Exploding Massive Stars: The Perfect ‘App’ for Computational Physics SESAPS 2003 John M. Blondin...
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Transcript of Exploding Massive Stars: The Perfect ‘App’ for Computational Physics SESAPS 2003 John M. Blondin...
Exploding Massive Stars:
The Perfect ‘App’ for Computational Physics
SESAPS 2003
John M. BlondinNorth Carolina State University
What is a supernova?
A single, new star outshines an entire galaxy for weeks.
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The High-Z Supernova Search
The High-Z Supernova Search
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The Crab Supernova Remnant
This debris is located in the same position as a supernova seen by Chinese astronomers in 1054.
Historical Supernovae
Year Report Status
1006 China, Arab lands, Europe Identified with radio SNR
1054 China, Japan Crab Nebula
1181 China, Japan SNR 3C58
1572 Europe (Tycho Brahe), China Tycho's remnant
1604 Europe (Kepler), Japan, Korea Kepler's remnant
Cassiopeia A
OpticalRadio X-Ray
What are we looking at?
•Brightness & distance => 10 billion Suns
•Doppler shifts => expansion at 1000 km/s
•X-Ray emission => few solar masses
An expanding blastwave with 1051 ergs
Where did all that energy come from?
Type Ia - stellar-sized nuclear bomb
Type II - gravitational collapse of a massive star
SN1987A confirmed the basic supernova theory
•A star disappeared! Supernovae do result from the death of a massive star.
•Neutrinos were detected (2002 Nobel Prize), confirming formation of neutron star in the core.
What is left to learn?
• How do they explode?!
• What is the neutrino signature?
• Do they produce gravitational waves?
A Brief History of Supernova Theory
• 1957 Burbidge, Burbidge, Fowler, and Hoyle
• 1966 Colgate and White
• 1985 Bethe and Wilson
• 1992 Herant, Benz, and Colgate
Thermonuclear runaway in envelope
Neutrino-Driven prompt explosion
Shock reheating via neutrino energy deposition
Convective instability above neutrino-sphere
Need Boltzmann SolutionNeed Angular DistributionNeed SpectrumNeed Neutrino Distribution
Fluid Instabilities Rotation Magnetic Fields
6D RMHD Problem!6D RMHD Problem!Need these to few percent accuracy!
http://www.phy.ornl.gov/tsi/TeraScale Supernova InitiativeTeraScale Supernova Initiative
10 Institution, 17 Investigator, ~ 40 Person, Interdisciplinary Effort ascertain the core collapse supernova mechanism(s)understand supernova phenomenology
e.g.: (1) element synthesis, (2) neutrino, gravitational wave, and gamma ray signatures provide theoretical foundation in support of OS experimental facilities (RHIC, SNO, RIA, NUSL)develop enabling technologies of relevance to many applications
e.g. 3D, multifrequency, precision radiation transportserve as testbed for development and integration of technologies in simulation “pipeline”
e.g. data management, networking, data analysis, and visualization
Explosions ofExplosions ofMassive StarsMassive Stars Relevance:Relevance:
Element ProductionElement ProductionCosmic LaboratoriesCosmic LaboratoriesDriving ApplicationDriving Application
With ISIC and other collaborators:With ISIC and other collaborators:~120 people from 24 institutions involved.~120 people from 24 institutions involved.
What will it take? Tera/Peta-Scale 3D, General Relativistic, Radiation Magnetohydrodynamics State of the Art Nuclear and Weak Interaction Physics
“Infrastructure” Needs: Applied Mathematics Tera- and Peta-Scale Sparse Linear Systems of Equations
“Infrastructure” Needs: Data Management/Visualization 1-10 Tb/Variable/Simulation!
Manage? Analyze? Render?
“Infrastructure” Needs: NetworkingHow can a nationally distributed team work together effectively?
Messer et al. (2002) Liebendoerfer et al. (2002)
No Explosions!No Explosions!New Microphysics?New Microphysics?
High-Density Stellar Core ThermodynamicsHigh-Density Stellar Core ThermodynamicsNeutrino-Matter InteractionsNeutrino-Matter Interactions
New Macrophysics? (2D/3D Models)New Macrophysics? (2D/3D Models)Fluid Instabilities, Rotation, Magnetic FieldsFluid Instabilities, Rotation, Magnetic Fields
TSI will explore both!
No 2D/3D supernova models with realistic neutrino transport exist!
One Dimension is Too Simple
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SAS Solution is Stable in One Dimension
time
radius
Pressure perturbation
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SASI: l=1 mode is overstable
The obliquity of the accretion shock deflects the radial in-flow
Spherical shock
Radial in-fall
Shocknormal
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Challenges in Data Management
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First steps toward understanding the role of magnetic fields…
What impact will they have on the collapse and postbounce dynamics?How much do they factor into generating the explosion?
How much will they be amplified, and how? Wrapping Dynamo Magnetorotational Instability (Balbus and Hawley 1991)
Akiyama et al. (2002)
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Asif ud-Doula (see poster)SASI + Dipole Field
How did this happen?!