Formation of Dust in Primordial
Supernovae and Its Survival
within the Supernova Remnants
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）

Contents of my talk
1. Introduction
2. Dust formation in the ejecta of Pop III SNe(Nozawa et al. 2003, ApJ, 598, 785)

3. Dust evolution within Pop III SN remnants(Nozawa et al. 2007, ApJ, 666, 955)

1. Introduction

1-1. Cosmic dust
○ Cosmic dust ： solid particle with size of a few Å to 0.1 mm
interplanetary dust, interstellar dust, intergalactic dust …
Milky Way (optical)

Milky way (infrared)

Dust grains absorb UV and optical lights and reemit
it by their thermal radiation at IR wavelengths!

1-2. Interstellar dust in our Galaxy○ Dust in our Galaxy ➔ where and when is dust formed?

composition; graphite (or carbonacious) grains
silicate (SiO2, Mg2SiO4, MgFeSiO4…) grains
size ;

n(a) = f(a)da = a-3.5 da (0.005~0.25 μm)

Mdust / Mgas ~ 1 / 140 (~109 Msun)(e.g., Draine & Lee 1984)
extinction curveamount ;IR spectral featuredepletion of elements

1-3. Formation site of dust
○ Formation site of dust

・ abundant metal (metal; N > 6)・ low gas temperature (T＜~2000 K)・ high gas density (n ＞108 cm-3)－ in the mass-loss winds of AGB stars－ in the expanding ejecta of Type II SNe－ in molecular clouds (growth only)－ novae, red giant, W-R stars, protoplanetary nebulae …

1-4. 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)
・ properties of high-z dust is different from those at low-z (z < 4) ?
QSO SDSS J1148+52 at z=6.4

QSO SDSS1048+46 at z=6.2(Robson et al. 2004)(Maiolino et al. 2004)

1-5. 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., Cozax & Spaans 2004)－ providing additional cooling pathways of gas throughthermal emission (e.g., Schneider et al. 2003, Omukai et al. 2005)－ controlling the energy balance in the interstellar space81-6. Aim of our study
In the previous studies, the composition and size ofdust are assumed to be the same as those in Galaxy,and the amount is treated as a free parameter
Absorption and thermal emission by dust aresensitive to the composition, size, and amount

It is essential to clarify the properties ofdust in the early epoch of the universe!
We aim at revealing the composition, size, andamount of dust by taking account of the formationand destruction processes of dust self-consistently
91-7. 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)

stars of M=140-260 Msun explode as pair-instability SNe
chemical evolution models of dust
➔ dust of 0.1-1 Msun per SN are required to form
(Morgan & Edmunds 2003, Maiolino et al. 2004; Dwek et al. 2007)

2. Dust formation in the ejecta ofPopulation III supernovae

2-1. Dust formation in the ejecta of SNe
at ~1 days
He-coreH-envelope
NS or BH
He–layer (C>O)
O–Ne-Mg layer
Dust formationSi–Slayer
at ~1-3
years
after explosion
Fe–Nilayer

2-2-1. Calculations of dust formation○ 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 density and temperature of gas－ ρ(t) = ρ0 ( t / t0 )-3－ T(t) is 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)2-2-2. Calculations of dust formation○ nucleation and grain growth theory(Kozasa & Hasegawa 1987)

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

key species controls thekinetics of the nucleationand grain growth2-2-3. Calculations of dust formation
Steady-state nucleation rate
2

Supersaturation ratio

2-2-4. Calculations of dust formation
Equation of conservation for key species

Equation of grain growth2-3. 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 of dust is 300-600 days

2-4. 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

2-4. Dust formed in the unmixed ejecta

2-5. 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 Al2O3
is lognormal-like2-6. 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 for the mixed case is generally larger than for
the unmixed case

2-7. Summary of dust formation○ composition of dust

・ unmixed caseC, Si, Fe, FeS, Al2O3, MgSiO3, Mg2SiO4, SiO2, MgO・ mixed case
MgSiO3, Mg2SiO4, SiO2, Fe3O4, Al2O3○ size distribution of dust
・ for each dust species ; lognormal-like or power-law-like・ over all dust grains ; broken power-law○ total mass of dust
SNe II (8-40 Msun) ： Mdust = 0.1-2 Msun

PISNe (140-260 Msun) ： Mdust = 10-60 Msun

3. Dust evolution within Pop III
supernova remnants3-1. Dust evolution in a SN remnant

T = (1-2) x104 KnH = 0.1-1 cm-3

He coreFSRSCD

3-2-1. Time evolution of shock wave

3-2-2. 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

3-4-1. Erosion rate of dust by sputtering3-4-2. Erosion rate of dust by sputteringfor primordial composition gas

for oxygen ions・ 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 M☉ (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 M☉ (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-sized grains

3-8. Total mass of surviving dust

Total mass of surviving dust decreases with increasing theambient gas density
for Type II SNRs;
0.01-0.8 Msun in the unmixed case (nH,0 = 0.1-10 cm-3)
0.001-0.7 Msun in the mixed case (nH,0 = 0.1-1 cm-3)

3-9. Summary of dust evolution in SNRs
・ 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

・ 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