2019/08/28

Probing the formation anddestruction processes of dustwith large MIR telescopes
Takaya Nozawa(National Astronomical Observatory of Japan)

SNR 1E0102-72.3

SN 1987ALBV AFGL2298

1-1. Paradox in interstellar dust mass
〇 Injection rate of dust from CCSNe/AGB stars

SFR

Fraction ofMass fraction Condensationstars evolving of gas ejected efficiency of dust
to SNe/AGB
from SNe/AGB〇 Destruction rate of interstellar dust by SN shocks

SN rateGas mass
swept by aSN shock

Dust-to-gas
mass ratio

Destruction
efficiency of dust

Formation rate of dust in stellar sources islower than destruction rate of dust
➜ Interstellar dust must decrease with time

1-2. What is wrong?
〇 Underestimate condensation efficiency of dust?
- CCSNe eject ~10 Msun gas and ~0.1 Msun dust

~90% of dust destroyed by reverse shocks
fdust,form = 1 % would be the optimistic estimate〇 Overestimate destruction efficiency of dust?

- There is uncertainties in destruction efficiency- Dust is destroyed by sputtering in shocked gas〇 Other sources of interstellar dust?
- RGs, RSGs, sAGB stars, LBVs, WR stars, Novae, …
- Grain growth in molecular clouds

2-1. Observed dust mass in CCSNe/SNRs

NIR/MIR
FIR/submm
extinction

Balow+2010

Gomez+2012

Indebetouw+2014, Matsuura+2011

Dust mass formed in the ejecta is dominated by cold dust

2-1. Observed dust mass in CCSNe/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

2-2. Origin of IR emission from CCSNe
Dust formation in the ejecta〇 SN 1987A
with Kuiper Airborne Observatory- dust mass : > ~10-4 Msun(optically thin assumed)
60 day260 day

415 day

615 dayIR echo by CS dust

Wooden+93

2-3. Rapid decline of light curve in SN 1987A
Optical light curve

OI 6300 emission line

Bevan & Barlow 2016

Whitelock+1989

Optical light curve starts to decline around 400 day➜ dust starts to form at ~400 day in the ejecta

2-4. CO and SiO molecules in SN 1987A
CO first overtone: 2.29-2.5 μm
CO fundamental: 4.65-6 μm
SiO fundamental: 7.6-9.5 μm

260 day- Mco~4x10-3 Msun (Liu+1995)- MSiO~7x10-4 Msun
(Liu & Dalgarno 1996)

Iron group elements in MIR- [Fe II] 1.26, 17.9, 26.0 µm- [Ni II] 6.63, 7.51 µm- [Co II] 10.52 µm
Abellan+2017, t~28 yr415 day

615 day

Wooden+1993

CO (2-1)
SiO (5-4)
Colgan+1994

2-5. Observations of dust formation in SNe〇 Long-time monitoring of nearby CCSNe- emission lines of CO and SiO molecules in N/MIR- thermal emission from newly formed dust in N/MIR- Extinction of light curve in optical- Blueshift of atomic emission lines in optical thru MIR
monitor : from 100 to 1000 days
nearby : <20 Mpc (~1 SN per yr)➜ should focus on a few targets※ suspect that JWST can monitora SN every 6 month

SPICA
JWST
MICHI
MIMIZUKU

3-1. Observed dust mass in CCSNe/SNRs
reverse shock
destruction??
missingcold dust?

Dust mass
increasingwith time?

??

NIR/MIR
FIR/submm
extinction

Dust mass formed in the ejecta is dominated by cold dust

3-2. Destruction of dust in Cassiopeia A SNR
ALMA, 450 µm

0.008Msun of shocked
warm dust

0.07Msun of unshocked
cool dust

Chandra, X-ray

SN 1987A at 28 yr
Nozawa+2010

Nozawa 2014

Cas A at 330 yr

AKARI, Sibthorpe+2010

3-3. CO detection in Cassiopeia A SNR
Herschel PACS

AKARI IRC spectra

CO (4.5 μm)
dust (21 μm)

Rho+2012
Cas A at ~330 yr
Wallstrom+2013

3-4. Possible target: SNR 1E0102-72.3 in SMC〇 SNR 1E0102-72.3 in SMC

X-ray, radio- O-rich (similar to Cas A)- age : ~1000 yr- Mwarm ~ 10-3 Msun
- Mcool ~ ???
40 arcsec➜ spatial distributions of CO
and dust with TAO/MIMIZUKUGaetz+2000
24 μm- what is the initial dust mass?
- how efficient is dust destruction?
- what fraction of dust can survive
to be injected into the ISM?
※ SNR age : ~>105 yr
Stanimirovic+2005

3-5. Destruction rate of dust by sputtering〇 Erosion rate of dust by sputtering

Sputtering yieldTargets of experimental databulk materials, crystal, no void, smooth surface, …

