Formation and Survival ofDust in Supernovae
Takaya Nozawa
IPMU (Institute for the Physics and Mathematicsof the Universe, Univ. of Tokyo)
Collaborators
T. Kozasa, A. Habe (Hokkaido Univ.), Eli Dwek（NASA）
H. Umeda（Univ. of Tokyo）, N. Tominaga（NAOJ）
K. Maeda（IPMU）, K. Nomoto（IPMU/Univ. of Tokyo）
M. Tanaka, T. Suzuki, I. Sakon, T. Onaka (Univ.of Tokyo)
M. Limongi (INAF)

Contents of this talk
1. Introduction

2. Dust formation in primordial SNe
3. Dust evolution in primordial SNRs
4. Thermal emission of dust in Cas A SNR2

1. Introduction

1-1. Dust in the high-z universe○ Evidence of dust at redshift z > 5 (< 1.2 Gyr)・ estimated dust mass : 108 -109 Msun
(Bertoldi et al. 2003; Robson et al. 2004; Beelen et al. 2006)

QSO SDSS
SDSS1048+46QSO
J1148+52atatz=6.2
z=6.4(Maiolino et al. 2004)(Robson et al. 2004)

dust of 0.1-1 Msun per SN
are required to form
(Morgan & Edmunds 2003;
Maiolino et al. 2004; Dwek et al.
2007)

properties of dust at high-z(z > 5) are different fromthose at low-z (z < 4)(Maiolino et al. 2004; Stratta et al.
2007; Willot et al. 2008)

1-2. Role of dust in the early universe
・ Dust absorbs stellar light and re-emits it by thermal radiation➔ plays a crucial role in interpreting the underlying physics
in the early universe from high-z observations(e.g., Loeb & Haiman 1998)

・ Dust has great impacts on the formation processes of stars－ forming molecules (mainly H2) on the surface(e.g., Cazaux & Spaans 2004)－ providing efficient cooling pathways of gas in metal-poor
molecular clouds through thermal emission(e.g., Schneider et al. 2003, Omukai et al. 2005)－ controlling the energy balance in the interstellar space51-3. Aim of our study
In the previous studies, the composition and size ofdust were assumed to be the same as those in ourGalaxy, and the amount was treated as a parameter
Absorption and thermal emission by dust aresensitive to its composition, size, and amount

It is essential to clarify the properties ofdust in the early epoch of the universe!
Our aim is to estimate the composition, size, andamount of dust by taking account of the formationand destruction processes of dust self-consistently
61-4. Sources of dust in the early universe
・ At z > 5, AGB stars (< 8 Msun) can not supply a copious
amount of dust into the interstellar medium

the main formation sites of dust are considered to bein the ejecta of Type II SNe (M = 8-40 Msun)・ first stars (Population III stars); very massive (100-500 Msun)(e.g., Nakamura & Umemura 2001; Bromm et al. 2002)

stars of M=140-260 Msun explode as pair-instability SNe(Fryer et al. 2001; Umeda & Nomoto 2002; Heger et al. 2002)

2. Dust Formation in Primordial SNe
at ~1 days
He-coreH-envelope
NS or BH
He–layer (C>O)
O–Ne-Mg layer
Dust formation
Si–Slayeryears
at ~1-3
after explosion
Fe–Ni layer

2-1. Calculations of dust formation○ nucleation and grain growth theory(Kozasa & Hasegawa 1987)○ models of Pop III SNe (Umeda & Nomoto 2002)－ SNe II ： Mpr = 13, 20, 25, 30 Msun (E51=1)－ PISNe ： Mpr = 170 Msun (E51=20), 200 Msun (E51=28)○ time evolution of gas temperature－ calculated by the radiative transport calculations taking
account of energy deposition from 56Ni and 56Co

○ mixing of elements within the He-core－ unmixed case (onion-like composition)－ uniformly mixed case (retaining the density profile)2-2. Dust formed in the unmixed ejecta

