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Inga Kamp The role of the central star for the structure of protoplanetary disks

Inga Kamp The role of the central star for the structure of protoplanetary disks Peter Woitke, Wing-Fai Thi, Ian Tilling (all Edinburgh). Protoplanetary Disks and Planet Formation. Dust dynamics are controlled by gas, even at late times ! dust substructure dust coagulation dust settling.

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Inga Kamp The role of the central star for the structure of protoplanetary disks

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  1. Inga Kamp The role of the central star for the structure of protoplanetary disks Peter Woitke, Wing-Fai Thi, Ian Tilling (all Edinburgh)

  2. Protoplanetary Disks and Planet Formation • Dust dynamics are controlled by gas, even at late times ! • dust substructure • dust coagulation • dust settling [Reverse ∂p/∂r at 70 AU Klahr & Lin 2001] [HR4796: NICMOS 1.6 mm Schneider et al. 1999] 8 Myr mJy/pixel [Barge & Sommeria 1995, Johansen et al. 2006, 2007]

  3. Outline • Various planet forming environments (BD - T Tauri - Herbig) • Second generation disk structure modeling • How do observations inform us about the star-disk interaction ?

  4. Outline • Various planet forming environments (BD - T Tauri - Herbig) • Second generation disk structure modeling • How do observations inform us about the star-disk interaction ?

  5. Outline • Various planet forming environments (BD - T Tauri - Herbig) • Second generation disk structure modeling • How do observations inform us about the star-disk interaction ?

  6. Protoplanetary Disk Models Key astrophysical questions: • What is the environment in which planets form ? disk structure - boundary conditions for planet formation • Can planets form around stars different from our Sun ? star-disk interaction - impact on disk structure and dispersal

  7. Outline • Various planet forming environments (BD - T Tauri - Herbig) • Second generation disk structure modeling • How do observations inform us about the star-disk interaction ?

  8. Disk properties Dust in BD disks evolves on same time scale as T Tauri disks Inner disk clearing occurs much faster in T Tauri disks Dust models fit BD, T Tauri and Herbig SEDs in the same way indicating the first steps of planetesimal formation in all cases some BD SEDs require flaring disks, others flat… low # statistics [2 BDs @ 2 and 10 Myr: Sterzik et al. 2004] [8m excess @ 5 Myr: Carpenter et al. 2006] [Pascucci et al. 2003, Allers et al. 2006, Bouy et al. 2008]

  9. Disk properties [Kessler-Silacci et al. 2007] [Pascucci et al. 2009] lower HCN/H2C2 ratios in the disks around brown dwarfs weaker and more processed silicate features

  10. Outline • Various planet forming environments (BD - T Tauri - Herbig) • Second generation disk structure modeling • How do observations inform us about the star-disk interaction ?

  11. Protoplanetary Disk Models physical structure radiative transfer comparison with observation chemical composition

  12. Protoplanetary Disk Models surface density  = 0 (r/r0)-p dust temperature T = T0 (r/r0)-q disk scale height H = H0 (r/r0)-e physical structure radiative transfer comparison with observation chemical composition [e.g. Menard et al.; Pinte et al. 2006]

  13. Protoplanetary Disk Models surface density  = 0 (r/r0)-p dust temperature 2D continuum RT disk scale height H = (cs2 r3/GM*)0.5 physical structure radiative transfer comparison with observation chemical composition [e.g. D’Alessio et al. 1998, Dullemond et al. 2002] Gas chemical modeling on top of fixed density structure [e.g. Aikawa et al. 2002, Semenov et al. 2008]

  14. Protoplanetary Disk Models physical structure hot flaring surface line radiative transfer comparison with observation chemical composition cold midplane molecule freeze-out rich molecular chemistry atomic/ionized [e.g. Aikawa et al. 2002, Kamp & Dullemond 2004] [PPV chapters: Dullemond et al. 2007, Bergin et al. 2007]