3-7. Destruction of dust by sputtering〇 Erosion rate of dust by sputtering〇 Erosion rate of inner wall of nuclear fusion

Is this erosion rate correct？

4-1. Expected IR images of SN 1987A
on 4 Oct 2003
Gemini T-ReCS(λ = 10.36 μm)
2 pixels : 0.18”

SN 87A with MIMIZUKU(Bouchet+2004)- spatially resolving
equatorial ring
- multi-epoch (monitoring)➜ evolution of CS dust
- MIR flux: 10-100 mJy

AKARI
24 μm(Seok+2008)

Chandra image(Park+2007)

On 6 Jan and 1 Feb 2005 (Bouchet+2006)

4-2. Properties of CS dust around SN 1987A
IR light curve

MIR SEDs

Spitzer observation (Dwek+2010)

・ IR fluxes increase inall bands by a factorof ~3 between 17 yrand 22 yr
・ properties of CS
dust in ER
silicate
Tdust = 180 K
Mdust = ~10-5 Msun
LIR = 1036-1037 erg/s(Seok+2008, Dwek+2008)

・ grain radius:a = 0.02-0.2 μm➔ relatively large
Dwek+2008

4-3. Re-formation of dust in equatorial ring?
○ SOFIA observations of SN 1987A
・ 30-70 µm excess appeared at 10000 day- cool dust = ~4x10-4 Msun
➜ re-formation of dust in the ring??
- hot dust = ~10-5 Msun

Matsuura+2016

Eta Carina

5-1. What is LBVs?
○ LBVs (luminous blue variables)‐ log10(L / Lsun) = 5.5-6.5‐ log10(Teff / K) = 3.8-4.6➜ Mstar = 40-150 Msun
Eta Carina

17 LBVs in our Galaxy (at Mar 2016）〇 Is Type IIn SN 2005gl
explosion of a LBV?

Gal-Yam & Leonard 2007, 2009
Wikipediaより➜ Challenge to the stellar
evolution theory5-2. Dusty envelopes around LBVs
Eta Carina
TIMMI 17 µm
Morris+1999

HR CarSpitzer 8 µm
Umana+2009

G24.73
MSX 7-25 µm
Clark+2003

MWC 930
WISE 22 µm
Cerrigone+2014

AG CarWray15-751
Herschel 70 µm
Herschel 70 µm
Vamvatira-Nakou+2015 Vamvatira-Nakou+2013

Wray16-137
Spitzer 24 µm
Gvaramadze+2014

WS1
WISE 22 µm
Gvaramadze+2012

AFGL2298
VISIR 17.65 µm
Buemi+2010

MN44
Spitzer 24 µm
Gvaramadze+2015

70% of LBVs have thick circum-dust envelopes➜ dust formation in mass-loss winds

5-3. Dust formation in mass-loss winds of LBVs
○ Two difficulties of dust formation in LBVs
- fast wind velocity (~100-300 km/s) ➜ low gas density

ρgas = Mdot / ( 4 π r2 vwind)cf. vwind = 10-30 km/s for AGB stars- high BB temperature ➜ dissociation of dust by UV radiation

Studies of dust formation in LBVs are challenging !!
○ Dust formation in dense clumps?
‐high gas density, shielding of UV photons

Spatial distribution of CS dust
➜ N/MIR high spatial-resolution
mapping of LBVs

Wray15-751
Vamvatira-Nakou+2013

5-4. Most LBVs only from southern hemisphere○ 16 of 17 LBVs in southern sky➜ ideal targets to be observedby TAO/MIMIZUKUP Cygni

AKARI FIR images, Credit: JAXA/ISAS

Eta Carina

5-5. Significance of studying LBVs
○ Important topics related to LBVs
‐Dust formation processes in extreme environments➜ laboratories that probe dust condensation in space‐Mechanisms of (explosive) mass loss
➜ mass-loss rate, asymmetry of ejected gas‐Relationship with Type IIn SNe➜ Are LBVs progenitor stars of Type IIn SNe?

‐Understanding of massive star binaries➜ many of LBVs are binaries

Observations of LBVs ➜Dust formation theory
Stellar evolution theory

Obs targets w.r.t. dust formation/destruction(1) long-term monitoring of nearby CCSNe with TMT➜ line emissions of CO/SiO and Fe group elements➜ IR emission and optical extinction of dust grains(2) young SNRs in LMC/SMC➜ spatial distribution of CO and dust grains➜ dust destruction of dust by reverse shocks(3) MIR monitoring of SN 1987A with TAO/MIMIZUKU➜ evolution of dust in the equatorial ring
➜ derivation of dust destruction efficiency(4) IR mapping observations of Galactic LBVs
➜ most of LBVs are seen only from southern sky