・ In the unmixed ejecta, various dust species form, reflecting
the difference of elemental composition in each layer
・ C, SiO2, and Fe grains have lognormal-like size distribution,
while the other grains have power-law-like size distribution

2-3. Dust formed in the mixed ejecta

・ Because oxygen is rich in the mixed ejecta, only silicates(MgSiO3, Mg2SiO4, SiO2) and oxides (Fe3O4, Al2O3) form
・ The size distribution of each dust species except for Al 2O3
is lognormal-like2-4. Total mass of dust formed
SNe II・ Total dust mass increases with increasing progenitor mass
SNe II ： Mdust = 0.1-2 Msun PISNe ： Mdust = 10-60 Msun
・ Dust mass is generally higher for the mixed case than for
the unmixed case

3. Dust Evolution in Primordial SNRs
T = (1-2) x104 K
nH = 0.1-1 cm-3

He coreFSRSCD

3-1. Time evolution of shock wave

3-2. Initial condition for shock wave
○ SN ejecta models (Umeda & Nomoto 2002)
・ SNe II : Mpr=13, 20, 25, 30 Msun (E51=1)
・ PISNe : Mpr=170 (E51=20), 200 Msun (E51=28)○ The ambient medium
・ primordial composition (uniform)・ gas temperature ; T = 104 K・ gas density ; nH,0 = 0.1, 1, and 10 cm-3
(e.g., Kitayama et al. 2004; Machida et al. 2005)

The calculation is performed from 10 yr up to ~10 6 yr

3-3. Dynamics of dust・ dust model : results of dust formation calculations
・ treating (spherical) dust grains as test particles
・ neglecting the effects of charge of dust

3-4. Erosion rate of dust by sputteringfor primordial composition gas

・ the erosion rate by sputtering quickly increases above 10 5 K
and peaks at 107 -108 K
・ da / dt ～ 10-6 nH μm yr-1 cm3 for T > 106 K and primordial gas

3-5. Temperature and density of gas
Model : Mpr=20 Msun (E51=1)
nH,0 = 1 cm-3
Downward-pointing arrows:
forward shock in upper panel
reverse shock in lower panel

The temperature of the gas
swept up by the shocks➔ 106-108 K↓

Dust grains residing in this hot
gas are eroded by sputtering3-6. Evolution of dust in SNRs
Model : Mpr=20 Msun (E51=1)
nH,0 = 1 cm-3
Dust grains in the He core collidewith reverse shock at (3-13)x103 yr

The evolution of dust heavily
depends on the initial radiusand compositionaini = 0.01 μm (dotted lines)➔ completely destroyedaini = 0.1 μm (solid lines)➔ trapped in the shellaini = 1 μm (dashed lines)➔ injected into the ISM

3-7. Size distribution of surviving dust

The size distribution of surviving dust is greatly deficient insmall-sized grains, compared with that at its formation➔ Dust in the early universe is dominated by large-sizedgrains of > 0.01 μm

3-8. Total mass of surviving dust

Total mass of surviving dust decreases with increasing theambient gas density
for Type II SNRs;
0.1-0.8 Msun in the unmixed case (nH,0 = 0.1-1 cm-3)
0.001-0.7 Msun in the mixed case (nH,0 = 0.1-1 cm-3)

3-9. Summary (1)・ The fates of dust grains within SN remnants depend on
their initial radii and compositions
・ The size distribution of dust surviving the destruction isweighted to relatively large size (> 0.01 μm)

・ The mass of surviving dust decreases with increasing theambient gas density (and explosion energy of SNe)for nH,0 = 0.1-1 cm-3
SNe II ➔ Mdust = 0.1-0.8 Msun for the unmixed casePISNe ➔ Mdust = 0.1-15 Msun
➔ high enough to explain the content of dustin high-redshift galaxies