  15. Protoplanetary Disk Models ProDiMo physical structure radiative transfer comparison with observation chemical composition [Woitke, Kamp, Thi 2009] Similar approaches have been followed by other groups [Nomura & Millar 2005, Gorti & Hollenbach 2004, 2008]

  16. Chemistry stationary solution with modified Newton-Raphson algorithm (switch to time-dependant) 65 species: H, H+, H-, H2, H2+, H3+ He, He+ C, C+, CO, CO+, CO2, CO2+, HCO, HCO+, H2CO CH, CH+, CH2, CH2+, CH3, CH3+, CH4, CH4+, CH5+ O, O+, O2, O2+, OH, OH+ H2O, H2O+, H3O+ N, N+, NH, NH+, NH2, NH2+, NH3, NH3+, N2, HN2+ CN, CN+, HCN, HCN+, NO, NO+ Si, Si+, SiH, SiH+, SiO, SiO+, SiH2+, SiOH+ S, S+, Mg, Mg+, Fe, Fe+ --> plus CO, H2O, CO2, CH4, NH3 ice

  17. Heating and cooling Heating photo-electric heating, PAH heating, viscous (α) heating, cosmic ray, C photo-ionisation, coll. de-excitation of H⋆2 , H2 on grains, H2 photodissociation, IR background line heating thermal accomodation on grains, OI, CII, CI fine-structure cooling, CO ro-vibrational (110 levels, 243 lines), o/p H2O rotational (45/45 levels, 258/257 lines), o/p H2 quadrupole (80/80 levels, 803/736 lines), SiII, SII, FeII semi-forbidden (80 levels, 477 lines), Ly α, MgII h&k, OI 6300Å Cooling

  18. Heating and cooling Heating photo-electric heating, PAH heating, viscous (α) heating, cosmic ray, C photo-ionisation, coll. de-excitation of H⋆2 , H2 on grains, H2 photodissociation, IR background line heating, (X-ray heating) thermal accomodation on grains, OI, CII, CI fine-structure cooling, CO ro-vibrational (110 levels, 243 lines), o/p H2O rotational (45/45 levels, 258/257 lines), o/p H2 quadrupole (80/80 levels, 803/736 lines), SiII, SII, FeII semi-forbidden (80 levels, 477 lines), Ly α, MgII h&k, OI 6300Å Cooling

  19. Protoplanetary Disk Models interstellar UV stellar UV stellar X rays soft inner and outer edges [Hartmann et al. 1989, Hughes et al. 2008, Woitke, Kamp & Thi 2009]

  20. The Thermal Balance Photoelectric heating of the gas e- stellar photons small grains: a << l (e.g. PAHs) yield ~ ?? e- e- e- large grains: a >> l (micron sized) yield ??

  21. The Thermal Balance Photoelectric heating of the gas e- stellar photons small grains: a << l (e.g. PAHs) yield ~ ?? e- e- e- large grains: a >> l (micron sized) yield ?? [Abbas et al. 2006]

  22. Impact of UV Irradiation HD104237 H2 OVI H2, CO photodissociation C ionization FUSE: Apr 2000 STIS: Oct 2001 May 2001 GHRS: Nov 1994

  23. Impact of UV Irradiation UV excess time 5000 K 10 50 80 500

  24. Impact of UV Irradiation UV excess time 0 log n(OH)/n(tot) -14 -5 -10

  25. Protoplanetary Disk Models interstellar UV stellar UV stellar X rays soft inner and outer edges [Hartmann et al. 1989, Hughes et al. 2008, Woitke, Kamp & Thi 2009]

  26. The Thermal Balance TW Hya LX ~ 1030 erg/s [Kastner et al. 1997] [Nomura et al. 2007] X-ray heating of the gas Primary ionization stellar X-rays e- 124.0 Å 1.24 Å * e- Secondary ionization * e- Auger electrons [Glassgold et al. 2004, Meijerink et al. 2008]

