2018/01/10

Consensus and issues on dust
formation in supernovae
Takaya Nozawa (野沢 貴也)
National Astronomical Observatory of Japan

1-1. Discovery of massive dust at z > 5The far-infrared and submm observations have confirmed thepresence of dust in excess of 108 Msun in 30% of z > 5 quasars
stellaremission

dust
emission

108-109 Msunof dust inSDSS J1148+
5251 at z=6.4
Leipski+2010~106 Msun ofdust in a galaxy
at z = 8.4
Laporte+2017‐In the MW, AGB stars are considered to be major dust
sources ➜ too old to supply dust in the early universe‐0.1 Msun of dust per SN is needed to explain massive
dust at high-z (e.g. Morgan & Edmunds 2003; Maiolino+2006; Dwek+2007)

1-2. Emission and absorption efficiency of dust
○ Thermal radiation from dust grains
Fλ = Ndust 4πa2 Qemis(a,λ) πBλ(Tdust) # Qemis = Qabs
carbonsilicate(Qemis/a) is independent of aFλ = Ndust 4πa3 (Qemis[a,λ]/a) πBλ(Tdust)= 4 Mdust κabs(λ) πBλ(Tdust)➔ IR emission is derived given Mdust, κabs, and Tdust1-3. Formation and processing of dust in SNe
Nozawa 2014, Astronomical Herald

Destruction efficiency of dust grains by sputtering in thereverse shocks depends on their initial size
The size of newly formed dust is determined by physicalcondition (gas density and temperature) of SN ejecta

1-4. Key questions for dust formation in SNe
1. How much dust grains form?

2. What is the size distribution of dust?

3. When do the majority of grains form?

2-1. Observed dust mass in CC-SNe/SNRs

NIR/MIR
Matsuura+2011
FIR/submm
Balow+2010
extinction

Gomez+2012

Dust mass formed in the ejecta is dominated by cold dust

2-2. ALMA reveals dust formed in SN 1987A
ALMA, 1.4 mm

ALMA, 870 µm

ALMA, 450 µm

HST optical (HI)Chandra, X-ray

SED of 25-years old SN 1987A

Indebetouw+2014

ALMA spatially resolves cool(~20K) dust of ~0.5 M sun formedin the ejecta of SN 1987A➔ SNe could be production
factories of dust grains

2-3. Observed dust mass in CC-SNe/SNRs

missing
cold dust?

Dust mass
increasing
with time?

NIR/MIR
FIR/submm
extinction

Dust mass formed in the ejecta is dominated by cold dust

2-4. Interpretation of Gall et al. (2014) paper
Gall+2014, Nature
Dust formed incool dense shell

Dust formed in
the ejecta
Pre-existing
circumstellar dust

The mass of newly formed
dust increases with time?

We should not discuss
the mass of newly formed
grains by integrating theformation of dust in theejecta and CDS

2-5. Timescale of grain growth

At 20 yr, the gas density is too low to form dust
grains in the freely expanding ejecta

2-6. Key questions for dust formation
1. How much dust grains form?
‐theoretical works ➜ 0.1-1 Msun
‐FIR/submm obs. ➜ 0.1-1 Msun

2. What is the size distribution of dust?
➜ what fraction of dust is destroyed by RS?
➜ smaller grains are destroyed more efficiently

3. When do the majority of grains form?
‐theory ➜ ~1-3 yr (within 5 yr; earlier is better)‐obs. ➜ ~20 yr (dust mass gradually increases with time)2-7. Observed dust mass in CC-SNe/SNRs
reverse shock
destruction??
missing
cold dust?

Dust massincreasingwith time?

??