4. Thermal emission of dust inCas A SNRs

4-1. Introduction○ Dust in SNetheoretical studies : Mdust=0.1-1 Msun
(Bianchi & Schneider 2007; Nozawa et al. 2007)

observations : Mdust=10-4-10-3 Msun(e.g., Hines et al. 2004, Elcolano et al. 2007)

It is still debated whether SNe can be the importantsources of the interstellar dust

In order to examine the causes of this difference,
it is important to compare our calculations withobservation

4-2. Cassiopeia A SNR○ Cas A SNR
age : ~340 yr (Thorstensen et al. 2001)
distance : d=3.4kpc (Reed et al. 1995)
dust mass : Mdust = 0.02-0.05 Msun (Rho et al. 2008)
SN type : (Type IIb SN)

Krause et al. (2008)

4-3. Dust formation calculation○ Type IIb (1993J-like) model (Tominaga et al. 2005)－ Mpr = 18 Msun
Mej= 2.94 Msun
MH-env = 0.08 Msun

Type IIb－ E51 = 1－ M(56Ni) = 0.07 M☉
average radius○ dust formation
theory・ non-steady nucleation andgrain growth theory(Nozawa et al. 2003)

・ onion-like composition
・ sticking probability; αs = 1

Type II at 600days

4-4. Evolution of dust in Cas A SNR

4-5. Time evolution of dust mass
n=1.0 /cc

Mdust~10-4 Msun at 105 yr

n=10.0 /cc

Mdust=0 Msun at 105 yr

This type of SNe (Type IIb) cannot be the main sources of dust

4-6. Thermal emission from dust in the SNR・ thermal radiation from dust  temperature of dust
・ temperature of dust in SNR is determined by collisional
heating with gas and radiative cooling
H (a, n, Tg)= Λ(a, Qabs, Td)  equilibrium temperature Td thermal emission
・ small-sized dust grains (<0.01 μm) undergo stochastic heating
 not equilibrium

the time evolution of thermal radiation including stochastic
heating, based on the dust evolution model

4-7. Comparison with Cas A observation (1)Data; Hines et al. (2004)

4-8. Comparison with Cas A observation (2)Data; Hines et al. (2004)

the dust mass of 0.04 Msun is consistent with the dust mass(~0.02-0.05Msun) in Cas A derived by Rho et al (2008)

4-9. Summary(2)1) The size of dust formed in the ejecta of H-deficient Type IIb
is relatively small because of low gas density of the ejecta.

2) Newly formed dust grains cannot survive the reverse shockowing to their small size.
3) Thermal radiation from dust well reflects the size of dust in
SNR through the effect of stochastic heating.

4) Model of dust formation and destruction of Type IIb SN for
nH=10.0 cm-3 fairly reproduces the observed SED of Cas A.
5) Dust grains in and around SNe can be powerful probes forunderstanding the properties and evolution history of theprogenitor stars.

4-10. Case of SN 2006jc
small grains in SN 2006jc(Type Ib)

best fitted result

early formation of C dust
at 50 days
(Nozawa et al. 2008)
NIR-MIR observations withAKARI and MAGNUM(Sakon et al. 2008)
theory of stellar evolution and calculation of light curve(Tominaga et al. 2008)➔ properties of SN 2006jc (E51, stellar mass at explosion),
evolution history of the progenitor star

5. Formation of dust in SN 2006jc

5-1. Evidence for dust formation in SN 2006jc
KHJDi Calro et al. (2008)
Tominaga et al. (2008)

Anupama et al. (2008)
Tominaga et al. (2008)

Smith et al. (2008)

・ re-brightning of NIR
・ rapid decline of optical light・ blueshift of He I narrow lines

ongoing formation of dust
from ~50 days in SN2006jc

5-2. Composition of newly formed dust
51d75d800K aC
Sakon et al. (2008)

