# Presentation: 376471

##       Modeling Type Ia Supernovaefrom ignition, to explosion, to emission

- Daniel Kasen
- UC Santa Cruz

## Supernova Discovery HistoryAsiago Catalog (all supernova types)

- Supernova Discovery HistoryAsiago Catalog (all supernova types)

## Supernova Discovery FutureRough predictions and promises...

- Supernova Discovery FutureRough predictions and promises...

- PanStarrs
- Dark Energy Survey
- JDEM
- Large Synoptic Survey
-      Telescope (LSST)

- Can we use Type Ia SNe as reliable standard candles at the few % level?
*Systematic error*, not statistical error,
- is the issue (e.g., luminosity evolution)

## SN Ia ProgenitorsAccreting white dwarf near the Chandrasekhar limit

- Accretion rate:
- 10-7 Msun / year

- _Issues with the single degenerate scenario_
- Where is the hydrogen?
- How do you make them in old (~10 Gyr) systems?
- What about observed “Super-Chandra” events?
- Could double white dwarf systems be the answer?

## C/O

- boom

## Type Ia Supernova Light Curvespowered by the beta decay: 56Ni     56Co     56Fe

- Type Ia Supernova Light Curvespowered by the beta decay: 56Ni     56Co     56Fe

## Type Ia Width-Luminosity Relationbrighter supernovae have broader light curves

## Type Ia Supernova Spectrum

- 20 days after explosion

## Toy Type Ia  Supernova  Models

- w/ Stan Woosley
- Sergei Blinikov
- Elena Sorokina
- Spherical
- Chandrasekhar mass
- models with
- varied composition

- _Parameters_
- MFe
- MNi
- MSi
- “mixing”

- MFe + MNi + MSi  + Mco = MCH

## 3-dimensional Time-Dependent  Monte Carlo Radiative Transfer

_**SEDONA Code**_
- Expanding atmosphere
- Realistic opacities
- Three-dimensional
- Time-dependent
- Multi-wavelength
- Includes spectropolarization
- Treats radioactive decay
-    and gamma-ray transfer
- Iterative solution for
-      thermal equilibrium
- Non-LTE capability

- Kasen et al 2006 ApJ

## EJECTA

- MODEL

## Broadband Synthetic Light CurvesModel Compared to observations of SN 2001el 

- Kasen (2006) ApJ

- _Parameters_
- MFe = 0.1 Msun
- MNi = 0.6 Msun
- MSi  = 0.4 Msun

- Kasen, ApJ 2006

## Time Evolution of SpectrumRecession of photosphere reveals deeper layers

- Time Evolution of SpectrumRecession of photosphere reveals deeper layers

- Fe

- 56Ni

- Si/S/Ca

- C/O

- Model
- SN1994D

##     Spectroscopic     Time Series

- Day 1 to Day 100

- _Optical_

## Width-Luminosity RelationshipKasen and Woosley, ApJ, 2007 

- Width-Luminosity RelationshipKasen and Woosley, ApJ, 2007

## Supernova Ejecta Opacity blending of millions of line transitions

- _FeIII bound-bound_

## Infrared Secondary Maximum marks the transition from FeIII to FeII

- Kasen (2006) ApJ

- I-Band

## Infrared Secondary Maximum brighter supernovae have later secondary maxima

- Kasen (2006) ApJ

- I-Band

- Vary 56Ni mass
- from 0.35-0.70 Msun

- Kasen (2007)

## Origin of the Width-Luminosity Relationdimmer SN are cooler, and recombine to FeII faster

- B-band

- I-band

## Model Width-Luminosity RelationWoosley, Kasen, Blinnikov, Sorokina, ApJ (2007)

- SN 91T

- SN 99by

- B-band

## Light Curves / Spectra

- free expansion

*(~1-100 days*)
- radioactive decay / radiative transfer

- Type Ia
- supernova
- modeling
- challenge

- ignition

- Presupernova Evolution
- (*~1000-10**9** years*)
- accreting, convective white dwarf

- Explosion
*(~1-100 secs*)
- turbulent nuclear combustion / hydrodynamics

- Observations

## White Dwarf Convection and IgnitionKuhlen, Woosley, and Glaitzmeier (2006)

## White Dwarf Convection (No rotation)3-D calculation, Ma and Woosley

## White Dwarf Convection (With Rotation)3-D calculation, Ma and Woosley

## 3D Deflagration ModelSubsonic turbulent combustion

- 3D Deflagration ModelSubsonic turbulent combustion

- Roepke et al. (2005)

- 2D Deflagration Model

- MNi = 0.2 Msun
- EK   = 0.3 x 1051 ergs

- Roepke, Kasen, Woosley

## DeflagrationToDetonationKhokhlov (1991)Hoeflich (1994)Gamezo et al (2005)

*But how to detonate?*

- Gamezo et al.

## 2D Delayed Detonation

- MNi = 0.5 Msun
- EK   = 1.2 x 1051 ergs

- Roepke, Kasen, Woosley

- The stronger the deflagration phase
-  the more pre-expansion
-  the lower the densities at detonation
-  the less 56Ni produced

- Off-Center Ignition

- University of Chicago
- FLASH Center

## Off-center Detonation

- MNi = 1.0 Msun
- EK   = 1.3 x 1051 ergs

- Roepke, Kasen, Woosley

- An alternative to
- super-chandra SNe?
- Howell et al, 2006
- Hillebrandt, Sim, Roepke 2007

## Spectrum of Off-center Detonationexpansion velocities depend on orientation

- Kasen (2006) ApJ

- I-Band

## Spectroscopic Homogeneity and Diversitymonitoring silicon expansion velocities

- from Leonard et al, ApJ 2006

## Asymmetry and PolarizationObserved SNeIa are polarized at ~0.4 % level

## Asymmetry and PolarizationModel polarization spectrum at maximum lightas seen from different viewing angles 

## The Theoretical Understanding of Type Ia Supernovae

- What are the progenitors?
- How and where does ignition happen?
- How might the deflagration transition into a
- detonation?
- How do the light curves depend upon the
- progenitor and its environment?

- Pressing Questions