A Three-Dimensional Deflagration Model for Type Ia Supernovae Compared with Observationsстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:A simulation of the thermonuclear explosion of a Chandrasekhar-mass C+O
white dwarf, the most popular scenario of a Type Ia supernova (SN Ia),
is presented. The underlying modeling is pursued in a self-consistent
way, treating the combustion wave as a turbulent deflagration using well
tested methods developed for laboratory combustion and based on the
concept of ``large-eddy simulations'' (LESs). Such consistency requires
to capture the onset of the turbulent cascade on resolved scales. This
is achieved by computing the dynamical evolution on a 1024$^{3}$
moving grid, which resulted in the best-resolved three-dimensional SN Ia
simulation carried out thus far, reaching the limits of what can be done
on present supercomputers. Consequently, the model has no free
parameters other than the initial conditions at the onset of the
explosion, and therefore it has considerable predictive power. Our main
objective is to determine to which extent such a simulation can account
for the observations of normal SNe Ia. Guided by previous simulations
with less resolution and a less sophisticated flame model, initial
conditions were chosen that yield a reasonably strong explosion and a
sufficient amount of radioactive nickel for a bright display. We show
that observables are indeed matched to a reasonable degree. In
particular, good agreement is found with the light curves of normal SNe
Ia. Moreover, the model reproduces the general features of the abundance
stratification as inferred from the analysis of spectra. This indicates
that it captures the main features of the explosion mechanism of SNe Ia.
However, we also show that even a seemingly best-choice pure
deflagration model has shortcomings that indicate the need for a
different mode of nuclear burning at late times, perhaps the transition
to a detonation at low density.