Evolution and Final Fates ofAccreting White Dwarfs

Ken Nomoto(Kavli IPMU / U. Tokyo)

AD 1572
Korean & Chinese
Record“Guest Staras bright as Venus”（Sonjo Sujong Sillok: Korea)

AD 1572
Tycho Brahe’sSupernova

Stella Nova
(Tycho Brahe 1573)“Astronomie Populaire”
by Camille Flammarion (Paris, 1884)

Remnant of Tycho’s Supernova
Green Yellow
Blue X-ray (Hotgas with millionsof degree)
RedInfrared(Circumstellar/Synthesized dust)(Image: MPIA)

WhiteOptical(Foreground/background stars)

Light Echo of SN 1572 (Tycho)

Echo: Oort, Zwicky, ,,Rest+, Krause+

(SUBARU 2008)

Spectrum ofEcho(Krause, Tanaka, Usuda, Hattori, Goto, Nomoto 2008 Nature)

Iron

SulfurSiliconMagnesium

Calcium
Wavelength (Angstrom)

SpectraBright SN Ia

Normal SN Ia

Faint SN Ia

High Velocity Ca Feature

8

The Progenitors of Type Ia Supernovae ??
Single Degenerate(SD)vs.
Double Degenerate(DD)Chandrasekhar Mass WD
vs.
Sub-Chandrasekhar Mass WDCHe
Companion

Thermonuclear Explosions of White Dwarfs!!

SN Ia: PTF11kx(Dilday et al. 2012)

PTF11kx: Symbiotic Recurrent Nova
RG wind + Recurrent nova ejecta(Dilday et al. 2012)（P~ 10 yrs)

SD (RG+WD)

SN Ia : No Companion Star ?

SNR Tycho（Kerzendorf+ 09)(see, however, RuizLapuente+ 04)

SNR 0509-67.5 in LMC（Shaefer & Pagnotta 12)

SN 2011fein M101
（Li+ 11)

DD ? 

DD, SD  Sub-Ch, Chandra
surface burningc (g cm-3) ~106
DDSD

 sub-Ch
107-8

C-detonation ?  C-det
steady C-burning? no ignition ?
He flashes ?
He detonation ?

 C-det

Chandra109-10

ONeMg WDC-deflag
C-deflagDouble Degenerates (1.1 + 0.9 M)SPH Simulations ofC+O WD Merging
example:N = 4 x 106(Nakasato+ 12)

WD Merging (1.0+0.7)
Tmax

Carbon detonation?
(Pakmor+ 09, 11)

Carbon burning?

(Nakasato+ 11)

Double Degenerate Scenario
Is C-detonation (or He detonation)
ignited near the surface ?
If yes, central C-detonation (Pakmor+ 09, 11)M(eff) ~ M(primary WD) ~ 0.9 – 1.1 Mc ~107 - 8 g cm-3  “sub-Chandra”

If not,  ~ steady state

WD Merging (1.0+0.7)
Carbon detonation?

TmaxCarbon burning?

(Nakasato+ 11)

Double Degenerate Scenario• If Tmax < 6 x 108 K (~ surface) C+C rate < Neutrino cooling rate

 no surface C-ignition (Yoon+2007)

 central C-ignition (accretion rate?)(“Chandra” or “super-Chandra”)• If Tmax > 6 x 108 K (~ surface) C+C rate > Neutrino cooling rate

 surface C-Ignition ( inward) ONeMg WD

WD Merging: Tmax (M1, M2)

Carbon Ignition
Neutrino Cooling(Nakasato + 2010)

Carbon Flame
C+O WD  O+Ne+Mg WD
C+O

O+Ne+Mg/ M

Saio & Nomoto (1985, 1998)(Saio & Nomoto)
A&A, ApJElectron Capture in ONeMg WD• 24Mg(e-,n)24Na(e-,n)24Ne
 >4.0×109gcm-3• →collapse

Single Degenerate Scenario(1) Compressional Heating
M
WD
Gravitational
Energy Release

TignitionCompressional Heating M(, T)

Thermonuclear Explosions ( M )RadiativeCooling(2) Nuclear Burning
H
(2)

(1)
Steady H-b

M > 10-8 MO yr-1 > M
Weak
H-flashes

10-9Novae

M < MCHHHeHHe

Weak
He-flashes

HeM  MCH

C+OCarbon
Deflagration

He-DetonationC+O

centerHydrogen Burning in Accreting WDAccretion
Rate

Nomoto (1982)

White Dwarf Mass(3) White Dwarf Wind(Hachisu, Kato, & Nomoto 1996)

Stripping of Companion’sMass
 Mass Transfer Rate
reduced Massive (young)Companion  SN Ia
Circumstellar Matter10-100 km/S
Hachisu, Kato, Nomoto (2008a)
ApJ 679, 1390)

Candidate Progenitor Systems
for Carbon Ignitors

Hachisu, Kato, Nomoto
Lee, van den Heuvel
Han, Podsiadlowski

410-8 < M (MO yr-1) < 2 10-6
M2. > MWDHCompanion(1) H: leaving M.S.
M2 ~ M2/KH (~3×10-8M24)

He~ 3×10-8 5×10-7 2×10-6
M2,ms ~ 1M

2M

~8M

M2. <(2) H: sub giant, red giant
M2H-shell b.

