Ay 123 Lecture 11 - Supernovae & Neutron Stars
Timescales for HS Burning
faster and
faster..
Structure of Massive Star at End of HS Burning
Neutrinos Arrive from SN1987A
Hirata et al Phys. Rev. Lettt 58, 1490 (1987)
Neutrino Trapping
Supernova Discoveries
Supernovae Light Curves
II Plateau
Ia
II Linear
Doggett & Branch AJ 90, 2303 (1985)
Supernovae Spectra
Thermonuclear:
Type Ia: Si, no H
Core Collapse:
Type II: H emission
Type Ib: He, weak H
Type Ic: no H, no He
Review: Filippenko,
ARAA 35, 309 (1997)
Origin of `P Cygni’ Profile
P Cygni: luminous blue variable with blue-shifted (absorbing)
outflow against core emission
Delayed Explosions
Decay of Nuclei and SN II light curves
Ni56 t=6.1d
Co56 t=77d
SN1987A: McCray ARAA 31, 175 (1993)
The Ring Around SN1987A
Original FOC image (1990)
Post-repair image
1.66”
IUE observes a brightening in UV emission
lines 413d after SN explosion - pre-SN ejecta
is being illuminated by the explosion.
Resolving the diameter of the ring gives its
size and an absolute distance to the LMC
Panagia et al Ap J 380, L29 (1991)
Cosmological Distances from SN II P
Flux, temperature & expansion velocity during `plateau phase’
Hubble Diagram for SNe IIP
scatter = 0.26 mag
(for Ia scatter~0.20)
Could detect acceleration with present technology (~15 SNIIP)
More effectively probe to high z with JWST/TMT (Nugent et al 2006)
SN Ia Light Curve Shape - Luminosity Correlation
Reduces scatter on `Hubble diagram’
No correction
Correction
Phillips 1993 Ap J 413, L105; Riess et al 1995 Ap J 438, 17
Host Galaxy Dependence of SNe Ia Properties
Ia rate
SFR/mass
Width of light curve
SN Ia rate correlates with specific SFR of host galaxy
Light curve `stretch’ likewise correlates
SN properties depend on mix of stellar population
Sullivan et al Ap J 648, 868 (2006)
Routes to a SNeIa in single degenerate C-O WD systems
(Nomoto et al astro-ph/9907386)
AGB with
C+O core
RG+He
core
WD + MS in
common
envelope
WD + red giant
Wind reduces
rate
Short time delay
Significant time delay
Cosmic Acceleration From SNe Ia
Perlmutter et al 1999
• Light curve corrected peak luminosities give luminosity distance
• Redshifts give cosmic expansion velocities
• SNe Ia are too faint for a given redshift c.f. decelerating models!
Implications of Cosmic Acceleration
Why not ? two puzzles:
• expect =
8GmP4
Perlmutter et al 1999
(10120 larger)
• Why acceleration now?
M  R-3 (matter)
vac = const (vacuum)
Alternative: new physics - “dark energy”:
quintessence: equation of state p = w ;  R-3(1+w)
dynamical scalar field w = w(t)
Deep HST Survey
Riess et al Ap J 659, 98 (2007)
First Year Results from CFHT SNLS
Astier et al A&A 447, 31 (2006)
71 homogenously studied SNe Ia
w = -1.023 ± 0.090
i.e. equivalent to Cosmological
Constant