This study uses 3D supernova simulations to examine nucleosynthesis yields under different explosion conditions. A symmetric explosion produces high 26Al abundances throughout the ejecta. An off-axis asymmetric explosion yields more 44Ti and 56Ni in the inner ejecta. The most asymmetric case, with a compact object and interstellar medium, produces the least 26Al but most 44Ti, concentrated in outer convective streams. Production amounts of various isotopes are reported.

1. Introduction
We present here three case studies of the
effects of asymmetries on the yield of 26
Aluminum, 44 Titanium , and 56 Nickel ,
with attendant plots of the Sulfur to Silicon
ratio which is commonly used as a
diagnostic.
Observations as well as previous modelling
efforts have identified Rayleigh-Taylor
Instability features which form in the
supernova remnant (1) and can go on to
interact with protoplanetary discs, enriching
them in short lived radionuclides and other
materials (2,3). However the production of
these same isotopes of interest was found
to vary depending on progenitor conditions
and asymmetries in the explosion(4).
Materials and methods
The supernova progenitor in each case was
evolved using the TYCHO code (5) to the
point of core collapse before having the
earliest explosion phase solved in 1
Dimension. This was then mapped into
SNSPH (6) and evolved in 3D before being
re-processed by Burn (7) to give the final
nucleosynthesis yields. The outputs from
Burn were accessed using a custom C
application and visualized using
ParaView(8).
The first case considered was fully
symmetric, while the second considered the
same progenitor with an off-axis high
velocity region imposed during the initial
explosion phase. The third was an
extremely asymmetrical explosion with the
interstellar medium present in the model as
well as a central compact object.
Acknowledgments
I would like to thank Colin Purrington for
the excellent poster design advice,
Starbucks for the motivation to try
raw-reading SDF files, and not least of all Dr.
Young for helping clear up confusion. Thank
also go to the ASU High-performance
computing group, A2C2, for the use of their
excellent computing facilities.
Results Conclusions
In the symmetric case 26Al was present at
high abundances through the base of the
Rayleigh-Taylor features and, surprisingly,
the interior of the main ejecta shell. The
26Al-rich areas in the RT layer had the
characteristic S/SI ratio of 0.06, while the
inner areas typically tended higher (~0.5 &
higher). 56Ni was at its highest abundance
in the area just behind the density jump at
the base of the RT fingers, but still quite
abundant inwards, while the 44Ti was most
apparent just a bit further inward of the
56Ni area, indicating a transition to
alpha-rich freeze out.
The asymmetric case follows similar
distribution patterns but shows marked
differences in the form of the denser, inner
ejecta area not apparent in the symmetric
case. The S/Si ratio is approx. 0.5 in the 26Al
bearing areas at the base of the RT layer
while the deeper area has a much higher
S/Si of ~2. This same deep ejecta region
shows marked elevation of 44Ti and 56Ni,
again with 44Ti concentrated inside of the
peak 56Ni mass fractions. Neither the 44Ti
nor the 56Ni is especially abundant at the
base of the RT layer, but is present all
through the inner cavity clumps generated
by Ni-decay heated bubbles.
The most complicated case had the least
26Al but the most 44Ti, showing only a
small amount of Al around the inner
boundary of the RT region, but significant
44Ti and 56Ni throughout the outer areas of
the convective streams in the inner cavity.
The S/Si diagnostic for 26Al holds up, with a
0.06 ratio in the areas still containing 26Al.
Final production amounts of several
isotopes of interest in Msol follows in the
table below. The asymmetric case is more
efficient at ejecting outer shells of the
progenitor, consistent with the introduction
of the velocity outside the base of the
Si-burning shell. The presence of the
compact object causes significantly more
fallback, and the fluid flows generated even
affect outer layers.
Jack M. Sexton¹, Patrick A. Young¹, Carola I. Ellinger², Christopher L. Fryer³, & Gabriel Rockefeller³
(1) Arizona State University, Phoenix, AZ; (2) University of Texas, Arlington, TX; (3) Los Alamos National Laboratories, Los Alamos, NM
Literature cited
(1) Ellinger, Young, Fryer, & Rockefeller. 2012. A Case Study of Small Scale Structure Formation in 3D Supernova Simulations The Astrophysical Journal,
755:160.
(2) Ouellette, Desch, & Hester. 2007. Interaction of Supernova Ejecta with Nearby Protoplanetary Disks. The Astrophysical Journal, 662:1268-1281.
(3) Wadwha et al. 2007. From Dust to Planetesimals: Implications for the Solar Protoplanetary Disk from Short-lived Radionuclides. Protostars and
Planets V, p.835-848
(4) Young, Ellinger, Arnett, Fryer, & Rockefeller. 2009. Finding tracers for supernova produced 26Al. The Astrophysical Journal, 699:938–947.
(5) Young and Arnett. 2005. Observational Tests and Predictive Stellar Evolution. II. Nonstandard Models. The Astrophysical Journal, 618:908-918.
(6) Fryer, Rockefeller, & Warren. 2006. SNSPH: A Parallel Three-dimensional Smoothed Particle Radiation Hydrodynamics Code. The Astrophysical
Journal, 643:292-305.
(7) Young and Fryer. 2007. Uncertainties in Supernova Yields I: 1D Explosions. The Astrophysical Journal, 664:1033-1044. Henderson, 2007.
(8) ParaView Guide, A Parallel Visualization Application. Kitware Inc., 2007
A case study of nucleosynthesis in multi-dimensional supernova simulations
26Al mass fraction (left) and the Sulfur/Silicon ratio
(right) superimposed on a monochrome density map of
a slice through the zy plane.
Symmetric Case
The 44Ti (left) and 56Ni (right) mass fraction
superimposed on a monochrome density map of a
slice through the zy plane.
26Al mass fraction (left) and the Sulfur/Silicon ratio
(right) superimposed on a monochrome density map of
a slice through the zx plane.
Asymmetric Case (off-axis High-Velocity Feature)
The 44Ti (left) and 56Ni (right) mass fraction
superimposed on a monochrome density map of a
slice through the zx plane.
Asymmetric, off-center explosion with the effects of
a Compact Central Object and the Interstellar Medium
26Al mass fraction (left) and the Sulfur/Silicon ratio
(right) superimposed on a monochrome density map of
a slice through the zy plane.
The 44Ti (left) and 56Ni (right) mass fraction
superimposed on a monochrome density map of a
slice through the zy plane.
Symmetric Asymmetric CCO + ISM
C 5.80E-05 4.30E-03 1.56E-03
O 6.67E-02 3.88E-01 1.85E-01
26Al 1.15E-06 1.20E-06 1.22E-07
Si 6.17E-02 6.00E-02 2.25E-02
P 3.57E-05 4.39E-05 5.78E-05
S 3.93E-02 3.79E-02 1.40E-02
Ca 6.36E-03 5.95E-03 2.89E-03
44Ti 2.81E-04 2.72E-04 4.17E-04
54Fe 1.63E-03 1.45E-03 8.18E-04
56Fe 7.54E-05 2.74E-04 9.41E-05
56Ni 1.06E-01 1.05E-01 6.37E-02