~ M2/nuclear~ 10-8 ~ 10-6 M/yrHe
0.9 – 2 MMWD

SN Ia Progenitor System(MS, RG)

Recurrent Nova

C-ig: M=1.38 M

Single Degenerate ScenarioM(wd, 0) + M2,0 : P0 (initial orbital period) M(wd, final) [~ 1.38 M ] + M2(final)(1) Compressional Heating (M)(2) H & He Burning(3) Radiation-driven WD Winds(4) Steady Hydrogen Burning(5) Recurrent Novae
 Central Ignition of Carbon Burning

Mass Transfer in a SD system(T. Matsuda)

Evolution of Rotating White Dwarfs(Uniform rotation)
AngularMomentum

M(wd)(e.g., Ostriker, Pacynski, Narayan, Hachisu, Piersanti, Yoon, Saio)

Structure of Rotating WDs
Uniform Rotation
M=1.48 M, J=4.63
Rotation Period = 2.3sec
ρc=2.0e9 (Ignition)
q=0.66(Uenishi, Nomoto, Hachisu 03)

Differential Rotation
M=2.03 Mρc=2.0e9 (Ignition)(Yoon, Langer 05)

Uenishi et al.

SD Scenario for Rotating WDs(Spin-up, Spin-down scenario: Justham 11, Di Stehano+ 11, HKN 12)

M(wd, 0) + M2 (P_0) Accretion  Spin-Up of WD (uniform rotation)
Accretion continues beyond M(wd) = 1.4 M
(1) M(wd, final) = 1.5 M (prompt C-ignition)(2) M(wd, final) = 1.4 - 1.5 M (no C-ignition)
dM/dt < 1 x 10-7 M y-1
 strong Nova outbursts : mass ejection
 M(wd) does not increaseSNe Ia from Uniformly Rotating WDs(1) Mwd, final/M = 1.5 (~ 55 %) :Prompt Carbon-Ignition( e.g., PTF11kx )(2) Mwd, final/M = 1.4 - 1.5 (~ 45 %)Spin-down: angular momentum loss
(magnetic wind,,,,,,,)
 Delayed Carbon-Ignition

Uniformly Rotating WDs:
Prompt vs. Delayed Carbon-Ignition

Delayed C-ig

Prompt C-ig

Prompt C-ig
Delayed C-ig

Mass Distribution of Rotating WDs

Prompt C-ignition(uniformC-ignition
rotation)(differential rotation)
Delayed C-ig
(Spin down)Companions of Rotating WDs
M2 continues to decrease by mass transfer(~1 x 10-8 M y-1) during the spin-down time.
(1) RG  He WD by losing H-envelope(2) MS  low mass MS (M2 < 1 M), or He WD by losing H-envelope
Companions become low mass, compact stars:
 missing companions
Circumstellar matter : dispersed.

Single Degenerate Scenario
Rotating White Dwarfs
 Prompt & Delayed Carbon Ignition

 Spin-up, Spin-down scenario can solve
the missing companion problem.
- mechanism & timescale of spin-down(e.g., Ilkov & Soker 11)

Nucleosynthesis in Chandrasekhar Mass Models
56Ni58Ni

56Fe

Carbon deflagration at
c > 109 g cm-3
 NSE & Electron Capture
 lower Ye (neutron-rich)
58Ni, 56Fer

Late time spectra:Ni, Fe
Nuclear Statistical
Equilibrium (NSE: Ye)Chandrasekhar Mass Models
Urca cooling  Higher c25Mg<->25Na, 23Na<->23Ne : high metallicity
smaller M(wd,0)Delayed C-ig  Higher c  more 58Ni, 56Fe
 Late time spectra: 58Ni, 56Fe(Foley+13)

 Type Iax (2002cx-like) ? low M(ej), M(56Ni), E
3D deflagration @ higher c 
Ejecta + Bound WD remnant (Jordan+12; Kromer+13)

URCA cooling (ONeMg core)

25Mg<->25Na

23Na<->23Ne(Jones+13)

SN Ia Late-Time Spectra

Optical: Leloudas+ 09
NIR: Motohara+ 06

Electron capture elements(Maeda+ 10)

SUBARU/OHS observations of SNe Ia 05W, 03du, 03hv

(Motohara + 2006)

(Jha 2013)

DD, SD  Chandra, Sub-Ch
 sub-Ch Chandra
107-8
109-10[late time 58Ni, 56Fe]
C-detonation ?  C-det
steady C-burning? ONeMg WD
no ignition ?
C-deflag

surface burningc (g cm-3) ~106
DD

Prompt and Delayed C-ignitionSD

He flashes ?
He detonation ?

 C-det

C-deflag