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 gradient in H and He erased by mixing processes or does it survive? Changes the entire stellar structure and whether it burns helium as a blue star or a red star.

note models “b” (with B-fields) and “e” (without) Heger, Woosley, & Spruit, in prep. for ApJ Spruit, (2001), A&A, 381, red supergiants at death. Pulsar periods 3 to 15 ms

Burrows, Hayes, and Fryxell (1995) Mezzacappa et a l (1998) The current paradigm for supernova explosion powered by neutrino energy deposition gives 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 1970 Wheeler et al 2002 Fryer and Heger 2000

First three-dimensional calculation of a core-collapse 15 solar mass supernova. This figure shows the iso-velocity contours (1000 km/s) 60 ms after core bounce in a collapsing massive star. Calculated by Fryer and Warren at LANL using SPH (300,000 particles). Resolution is poor and the neutrinos were treated artificially (trapped or freely streaming, no gray region), but such calculations will be used to guide our further code development. The box is 1000 km across. 300,000 particles 1.15 Msun remnant 2.9 foe 1,000,000 “ 1.15 “ 2.8 foe – 600,000 particles in convection zone 3,000,000 “ 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 runs into the massive, but low density hydrogen envelope, the shock at its boundary decelerates. The deceleration is in opposition to the radially decreasing density gradient of the supernova. Rayleigh-Taylor instability occurs. The calculation at the right (Herant and Woosley, ApJ, 1995) shows a 60 degree wedge of a 15 solar mass supernova modeled using SPH and 20,000 particles. At 9 hours and 36 hours, the growth of the non-linear RT instability is apparent. Red is hydrogen, yellow is helium, green is oxygen, and blue is iron. Radius is in solar radii. Mixing

with FLASH

Fall back

Fall back absorbs all the 56 Ni light curves without mixing - will be recalculated 30 models Light curves

Nuclear Reaction Data

25 Solar Mass Supernova 15 Solar Mass Supernova T he figures at the right show the first results of nucleosynthesis calculations in realistic (albeit 1D) models for two supernovae modelled from the main sequence through explosion carrying a network of 2000 isotopes in each of 1000 zones. A (very sparse) matrix of 2000 x 2000 was inverted approximately 8 million times for 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 Chandrasekhar Mass white dwarf as its center runs away – following about a century of convection. Vertical bars denote convective regions

Convection for 100 years, then formation of a thin flame sheet. T radius 0 Note that at: 7 x 10 8 K the burning time and convection time become equal. Can’t maintain adiabatic gradient anymore 1.1 x 10 9 K, burning goes faster than sound could go a pressure scale height Burning becomes localized

Timmes and Woosley, (1992), ApJ, 396, 649 Laminar Flame Speed km/s cm

Speculation How many points and when and where each ignites may have dramatic consequences for the supernova (origin of diversity?)

"Sharp-Wheeler Model" g Model OK, but deficient in Si, S, Ar, Ca A simple toy model...

Igniting the star at a single point off center gives very different results than igniting precisely at the center or in a spherical volume. This "single point ignition" model did not produce a supernova (pulsation would have ensued)

Ignition at 5 points did produce a successful supernova with 0.65 solar masses of burned material, 0.5 solar masses of which was 56 Ni. Note - this was a 2D calculation.

Reinecke et al. (2002)

An idealized model Assume a starting mass of 1.38 solar masses, a central density of 2 x 10 9 g cm -3 and a C/O ratio of 1::2 For a given starting density, the final composition (three variables, plus mixing) then defines the model.

X-Ray Bursts Zingale Cumming Woosley et al.

Lorentz factor Density GRBs