The Progenitors of Type Ia Supernovae
Single Degenerate
vs.
Double Degenerate C
Chandrasekhar Mass WD
vs. He
Sub-Chandrasekhar Mass WD
Companion
M(0) WD ~ 0.6 - 1.1 MO
MCH ~ 1.4 MO
(1) White Dwarf (Metallicity, Mass(0))
(2) Companion (Metallicity, Age)
SNe Ia (E vs. Spiral; Redshift)
• Diversity • Evolution?
Accreting White Dwarf Models
for Type Ia Supernovae
M
WD
Gravitational ignition
Energy Release T
ρ
Compressional Heating Radiative
∝ M Cooling
(ρ, T) Thermonuclear Explosions ( M )
H M > 10-8 MO yr-1 > M
(1) (2)
10-9
Weak
Novae
H-flashes
Steady H-b
M MWD
(1) H: leaving M.S. H
M2 ~ M2/τKH (~3×10-8M24) He
~ 3×10-8 5×10-7 2×10-6
M2,ms ~ 1M 2M 3M
Super-Soft X-ray Source
M2. Nuclear energy generation rate
5e+08
0.9 0.95 1 1.05
M2 (solar mass)
Carbon Flame
C+O WD O+Ne+Mg WD
C+O O+Ne+Mg
/M Saio & Nomoto (1985, 1998)
A&A, ApJ
Electron Capture in ONeMg WD
• 24Mg(e-,ν)24Na
(e-,ν)24Ne
ρ>4.0×109gcm-3
• →collapse
The Progenitors of Type Ia Supernovae
Single Degenerate (Young pop, DTD, CSM)
vs.
Double Degenerate => ONeMg WD
Chandrasekhar Mass WD
vs.
Sub-Chandrasekhar Mass WD
Companion
M(0) WD ~ 0.6 - 1.1 MO
*MS
*RG
MCH ~ 1.4 MO
(1) White Dwarf (Metallicity, Mass(0))
(2) Companion (Metallicity, Age)
SNe Ia (E vs. Spiral; Redshift)
• Diversity • Evolution?
Ellipticals vs. Spirals
• Ellipticals
– Red Giant Companion
– M(0)WD～1.0-1.1M ; ΔMacc～0.3-0.4M
• Smaller C/O ratio
• Smaller Angular Momentum M(56Ni)↓
• Spirals
– RG & MS Companion
– M(0)WD～0.6-1.1M ; ΔMacc～0.3-0.8M
• Larger C/O ratio
M(56Ni)↑
• Larger Angular Momentum
Evolution with RedShift(Age, Metallicity)
Nova: THEA System (Williams et al. 2008)
H M > 10-8 MO yr-1 > M
(1) (2) Accretion Rate:
10-9
Weak Variable
H-flashes
Steady H-b
M < MCH
H
He
Weak Nova
He-flashes He
C+O
M ≈ MCH
H
Weak He flashes
He s-process elements
C+O CSM
Carbon Strong He flash
center Deflagration Fe-peak elements
Stripping of Companion’s
Mass
Mass Transfer Rate
reduced
Circumstellar Matter
Hachisu, Kato, Nomoto (2008a)
ApJ 679, 1390