Massive star evolution

convection semiconvection overshoot

angular momentum transport with and without B-field torques

nucleosynthesis

presupernova models

Supernovae Type II

Core collapse Neutrino transport B-fields and rotation Mass dependence Equation of state

Mixing and fall back

Nucleosynthesis

Light curves

Spectra

Supernovae Type Ia

Ignition – the last 100 seconds

Flame physics and instabilities

Flame propagation – 3D with attendant turbulence and instabilities

Nucleosynthesis Light curves

Spectra

Transients

X-ray bursts – large reaction networks

novae – dredge up and mixing

gamma-ray bursts progenitors central engine relativistic jet propagation

Nuclear Reaction Data Base

Tabulations of experimental rates

Calculation of theoretical strong, weak, electromagnetic, and neutrino rates

Fitting and extrapolation

Archiving and disemination

Michael Kuhlen – rotating 15 solar mass star burning hydrogen

Rogers, Glatzmaier, and Woosley (2002)

Semiconvection:

E.g., following hydrogen core burning, is the gradientin H and He erased by mixing processes or does it survive?

Changes the entire stellar structure and whether it burns helium as a blue staror a red star.

note models “b” (withB-fields) and “e” (without)

Heger, Woosley, & Spruit,in prep. for ApJ

Spruit, (2001), A&A, 381, 923

- red supergiants at death. Pulsar periods 3 to 15 ms

Burrows, Hayes,and Fryxell (1995)

Mezzacappa et a l (1998)

The current paradigm forsupernova explosion poweredby neutrino energy depositiongives ambiguous results.

Rotation could alter this by

• Providing extra energy input

• Creating ultrastrong B fields and jets

• Changing the convective flow pattern

Ostriker and Gunn 1971

LeBlanc and Wilson 1970Wheeler et al 2002

Fryer and Heger 2000

First three-dimensional calculation of a core-collapse15 solar mass supernova.

This figure shows the iso-velocitycontours (1000 km/s) 60 ms aftercore bounce in a collapsing massivestar. Calculated by Fryer and Warrenat LANL using SPH (300,000 particles).

Resolution is poor and the neutrinoswere treated artificially (trapped orfreely streaming, no gray region), butsuch calculations will be used toguide our further code development.

The box is 1000 km across.

300,000 particles 1.15 Msun remnant 2.9 foe1,000,000 “ 1.15 “ 2.8 foe – 600,000 particles in convection zone3,000,000 “ in progress

Or do we simply not have the correct equation of state?

Or do we need to do the multi-D neutrino transport better?

Or is new physics needed (flavor mixing?)?

As the expanding helium core runsinto the massive, but low densityhydrogen envelope, the shock at itsboundary decelerates. The decelerationis in opposition to the radially decreasingdensity gradient of the supernova.

Rayleigh-Taylor instability occurs.

The calculation at the right (Herant andWoosley, ApJ, 1995) shows a 60 degree wedge of a 15 solar mass supernova modeledusing SPH and 20,000 particles. At 9 hours and 36 hours, the growth of thenon-linear RT instability is apparent.

Red is hydrogen, yellow is helium, greenis oxygen, and blue is iron. Radius is insolar radii.

Mixing

with FLASH

Fall back

Fall back absorbs all the 56Ni

light curves without mixing - will be recalculated

30 models

Light curves

Nuclear Reaction Data

25 Solar Mass Supernova

15 Solar Mass Supernova

The figures at the right showthe first results of nucleosynthesiscalculations in realistic (albeit1D) models for two supernovaemodelled from the main sequencethrough explosion carrying a network of 2000 isotopes ineach of 1000 zones.

A (very sparse) matrix of 2000 x 2000 was invertedapproximately 8 million timesfor each star studied.

The plots show the log of the final abundances compared to their abundance in the sun.

Nucleosynthesis

The ignition conditions depend weakly on the accretion rate.For lower accretion rates the ignition density is higher. Because of the difficulty with neutron-rich nucleosynthesis,lower ignition densities (high accretion rates) are favored.

*Ignition when nuclear energy generation by (highly screened) carbon fusion balances cooling by neutrino emission.

Type Ia Supernovae – White dwarf accretion

Conditions in a ChandrasekharMass white dwarf as its center runs away – following about a century of convection.

Vertical bars denoteconvective regions

Convection for 100 years, then formation of a thin flame sheet.

T

radius0

Note that at:

7 x 108 K the burning time and convection time become equal. Can’t maintain adiabatic gradient anymore

1.1 x 109 K, burning goes faster than sound could go a pressure scale height

Burning becomes localized

26TSnuc

Timmes and Woosley, (1992), ApJ, 396, 649

2/1

condv

nucS

c

Laminar Flame Speed

km/s

cm

km/s000,10sound c

Speculation

How many points and when and whereeach ignites may have dramatic consequencesfor the supernova (origin of diversity?)

2/L km 200 r P

"Sharp-Wheeler Model"

g

Model OK, but deficient in Si, S, Ar, Ca

2SW

2SW

1.0v

05.0r

tg

tg

eff

eff

A simple toy model ...

Igniting the star at a single point off center gives very different results than ignitingprecisely at the center orin a spherical volume.

This "single point ignition"model did not produce a supernova (pulsation would have ensued)

Ignition at 5 pointsdid produce a successfulsupernova with 0.65 solar masses of burnedmaterial, 0.5 solar masses of which was56Ni.

Note - this was a 2D calculation.

Reinecke et al. (2002)

An idealized model

Assume a starting mass of1.38 solar masses, a centraldensity of 2 x 109 g cm-3

and a C/O ratio of 1::2

For a given starting density, the final composition (threevariables, plus mixing) then defines the model.

X-Ray Bursts

ZingaleCummingWoosley et al.

Lorentz factor DensityGRBs