NIR/MIR
FIR/submmextinction

Dust mass formed in the ejecta is dominated by cold dust

3-1. Survival of dust within an old SNR
Sagittarius A East SNR・ age: ~10,000 yr
・ dust mass: ~0.02 Msun・ dust temperature: ~100 K
Lau+2015, Science3-2. Constraining dust size from extinction
OI 6300
SN 1987A

Bevan & Barlow 2016

Lee+2015

・ dust mass < 3x10-3 Msun(< 0.07 Msun if silicate)・ grain radius > ~0.6 µm

cool dust component➜ Fe with a < 0.01 µm(or large Si dust)

3-3. Dust mass and size ejected from SNe II
Nozawa+07, ApJ, 666, 955SNe II-P

total mass of dust surviving thedestruction in Type II SNRs;
0.07-0.8 Msun (nH,0 = 0.1-1 cm-3)
size distribution of dust after theshock-destruction is domimatedby large grains (> 0.1 μm)

3-4. Dependence of grain radii on SN type
SN IIbSN II-P

0.01 μm- condensation time of dust
300-700 days after explosion- the radius of dust formed in
H-stripped SNe is small- total mass of dust formed
・ 0.167 Msun in SN IIb
・ 0.1-1 Msun in SN II-P・ SN IIb without massive H-env➔ adust < 0.01 μm

Nozawa+10, ApJ, 713, 356

・ SN II-P with massive H-env➔ adust > 0.01 μm

3-5. Destruction of dust in Type IIb SNR
stellar-wind CSM (ρCSM ∝ r-2)
330 yrnH,1 = 30, 120, 200 /cc ➔ dM/dt = 2.0, 8.0, 13x10-5 Msun/yr for vw=10 km/s

Almost all newly formed grains are destroyed in the hot gas
that was swept up by the reverse shocks➔ small radius of newly formed grains➔ early arrival of reverse shock at dust-forming region
Nozawa+10, ApJ, 713, 356

3-6. IR emission from dust in Cas A SNRAKARI 90 μm image (color)・ total mass of dust formed
Mdust = 0.167 Msun・ shocked dust : 0.095 Msun
Md,warm = 0.008 Msun
・ unshocked dust :Md,cool = 0.072 Msun
with Tdust ~ 40 K
Nozawa+10, ApJ, 713, 356

AKARI observation
Md,cool = 0.03-0.06 Msun
Tdust = 33-41 K(Sibthorpe+10)

Herschel observation
Md,cool = 0.075 Msun
Tdust ~ 35 K (Barlow+10)

3-7. Formation condition of presolar Al2O3
presolar Al2O3 grains
Al2O3 (Nittler+1997)

Nozawa+2015, ApJ, 811, L39

Submicron-sized presolar Al2O3 grains identified asSN-origin were formed in dense clumps in the ejecta

3-8. Calculated size distribution of SiC grainspresolar SiC grains

Nittler 2003

‐ Radius of newly formed grains is larger for higher gas density‐ In the density range considered in this study, grain radius is notlarge enough to reproduce ones observed in presolar SiC grains

3-9. 3-D structure of Cas A SNR

Milisavljevic+2013

Orlando+2016

Calculations of dust formation and destruction in 3-D
simulations of SNe/SNRs would be highly useful.

3-10. Key questions for dust formation
1. How much dust grains form?
‐theoretical works ➜ 0.1-1 Msun
‐FIR/submm obs. ➜ 0.1-1 Msun

2. What is the size distribution of dust?
‐theory ➜ >0.1 µm in Type II, <0.01 µm in Type IIb‐obs.➜ large (~0.1-1 µm) at the dust formation

3. When do the majority of grains form?
‐theory ➜ ~1-3 yr (within 5 yr; earlier is better)‐obs. ➜ ~20 yr (dust mass gradually increases with time)4. How we tackle unsolved problems?
2. What is the size distribution of dust?
‐would not easy to constrain grain sizes fromoptical/NIR extinction➜ Calculations of dust formation/destruction in 3-D
SN simulations are critical to predict grain sizes➜ SN-origin presolar grains are useful tools to probe
the condition of SN ejecta

3. When do the majority of grains form?
‐JWST will not do a good job to answer this question➜ SPICA will be able to resolve this problem➜ We just expect that a supernova explosion occurs
in MW/LMC/SMC in near future