of the binary
companion. Observational evidence for
diversity in the SN Ia population seems to require multiple
progenitor channels or explosion mechanisms.
In the standard single-degenerate (SD) scenario, the WD grows in mass
through accretion of H-rich or He-rich material from a non-degenerate donor
(e.g., a main-sequence star, a subgiant, a He star, or a red
giant). When the WD is sufficiently close to the Chandrasekhar limit
(∼1.4 M☉), a subsonic deflagration front forms near the WD
center which eventually transitions to a supersonic detonation (the so-called
“delayed-detonation” model) and unbinds the star.
The efficiency of the WD growth in mass remains uncertain, as repeated
nova outbursts during the accretion process result in mass ejection
from the WD surface. Moreover, the lack of observational signatures of
the binary companion has cast some doubts on the SD scenario, and
recent hydrodynamical
simulations have put forward WD-WD mergers
and collisions as viable alternatives.
However, as shown here, the standard Chandrasekhar-mass
delayed-detonation model remains adequate to explain many normal
SNe Ia, in particular those displaying broad Si II 6355 Å lines.
We present non-local-thermodynamic-equilibrium time-dependent
radiative transfer simulations performed with CMFGEN of a spherically-symmetric
delayed-detonation model from a Chandrasekhar-mass WD
progenitor with 0.51 M☉ of 56Ni (Fig. 1 and Table 1), and
confront our results to the observed light curves and spectra of the
normal Type Ia SN 2002bo over the first 100 days of its evolution. With no
fine tuning, the model reproduces well the bolometric (Fig. 2)
and multi-band light curves, the secondary near-infrared maxima
(Fig. 3), and the spectroscopic evolution (Fig. 4),
illustrating the small impact of multi-dimensional processes for this
event.
Mergers or collisions of WD-WD systems should fare as well in
reproducing the observational properties of normal
SNe Ia to compete with the standard SD scenario. |
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