Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Modelling a Supernova
Jeroen Ubink, Folkert Nobels, Henry de Vries
Guided by Prof. dr. O. Scholten
Honours FWN Symposium, June 21st 2014
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Contents
1
Introduction
2
Supernova Mechanism
3
Modelling: where to begin
4
Programming and numerical methods
5
Results and outlook
6
Summary
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Introduction: What is a Supernova?
Stellar explosion that briefly
outshines an entire galaxy
Matter expelled at v ≈
c
10
SN 1006 a
a
Retrieved from http://hubblesite.org/newscenter/archive/releases/2005/37/image/a/ on 2
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Research
Supernovae useful as gauging point for observations
Detected ’Superluminous’ Supernova explosions too bright
Include a highly magnetic, neutron star (Magnetar) to boost
luminosity
Goal: model a Magnetar-powered Supernova explosion
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Life of a star
Life of a star: radiative
pressure versus gravity
New reactions and elements
as pressure increases
Pressure vs. gravity in a starb
b
Retrieved from http://cse.ssl.berkeley.edu/bmendez/ay10/2002/notes/pics/bt2lf1402_a.jpg on 23-06-2014
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
End of star life
Fusion process starts to end
when Fe/Ni starts to form
Fusion beyond Fe is energetically unfavorablec
c
Retrieved from http://ec.europa.eu/research/energy/print.cfm?file=/comm/research/energy/fi/fi_bs/article_
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
End of star life
Star starts to shrink as
fusion comes to a halt
Emergency brakes: electronand neutron degeneracy
pressure
Filling of energy levels
creates pressure
Example of energy level fillingd
d
Retrieved from http://linus.chem.ku.edu/genchemlab/1852007/Chemistry_185/Particle%20in%20a%20Box/Particle
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
What happens after the implosion?
Neutron degeneracy pressure keeps the star from imploding
fully
Shockwave of the implosion ’rebounds’ on the core
Matter is blown away at velocities up to v ≈
Modelling a Supernova
c
10
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Modelling: where to begin
Define starting situation model and assumptions
Radial symmetry
Gas composition
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Discretization
Discretization of a
continuous system
Most important
discretization: divide the
star into multiple shells with
different radii
Time needs to be discretized
in time steps
Shell discretizatione
e
Retrieved from http://spiff.rit.edu/classes/phys230/lectures/star_age/star_age.html on 25-6-2014
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Discretization - an example
Continuous function: a(r ) = − Gmr 2encl −
h i
p −pi−1
Discrete: dp
= rii −ri−1
dr
i
Modelling a Supernova
1 dp
ρ dr
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
How to test the code
Use a static, well known solution to test shell behavior
Earth-like atmosphere with fixed or variable temperatures
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Results
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Results and outlook
Expansion not sufficient for
generating good light curves
Improve physics of the
model
Possibly add Magnetar to
luminosity calculations
Modelling a Supernova
Introduction
Supernova Mechanism
Modelling: where to begin
Programming and numerical methods
Results and outlook
Summary
Summary
Supernovae: explosions of ’Burnt-out’ stars
For modelling: make assumptions regarding physics
Descretize equations
Test dynamics on a known solution
Supernova not working properly yet
Modelling a Supernova