野沢貴也(Takaya Nozawa)国立天文台理論研究部(National Astronomical Observatory of Japan) Contents: -  Introduction (10 min) -  Current issues on dust formation in SNe (20 min) -  Our r recent work on SN-origin presolar grains (10 min) -  Peculiar extinction laws toward Type Ia SNe (10 min) 60 73億
Dustr in Core-Collabse supernovae near & far: understanding its formation and evolution 5 – 8 November 2012 Monte Verità – Ascona, Switzerland Invited speakers Mike Barlow John Black Stefan Bromley Volker Bromm Roger Chevalier Donald Clayton Eli Dwek Claes Fransson Peter Hoppe Cornelia Jäger Gunther Korschinek Rubina Kotak Francesca Matteucci Mikako Matsuura Ewald Müller Takaya Nozawa Michael Paul Jeonghee Rho Raffaella Schneider Friedel Thielemann Ernst Zinner A CoDustMas network conference Contact: info-ascona@unibas.ch I. Cherchnett (Chair) Switzerland M. Busso Italy S. Muller Sweden U. Ott Germany C. Vockenhuber Switzerland A. Wallner Austria/Australia Fraction of women 20 60 1 Federal loutitude of Fechnology Dirich
time after the explosion (yr) There are increasing pieces of evidence that massive dust in excess of 0.1 Msun is formed in the ejecta of SNe
Nozawa 2014, Astronomical Herald Destruction efficiency of dust grains by sputtering in the reverse shocks depends on their initial size The size of newly formed dust is determined by physical condition (gas density and temperature) of SN ejecta Oこれまでの研究でわかったこと(重力崩壊型)超新星は、放出ガス中で大量(0.1 Msun以上)ののダストを形成することができるO超新星ダスト研究における現在の二つの課題1)観測された大量のダストはいつ形成されたのか？ →中間赤外線と遠赤外線でのダスト量の違いを説明したい2)形成されるダストのサイズはどれくらいか？ →超新星による最終的なダスト放出量を明らかにしたい
Dust formation in the ejecta Dust formation in dense shell IR echo by CS dust Shock heating of CS dust
• brightening of IR • rapid decline of optical light • blueshift of emission lines formation of CO/SiO molecules (more robust if SiO are depleted)
T HE A STROPHYSICAL J U R AL , 776:5 (16pp), 2013 October 10 © 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A. doi: 10.1088/0004-637X/776/1/5 PROPERTIES OF NEWLY FORMED DUST GRAINS IN THE LUMINOUS TYPE IIn SUPERNOVA 2010j1* K. M a da ¹ , T. Nozawa ¹ , D. K. Sahu ² , Y. M inowa ³ , K. M otohara ⁴ , I. U no ⁵ , G. F olatelli ¹ , T.-S. P YO 3 , Y. K ITAGAWA 4 , K. S. K AWABATA 5 , G. C. A NUPAMA 2 , T. K OZASA 6 ,
doi:10.1038/nature13558
Christa Call 1.1.2.3, Jens Hjorth², Darach Watson², Eli Dwek³, Justyn R. Maund².4, Ori Fox 5, Giorgos Leloudas 2.6, Daniele Malesani² & Avril C. Day-Jones7
Dust formed in the ejecta Pre-existing circumstellar dust The mass of newly formed dust increases with time? 500 868 50 100 150  239 1638 Time since peak (days) 5000 9000 Dust formation in the ejecta Dust formation in dense shell We should not discuss the mass of newly formed grains by integrating the formation of dust in the ejecta and CDS
At 615 and 714 day • dust mass: ~0.4 Msun • silicate-dominated Dwek & Arendt 2015, ApJ, 810, 75〇超新星ダスト研究における現在の二つの課題1)観測された大量のダストはいつ形成されたのか？ →中間赤外線と遠赤外線でのダスト量の違いを説明したい2)形成されるダストのサイズはどれくらいか？ →超新星による最終的なダスト放出量を明らかにしたい未解決の問題超新星イジェクタは、クランプ状になっている必要があるではどれくらい、クランプ状になっているか？ →輻射輸送だけでなく、形成するダストのサイズにも影響

O Presolar grains
-  discovered in meteorites -  showing peculiar isotopic compositions (highly different from the solar system's materials) -  thought to have originated in stars before the Sun was formed → offering key information on nuclear processes in the parent stars red giants, AGB stars, supernovae, novae ... -  mineral composition graphite, nanodiamond, TiC, SiC, Si3N4, Al2O3, MgAl2O4, TiO2, Mg2SiO4, MgSiO3 ... C (Nittler 2003) Al2O3 (Nittler+199)
O Oxygen isotopic composition of presolar oxide grains are believed to have been produced in the ejecta of SNe

O Evidence for Al2O3 formation in SNe
-  Infrared spectra of Cassiopeia A (Cas A) SNR → Al2O3 is one of the main grain species (Douvion et al. 2001; Rho et al. 2008)
O Dust formation calculations
-  the first condensate among oxide → sizes of Al2O3 grains : < ~0.03 µm (e.g., Nozawa+2003; Todini & Ferrara+2001)
grain radius (μm)
grain radius (μm)

