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Ralf Siebenmorgen Köln 2012 ISM dust model Monte Carlo dust radiative transfer Proto-planetary disks: ring-like structures PAH destruction in proto-planetary disks Ralf Siebenmorgen, Frank Heymann, Nikolai Voshchinikov, Endrik Krűgel Peter Scicluna (PhD) Shadows, gaps and ring-like structures in proto-planetary disks
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Ralf Siebenmorgen Köln 2012 Si + aC : 60Å < a < 0.2-0.3µm ~ a -3.5 Graphite : 5Å < a < 80 Å ~ a -3.5 PAH : 30, 200 C ISM dust solar neighborhood Abundances [X/H in ppm]: 31Si + 150aC + 50gr + 30PAH
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Ralf Siebenmorgen Köln 2012 PAH absorption cross section +2200 bump Malloci et al. (2007) Verstraete et al. 1992
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Ralf Siebenmorgen Köln 2012 Siebenmorgen et al. (2001,2007) Nucleus of NGC1808 PAH emission cross section starbursts
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Ralf Siebenmorgen Köln 2012 Linear polarisation Serkowski ~ Voshchinnikov (2012)
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Ralf Siebenmorgen Köln 2012 Extinction: Prolate/ Sphere
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Ralf Siebenmorgen Köln 2012 ISM dust Fitzpatrick (99)
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Ralf Siebenmorgen Köln 2012 NGC2023 HD37903 Dust model : - Extinction - Emission - Polarisation 8μm Peeters et al. 2012
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Ralf Siebenmorgen Köln 2012 Albedo Extinction
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Ralf Siebenmorgen Köln 2012 Emission
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Ralf Siebenmorgen Köln 2012 Polarisation
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Ralf Siebenmorgen Köln 2012 Circular polarisation of dust: oblate versus prolate ~maximum of linear polarisation x ~Voshchinnikov (2002, 2012)
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Ralf Siebenmorgen Köln 2012 ISM Krügel&Siebenmorgen (1994) Homogenous versus composite grains
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Ralf Siebenmorgen Köln 2012 Arbitrary dust distribution Pseudo adaptive mesh 1.geometry 3D Monte Carlo Radiative Transfer
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Ralf Siebenmorgen Köln 2012 1.geometry 2.source Source emits photon packages of equal energy Monte Carlo
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Ralf Siebenmorgen Köln 2012 1. geometry 2. source 3. inter-action 4. dust temperature absorption / scattering / no interaction Monte Carlo = - ln( ζ)
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Ralf Siebenmorgen Köln 2012 Photons escape model cloud Monte Carlo 1. geometry 2. source 3. inter-action 4. temperature 5. detection 6. Lightechos: time as 4 th dimension?
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Ralf Siebenmorgen Köln 2012 Multiple photons at a time: vectorized MC 100 x faster Challenges: Cell locked when hit by photon Parallel random number generator (Mersene Twister) Graphical Processing Units (CUDA) Heymann & Siebenmorgen (2012)
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Ralf Siebenmorgen Köln 2012 K06 : Krügel (2006) Dusty : Iveciz et al. (1999 ) Dust sphere: A V = 1000mag, heated by star Comparison of 2 ray tracing codes
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Ralf Siebenmorgen Köln 2012 Sphere T * = 2500K ρ (r) = const. A V =10 1 1001000 mag ~5% for 0 MC versus benchmark Heymann & Siebenmorgen (2012)
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Ralf Siebenmorgen Köln 2012 Method ParallelizationAdvantage Time Benchmark sphere τ~1000) Lucy YES (but floating) Optical thin>1h Bjorkman & Wood Partly (not independent) No iteration5min ourYESGPU<1min MC methods Heymann & Siebenmorgen (2012)
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Ralf Siebenmorgen Köln 2012 3D proto-planetary disk + spiral MHD (Fargo) density T * = 5800K L * = L sun A v =10mag 8au 3au
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Ralf Siebenmorgen Köln 2012 ELT 42m PAH imaging
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Ralf Siebenmorgen Köln 2012 D = 50pc 50mas at 11.3μm PSF dual band + coronograph ELT 42m PAH imaging
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Ralf Siebenmorgen Köln 2012 D = 50pc 50mas at 11.3μm MIR imaging gap /px (μJy /px)
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Ralf Siebenmorgen Köln 2012 Shadows in planet forming disks Gaps and ring-like structures:... are caused by hydrostatic + radiation balance without the need to postulate a companion/planet (Siebenmorgen & Heymann, 2012). PAH emission from disks: Low / high detection statistics of PAH in T Tauri / Herbig Ae stars is consistent with X-ray destruction of PAH (Siebenmorgen & Kr ű gel 2010).
