Composition and Origin of Dust
Probed by IR Spectra of SNRs
(超新星残骸の赤外分光観測から探るダストの組成と起源)

Takaya Nozawa
IPMU (Institute for the Physics and Mathematicsof the Universe, Univ. of Tokyo)

Collaborators
T. Kozasa (Hokkaido University), N. Tominaga（NAOJ）,
H. Umeda（UT）, K. Maeda（IPMU）, K. Nomoto（IPMU/UT）Contents
1. Introduction

2. Cassiopeia A SNR
3. Calculation of evolution of dust inCas A-like SNR

4. Candidates: Other Galactic SNRs

1-1. Introduction
Supernovae are the important sources of dust?
・ theoretical studies ➔ Mdust = 0.1-1 Msun by SNe II(Bianchi & Schneider 2007; Nozawa et al. 2007)

・ large amounts of dust (108 -109 Msun ) for QSOs at z > 5(Bertoldi et al. 2003; Priddy et al. 2003; Robson et al. 2004)
QSO SDSS J1148+52 at z=6.4(Robson et al. 2004)

0.1-1 Msun of dust per SN II
are required to form
(Morgan & Edmunds 2003;
Maiolino et al. 2006;
Dwek et al. 2007)

SNe are dust factory!

1-2. Introduction○ IR observaitons of dust-forming SNe (~10 SNe)
Mdust = 10-5-10-3 Msun
SN 1987A ➔ 10-4-10-3 Msun (Elcolano et al. 2007)
SN 2003gd ➔ 0.02 Msun (Sugerman et al. 2006)➔ 4x10-5 Msun (Miekle et al. 2007)
SN 2006jc ➔ ~7x10-5 Msun (Sakon et al. 2008)➔ 6x10-6 Msun (Smith et al. 2008) , 3x10-4 Msun (Mattila et al 2008)○ IR observaitons of nearby young SNRs
Mdust = 10-4-10-2 Msun(e.g., Hines et al. 2004, Temim et al. 2006; Morton et al. 2007)

Theoretical predictions overestimate dust mass?
Observations are seeing only hot dust (＞100K)?

1-3. Aim of our study
How much and what kind of dust are supplied by SNe?
It is necessary to combine theoretical models withIR observational results

・ Observations ofongoing formation of dust in SNe (see Sakon’s poster)
nearby young SNRs

・ Theoretical studies ofdust formation in the SN ejecta➔ mass, size, and temperature of dust
dust evolution in the shocked gas within SNRs
➔ destruction by sputtering, dynamics, heating➔ Cas A SNR

2-1. Cassiopeia A SNR○ Cas A SNR (SN 1671)
age: 337yr (Thorstensen et al. 2001)
distance: d=3.4 kpc (Reed et al. 1995)
radius: ~150” (~2.5 pc)
SN type : Type IIb (Mpr=15-25 Msun)

Krause et al. (2008)

2-2. Dust in Cas A SNR○ Estimated mass of dust in Cas A
・ warm/hot dust (50-300K)(3-7)x10-3 Msun (IRAS, Dwek et al. 1987)~7.7x10-5 Msun (ISO, Arendt et al. 1999)~6x10-4 Msun (ISO, Douvion et al. 2001)~3x10-3 Msun (Spitzer, Hines et al. 2004)
・ cold dust (~18K)
2.2-26 Msun (SCUBA, Dunne et al. 2003)
no cold dust (Krause et al. 2004)＜1.5 Msun (Wilson & Batrla 2005)

2-3. Latest estimate of dust mass in Cas A(Rho et al. 2008)

Emission lines allow us to specify the composition of dust

➔ Mdust = 0.02-0.054 Msun

3-1. Dust formation calculation○ Type IIb (1993J) model－ Mpr = 18 Msun
Mej = 2.94 Msun
MH-env = 0.08 Msun

－ E51 = 1－ M(56Ni) = 0.07 Msun

○ Dust formation theory－ non-steady nucleation andgrain growth theory(Nozawa et al. 2003)－ onion-like composition－ sticking probability; αs = 1

