Formation and Destructionof Dust in Supernovae（超新星爆発時のダストの形成と破壊）

Takaya Nozawa
IPMU (Institute for the Physics and Mathematicsof the Universe, University of Tokyo)
Collaborators;
T. Kozasa (Hokkaido Univ.), A. Habe (Hokkaido Univ.),
H. Umeda (UT), K. Maeda (IPMU), E. Dwek (NASA),
N. Tominaga (NAOJ), K. Nomoto (IPMU/UT)Outline
1. Introduction

2. Dust formation in primordial SNe(Nozawa et al. 2003)

3. Dust evolution in primordial SNRs
(Nozawa et al. 2007)

4. Summary and ongoing works

1-1. A large amount of dust at z > 5・ The presence of large amounts of dust grains with mass of>10^8 Msun has been confirmed for ~30% of z > 5 quasars(Bertoldi et al. 2003; Priddey et al. 2003; Robson et al. 2004;
Beelen et al. 2006; Wang et al. 2008a, 2008b)
SDSS J1148+5251 at z=6.4
LIR>10^13 Lsun
180 K, β=040 K, β=2a rapid enrichment with dust
formed in the ejecta of SNe
0.1-1 Msun of dust per SN isrequired to form to explain alarge content of dust at high-zgalaxies

Robson et al. (2004, MNRAS, 351, L29)

(Morgan & Edmunds 2003,
Maiolino et al. 2006;
Dwek et al. 2007)

1-2. Extinction curves at high-z
Broad absorption line (BAL) quasars at low-z➔ reddened by dust
SDSS J1048+4637 at z=6.2
GRB 050904 at z=6.3

Maiolino et al. (2004, Nature, 431, 533)

Stratta et al. (2007, ApJ, 661, L9)

Source and evolution of dust at high redshift (z > 5)
are different from those at low redshift (z < 4)

1-3. Role of dust (in the early universe)
・ Dust has great impacts on the formation processes of galaxies－ controlling the energy balance in the interstellar space－ forming molecules (mainly H2) on the surface(e.g., Cazaux & Spaans 2004; Hirashita & Ferrara 2002)－ providing efficient cooling pathways of gas in metal-poor
molecular clouds through thermal emission(e.g., Omukai et al. 2005; Schneider et al. 2006)

・ Dust absorbs stellar light and re-emits it by thermal radiation➔ plays a crucial role in determining the SFR and the IMF
from observations(e.g., Takeuchi-san’s talk)Absorption and thermal emission by dust are
sensitive to the composition, size, and amount1-4. Aim of our study
In the previous studies, composition and size of dust
are assumed to be the same as those in our Galaxy,
and the amount is treated as a parameterto understand the evolution history of galaxies
from both theoretical and observational studies
It is essential to reveal the evolution ofdust grains throughout the cosmic age!
We aim at revealing the composition, size, andamount of dust by treating the formation anddestruction processes of dust self-consistently

1-5. Sources of dust in the early universe
・ At z > 5, the main formation sites of dust are considered
to be in the ejecta of core-collapse SNe・ Population III stars ➔ very massive (Mpr =100-500 Msun)(e.g., Nakamura & Umemura 2001; Bromm et al. 2002)

In the early universe
・ Type II SNe (SNe II)；Mpr=8-40 Msun

・ pair-instability SNe；Mpr=140-260 Msun
(Heger et al. 2003, ApJ, 591, 288)

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–S
layeryears
at ~1-3
afterlayer
explosion
Fe–Ni2-1-1. Calculations of dust formation
・ nucleation and grain growth theory taking accountof chemical reaction at condensation(Kozasa & Hasegawa 1987)

・ key species：
gas species with the least
collision frequency among
reactants

key species controls thekinetics of the nucleationand grain growth2-1-2. Nucleation rate of dust
Steady-state nucleation rate

Supersaturation ratio

2-1-3. Basic equations of dust formation
Equation of conservation for key species

Equation of grain growth2-2. Models of dust formation calculation
・ 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－ ρ(t) = ρ0 ( t / t0 )-3－ T(t) is calculated by solving the radiative transfer 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)・ formation of CO and SiO molecules ➔ complete

2-3. Behavior of dust formation

2-4. Dust formation in the unmixed ejecta

・ Various dust species (C, MgSiO3, Mg2SiO4, SiO2, Al2O3,MgO, Si, FeS, Fe) form in the unmixed ejecta, reflecting
the elemental composition in each layer
・ The condensation time; 300-600 days for SNe II
400-800 days for PISNe

2-5. Dust formed in the unmixed ejecta

・ C, SiO2, and Fe grains have lognormal-like size distribution,
while the other grains have power-law-like size distribution
・ The composition and size distribution of dust formed arealmost independent of type of supernova

2-6. 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2-7. Total mass of dust formed
SNe II・ Total dust mass increases with increasing progenitor mass
SNe II ： Mdust = 0.1-2 Msun, fdep = Mdust / Mmetal = 0.2-0.3
PISNe ： Mdust =10-60 Msun, fdep = Mdust / Mmetal = 0.3-0.5
・ Dust mass for the mixed case is generally larger than for
the unmixed case

3. Dust Evolution in Primordial SNRs
T = (1-2) x104 K
nH,0 = 0.1-1 cm-3
(Kitayama et al. 2004;Machida et al. 2005)

He coreFSRSCD

3-1-1. Time evolution of shock wave

3-1-2. Initial condition for shock wave
・ Hydrodynamical model of SNe (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 (homogeneous)・ gas temperature ; T = 104 K・ gas density ; nH,0 = 0.1, 1, and 10 cm-3

・ Model of Dust・ initial size distribution and spatial distribution of dust
➔ results of dust formation calculations
・ treating as a test particle (neglecting the effects of charge)
The calculation is performed from 10 yr up to ~106 yr

3-2-1. Dynamics of dust

3-2-2. Erosion rate of dust by sputtering3-2-3. Erosion rate of dust by sputteringfor primordial composition gas

for oxygen ions・ 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 the primordial gas withT > 106 K

3-3.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3-4. 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 yrThe 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

3-5. Size distribution of surviving dust

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

3-6. Total mass fraction of surviving dust
星間空間中の密度が大きいほど、生き残るダストの質量は小さい

完全に破壊されるダストの初期サイズ
aini ＜～0.01μm for nH,0 = 0.1 cm-3
aini ＜～0.05μm for nH,0 = 1 cm-3
aini ＜～0.2μm for nH,0 = 10 cm-3・ mixed caseで形成されたダストはunmixed caseで形成されたダストよりも破壊されやすい
・ PISNeで形成されたダストはSNe IIよりも破壊されやすい

3-7. Total mass of surviving dust

Total mass of dust surviving the destruction for Type II SNRs;
0.1-0.8 Msun for the unmixed grain model (nH,0 = 0.1-1 cm-3)
0.06-0.7 Msun for the mixed grain model (nH,0 = 0.1 cm-3)➔ high enough to explain dust content at high-z galaxies(Morgan & Edmunds 2003, Maiolino et al. 2006; Dwek et al. 2007)

Summary
・ 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

Ongoing work・ dependence of dust formation on the initial metallicity(Z) of progenitor star and type of SNe
・ comparison with observations➔ insights into the fundamental processes of formationand destruction of dust
－ formation of dust in SN Ib (peculiar SN 2006jc)(Nozawa et al. 2008)－ formation of dust in SNe IIb and its evolution➔ Cas A SNR－ formation of dust in SNe Ia, in mass-loss winds ofAGB stars and massive stars? and quasar winds?

－ destruction of ISM-dust by SN shock (Nozawa et al. 2006)➔ including grain-grain collision