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Ralf Siebenmorgen Köln 2012 Armitage07 Lagrange et al, β Pic planet detection, Science10: …validates the use of disk structures as fingerprints of embedded planets. Gaps and ring-like structures in hydro-dynamical simulations
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Ralf Siebenmorgen Köln 2012 Radiative transfer 1D slab geometry ?
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Ralf Siebenmorgen Köln 2012 Puffed up inner rim Dullemond et al.2001 Kama et al. 2010 Shadow T mid - lower
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Ralf Siebenmorgen Köln 2012 Puffed up second rim T mid - warmer Shadow T mid - lower
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Ralf Siebenmorgen Köln 2012 Puffed up third rim
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Ralf Siebenmorgen Köln 2012 0) II) Hydrostatic and radiation balance I)T(x,y,z) by MC
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Ralf Siebenmorgen Köln 2012 Proto-planetary disk models
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Ralf Siebenmorgen Köln 2012 T Tauri disk
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Ralf Siebenmorgen Köln 2012 Gaps and ring-like structures without planet extinction layer (photosphere) τ (z bot ) :=1
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Ralf Siebenmorgen Köln 2012 Gaps and ring-like structures in the mid-IR emission
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Ralf Siebenmorgen Köln 2012 Gaps and ring-like structures in scattered light
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Ralf Siebenmorgen Köln 2012 PAH detection statistics PAH excitation / destruction PAH emission from disks
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Ralf Siebenmorgen Köln 2012 PAH in a mono-energetic heating bath if | U f – U i – hν | < ½ ΔU f : A fi = K ν F ν / hν Siebenmorgen & Krűgel (2010) PAH emission from disks
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Ralf Siebenmorgen Köln 2012 store PAH absorption events of each cell compute PAH emission neglect PAH self absorption Monte Carlo + PAH PAH emission from disks
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Ralf Siebenmorgen Shadows in planet forming disks PAH emission from disks MC versus benchmark
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Ralf Siebenmorgen Shadows in planet forming disks EoEo PAH destruction Unimolecular dissociation 1) single hard photon : independent of distance 2) many soft photons : ~AU Arrhenius form: t dis ~ exp(E o /kT) / ν 0 « t cool ~ 1s T min = E o /k ln(ν 0 ) ~2000K; E o ~ 5eV; ν 0 = 10 13 Hz ΔE = 3N c kT min ~ 0.1 N c. E b => N c < 2 ΔE / [eV] PAH unstable Siebenmorgen & Kr ű gel (2010) T [K] time t cool t abs ~ 1h
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Ralf Siebenmorgen Shadows in planet forming disks Stationary disk Sufficient X-ray photons? α τ = 1 z I } # C in PAH # hard γ absorption/sec PAH removal time << T Tauri pahse top extinction layer Σ = α/κ = h ν 4 π r 2 /Lκ
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Ralf Siebenmorgen Shadows in planet forming disks Vertical mixing /v = t exp > t dis Disk lifetime => PAH replenishment Siebenmorgen & Krűgel (2010)
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Ralf Siebenmorgen Shadows in planet forming disks PAH emission from disks T Tauri PAH emission from disks
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Ralf Siebenmorgen Shadows in planet forming disks Mid-IR emission from Herbig disks Siebenmorgen & Heymann (2012)
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Ralf Siebenmorgen Shadows in planet forming disks Shadows in planet forming disks Dust model for: extinction, emission, linear and circular polarisation Gaps and ring-like structures:... are caused by hydrostatic + radiation balance without the need to postulate a companion/planet (Siebenmorgen&Heymann, 2012). PAH emission from disks: Low / high detection statistics of PAH in T Tauri / Herbig Ae stars is consistent with X-ray destruction of PAH (Siebenmorgen & Kr ű gel 2010).
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Ralf Siebenmorgen Köln 2012 PAH band ratios: ionisation dehydrogenation PAH emission from disks Galiano et al.08
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