Λon = Tsat/Tcoll : ratio of supersaturation timescale to gas collision timescale at the onset time (ton) of dust formation Λοη = Tsat/Tcoll ∞ Tcool Ngas • fcon,∞ and aave,∞ are uniquely determined by Λοη ## this is true for the formation of carbon and silicate grains
Nozawa+2015, ApJ, 811, L39 Λοη > 30,000 required → at least 10 times higher  gas density than those predicted by 1-D SN models Submicron-sized presolar Al2O3 grains identified as SN-origin were formed in dense clumps in the ejecta
Model of the calculation: MsN= (3 + 12) Msun, Eexp=1.8x10 51 erg, Nism =  1 cm-³
time (yr)
Nozawa+2015, ApJ, 811, L39 Evolution of dust in SNRs depends on the initial radii - Aini < 0.01 μm → completely destroyed - 0.02 μm < aini  < 0.1 μm → eroded in dense shell - aini > 0.1 μm → injected into the ISM We investigate the formation of Al2O3 grains for a variety of densities and cooling rates of the gas. 1) The average radius and condensation efficiency of newly formed Al2O3 grains are uniquely described by the non-dimensional quantity Λοη. 2) Presolar Al2O3 grains with radii above 0.25 μm can be formed only in the gas with more than 10 times higher density than those estimated by 1-D SN models. → indicating the presence of dense clumps in the SN ejecta 3) The measured sizes of presolar grains are powerful probes for constraining the physical conditions and structure in which they formed.

O Type Ia supernovae (SNe Ia)
-  thermonuclear explosion of a white dwarf (WD) - progenitor system:  (WD+MS) or (WD+WD)? -  discovered in all types of galaxies - star-forming, elliptical, irregular, etc ... -  used as cosmic standard candles Мв = mв - 5 log10(DL) - Aв - 5 → Rv = 1.0 ~ 2.5 (Rv = Av/(Ab − Av)） to minimize the dispersion of Hubble diagram (e.g., Tripp+1998; Conley+2007; Phillips+2013) cf. Rv = 3.1 for the average extinction curvei n the Milky-Way (MW)

O Other examples of Rv for SNe la
' average of ensembles of SNe la Rv = 1.0-2.3 -  from obtained colors of SNe la in near-UV to near-infrared (NIR) Rv ~ 3.2 (Folatelli+2010) Rv = 1.5-2.2 (e.g., Elisa-Rosa+2008; Kriscinuas+2007)
O Extinction in nearby galaxies
-  M 31 (Andromeda Galaxy) Rv = 2.1-3.1 (e.g., Melchior+2000; Dong+2014) -  elliptical galaxies Rv = 2.0-3.5 (Patil+2007) → Rv is moderately low or normal

O Type la SN 2014J
-  discovered in M 82 (D ~ 3.5±0.3 Mpc) - closest SN la in the last thirty years - highly reddened (Av ~ 2.0 mag) -  reddening law is reproduced by CCM relation with Rv ~ 1.5 (Ammanullah+2014; Foley+2014; Gao+2015)
1/λ (μm-1) ardelli, Clayton, Mathis 1989) Rv : ratio of total-to- selective extinction Rv = Av / E(B - V) = Av / (Ав – Аv) Α»/Av =  a(x) + b(x) / Rv where x = 1 / λ in our Galaxy Rv = 2.2-5.5 RV,ave ~ 3.1 - steeper extinction curve (lower Rv) → smaller grains - flatter extinction curve (higher Rv) → larger grains
- odd properties of interstellar dust (e.g., Kawabata+2014; Foley+2014) - multiple scattering by circumstellar dust (Wang 2005; Goobar 2008; Amanullah & Goobar 2011) If there is a thick dust shell, we must detect thermal dust emission as infrared echoes

O Near-infrared (NIR) observations
-  no excess flux at JHK bands -  IR echo model (thin shell approximation) constrain the mass of dust for a given position of the dust shell (Maeda, TN+2015) → conservative upper limits of optical depths in B band is TB < ~0.1
O Spitzer observations
-  no excess flux at 3.5/4.5 μm (Johansson+2015) -  upper limit of dust mass:  ~10~4 Msun → optical depth  T << 1
O MRN dust model (Mathis, Rumpl, & Nordsieck 1977) -  dust composition : silicate (MgFeSiO4) & graphite (C) -  size distribution   : power-law distribution n(a) ∞ a^{-q} with q=3.5, amax = 0.24 μm, amin = 0.005 μm Rv = 2.0 curve → amax = 0.129 µm, amin = 0.005 µm
Rv = 1.5 curve → amax = 0.0925 µm, amin = 0.005 µm Rv = 1.0 curve → amax = 0.057 µm, amin = 0.005 µm But, the values of Rv obtained from the MRN dust model are higher than Rv used for the CCM relation Rv,ссм = 1.5 curve → Rv, dust = 1.72 Rv,ссм = 1.0 curve → Rv, dust = 1.49 1) Many studies (mainly SNe la cosmology) suggest that the Rv values toward SNe la are very low (Rv ~ 1-2.5), compared with Rv = 3.1 in our Galaxy 2) Non-detection of IR echoes towards SNe la indicates that the Iow Rv is not due to the circumstellar dust but due to the interstellar dust in the host galaxies 3) The CCM curves with Rv = 1-2 can be reasonably fitted by the power-law dust model (graphite/astronomical silicate) with amax = 0.06-0.13 µm (instead of amax = 0.24 µm for Rv = 3.1)