102d128d・ fitting to red/NIR continumat 75-102 days
➔ graphite of ~1600 K・ fitting to NIR/MIR continuumat 200 days
Smith et al. (2008)➔ amorphous C of 800 K

5-3. Dust formation in dense cooling shell?
・Dust grains are newly formed indense cooling post-shock shell?
(Smith et al. 2008; Mattila et al. 2008)

・Dense shell was created by theoutburst 2 yr before explosion

SNejectahydrodynamic calculations for theejecta-CSM interaction➔ estimated CS density profile;ρ = 10-13 (r / 3 x 1010)-1 g/cm3(Tominaga et al. 2008)

Tominaga et al. (2008)

density of shocked region＜critical density for dust formation~10-16 –10-14 g cm-3

5-4. Aim of this study
We investigate the possibility of an early formationof dust grains in the expanding ejecta of SN 2006jc－ very earlier dust formation?
－ high temperature of newly formed dust?
－ time evolution of line profiles?

Dust-forming SNe・Type II (SN1987A, SN1999em, SN 2003gd)➔ 400-500 days
・Type IIn (SN1998S) ➔ ~230 days
・Type Ib (SN1990I) ➔ ~230 days
・Type Ic
➔ not observed

Formation process of dust in the ejecta depends
on the type of SNe?

5-5. Dust formation calculation○ supernova model (Tominaga et al. 2008)－ Mej = 4.9 M☉(MMS = 40 M☉, MpreSN = 6.9 M☉)－ E51 = 10(hypernova-like)－ M(56Ni) = 0.22 M☉○ dust formation theory
・ non-steady nucleation andgrain growth theory(Nozawa et al. 2003)

・ onion-like composition
・ sticking probability; αs = 1

5-6. Condensation time of dust
The quick decreaseof gas temperature
C grains are formed
at 40-60 days in theoutermost ejecta

SNejecta

・ Silicates and oxide grains can condense at 90-150 days
・ FeS and Si grains are formed at ~200 days

5-7. Average radius and mass of dust
average radius

dust mass・ Average radius of each dust species is confined to be lessthan 0.01 μm because of the low gas density
・ The total dust mass : 1.45 M☉ (C grains : 0.7 M☉)

5-8. Temperature of newly formed dust

5-9. Dust temperature at 60 and 200 days
・ Temperature ofC grains
at 60 days
➔ 1200-1700 K

at 200 days
➔ 500-600 K

・ Temperature of silicates and oxides is 100-200 K at 200 days
・ FeS grains ➔ ~900 K at 200 days
Si gains➔ ~1300 K at 200 days

5-10. IR spectral energy distribution

The IR spectrum obtained byadopting the results of dust
formation calculation cannot
reproduce the observed SED

5-11. IR spectral energy distribution fitting
bestprobability
fitted result α ; parameter
stickingsC grains ➔ αs ~3 x 10-3
FeS grains ➔ αs ~0.3

The difference in αs may becaused by destruction of smallsized clusters by collisions withenergetic photons and electrons
within the ejecta at earlier epoch・ C grains ➔ 5.6 x 10-4 M☉ FeS grains ➔ 2 x 10-3 M☉・ the mass of cold silicates and oxides cannot be constrained
The process affecting dust formation is the energy deposition
on small-sized clusters through the latent heat deposition andthe collisions with energetic photons and electrons

5-12. Summary
1. The very early formation of dust at ~50 days in SN 2006jc
can be realized by the condensation in the expanding ejecta,
thanks to the rapid decrease of gas temperature in the ejecta.
2. Average radius of newly formed dust is smaller than 0.01 μm,
because of the low gas density at the time of formation.

3. The calculated temperature of C grains can explain the time
evolution of dust temperature suggested by the observations.
4. The temperature of silicates and oxides at 200 days is toocold to explain the MIR spectrum observed by AKARI.

5. The difference between calculated and evaluated masses of
C and FeS grains may be explained by the destruction ofsmall-sized clusters due to energetic photons and electrons.