3-2. Results of dust formation calculation
average radius

Low gas density in SN IIb
prevents dust grains fromgrowing up to large radius

dust mass

3-3. Calculation of dust evolution in SNRs
○ Model of calculations
Nozawa et al. (2007)
・ejecta model－ hydrodynamic model fordust formation calculation
・ISM－ homogeneous, Tgas=104 K－ nH = 1.0 and 10.0 cm-3
－ solar composition of gas

・treating dust as a test particle－ erosion by sputtering－ deceleration by gas drag－ collsiional heating3-4. Evolution of dust in Cas A SNR

3-5. Time evolution of dust mass
n=1.0 /cc

n=10.0 /cc

Mdust ~ 10-4 Msun at 105 yr

Mdust = 0 Msun at 105 yr

This type of SNe (Type IIb) cannot be the main sources of dust
※ In Type IIp SNe, dust grains of ＞0.02 μm are formed andcan survive the destruction in SNRs (Nozawa et al. 2007)

3-6. Thermal emission from dust in the SNR・ thermal radiation from dust ➔ temperature of dust
・ equilibrium temperature of dust in SNR is determined bycollisional heating with gas and radiative cooling
H (a, n, Tg)= Λ(a, Qabs, Td) ➔ thermal emission
・ small-sized dust grains (＜0.01 μm) ➔ stochastic heating

3-7. Comparison with Cas A observation (1)Data; Hines et al. (2004)
red: with stochastic
green: without SH

3-8. Comparison with Cas A observation (2)Data; Hines et al. (2004)
red: with stochastic
green: without SH

3-8. Comparison with Cas A observation (2)Data; Hines et al. (2004)
red: with stochastic
green: without SH

Dust mass of 0.04 M sun is consistent with mass of dust(~0.02-0.054 Msun) in Cas A derived by Rho et al. (2008)

3-7. Summary1) 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 shock
since their radii are small (＜0.01 μm)

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 reproduces the observed SED of Cas A➔ circumstellar / interstellar dust
➔ density structure of circumstellar medium➔ thermal emission from dust at various positions

4-1. Crab SNR○ Crab nebula (SN 1054)
age: 954 yr
distance: d=2.1 kpc (Reed et al. 1995)
SN type: Type IIp or IIn?
O-Ne-Mg core, Mms=8-10 Msun (Nomoto et al. 1982)
dust mass: Mdust = 0.003-0.07 Msun (Green et al. 2004)
Mdust = 0.001-0.015 Msun (Temim et al. 2006)
Temim et al. (2006)

4-2. Kes 75 SNR○ Kes 75
age: ~884 yr (Livngstone et al. 2006)
distance: d=19 kpc (Becker & Helfand 1984)
d=5.1-7.5 kpc (Leahy & Tian 2007)
SN type: Type Ib or Ic (W-R star, >20 Msun?) (Chevalier 2005)
dust mass: Mdust = ~0.08 Msun (Morton et al. 2007)

Morton et al. (2007)

4-3. Kepler SNR○ Kepler (SN 1604)
age: 404yr (Kepler 1606)
distance: d=2.5-5.8 kpc (Sankrit et al. 2005)
SN type: Type II or Type Ia?
dust mass: Mdust = 10-4 Msun (Douvion et al. 2001)
Mdust = 0.3-2.7 Msun (17K) (Morgan et al. 2004)
Mdust = 5.4x10-4 Msun (Blair et al. 2007)
Morgan et al. (2004)
Blair et al. (2007)

4-4. Prospects
IR spectroscopic observations of dust in SNRs
・ newly formed dust? and/or circumstellar/interstellar dust?
・ composition of dust ➔ silicate? and/or carbonacious?
・ spectral feature, IR colors
・ forbidden emission lines at IR wavelengths(by comparing with SN nucleosynthesis results)
・ clumpy structure
・ size of dust ➔ properties of the SNe (Eexp and Meje)・ temperature of dust ➔ gas density➔ CSM / ISM structure ➔ mass-loss history

Dust in SNRs can be powerful probes for understanding
the properties and evolution history of progenitor stars!