  27. Protoplanetary Disk Models Flaring disk structure “early Sun” M* = 1 M L* = 1 L Teff = 5800 K Mdisk = 10-2 M 0.5-500 AU dust: 90% Mg2SiO4 10% Fe 0.1-10 m (2.5) [Woitke, Kamp, Thi 2009] X-ray source @ 20 R to irradiate disk midplane

  28. Protoplanetary Disk Models Flaring disk structure “Herbig star” M* = 2.2 M L* = 32 L Teff = 8500 K Mdisk = 10-2 M 0.5-500 AU dust: 90% Mg2SiO4 10% Fe 0.1-10 m (2.5) T Tauri Herbig Ae

  29. Protoplanetary Disk Models Herbig Ae T Tauri decreasing disk mass Flaring disk structure “Herbig star” M* = 2.2 M dust: L* = 32 L 90% Mg2SiO4 Teff = 8500 K 10% Fe Mdisk = 10-2, 10-3, 10-4 M 0.05-200 m (3.5) 0.5-700 AU self-similarity

  30. Outline • Various planet forming environments (BD - T Tauri - Herbig) • Second generation disk structure modeling • How do observations inform us about the star-disk interaction ?

  31. Probes of UV Irradiation: [OI], OH OH photodissociation layer: OH + n O* + H O* denotes the 1D2 excited level (decay emits a 6300 Å photon) 460 AU WFPC2 [Bally et al. 2000, Störzer & Hollenbach 1998, Acke et al. 2005] [Mandell et al. 2008, Salyk et al. 2008]

  32. Probes of UV Irradiation: [OI], OH OH photodissociation layer: OH + n O* + H O* denotes the 1D2 excited level (decay emits a 6300 Å photon) VLT/UVES: HD97048 normalized flux velocity [km/s] [Bally et al. 2000, Störzer & Hollenbach 1998, Acke et al. 2005] [Mandell et al. 2008, Salyk et al. 2008]

  33. Probes of UV, X-ray Irradiation: CO, H2 Fluorescence excitation vs. thermal emission: CO UV pumping of electronic states => cascade into high v levels H2 UV (Lyman & Werner bands) or X-rays (collisions with fast e-) [v=1-0 S(1), S(0), v=2-1 S(1) NIR: Carmona et al. 2008] [Brittain et al. 2007] see talkby Gerrit van der Plas

  34. Probes of UV, X-ray Irradiation: CO, H2 Fluorescence excitation vs. thermal emission: CO UV pumping of electronic states => cascade into high v levels H2 UV (Lyman & Werner bands) or X-rays (collisions with fast e-) [Brittain et al. 2007] see talkby Gerrit van der Plas [S(1), S(2), S(4) pure rotational MIR lines: Bitner et al. 2008]

  35. Probes of X-ray Irradiation: NeII see talk by Richard Alexander [Glassgold et a. 2007, Pascucci et al. 2007, Lahuis et al. 2007, Meijerink et al. 2008]

  36. Probes of gas-dust decoupling C H [Pietu et al. 2007] D E 0 50 100 150 200 R (AU) temperatures derived from gas lines at the surface are higher than dust temperatures => support for decoupling of gas and dust in the surface layers D: 13CO 3-2 E: 13CO 1-0 C: 12CO 2-1 H: HCO+ 4-5 [van Zadelhoff et al. 2001]

  37. Probes of gas-dust decoupling [OI] emission MIR dust emission [Fedele et al. 2008] dust is flat (self-shadowed) and gas is flaring => support for decoupling of gas and dust in the surface layers

  38. GASPS: A Herschel Key program GAS evolution in Protoplanetary Systems (PI: Dent) ~200 disks distributed over spectral type, age, and disk mass [CII], [OI], CO and H2O lines Aim: probe the gas mass evolution throughout the planet forming phase

  39. GASPS: A Herschel Key program physical structure line radiative transfer comparison with observation chemical composition Monte Carlo line radiative transfer understand where the line originates and then put resolution there !! [Hogerheijde, van der Tak 2000] Kamp, Tilling, Woitke, Thi, Hogerheijde

  40. Key points to take home • Models predict that stellar UV and X-ray radiation shape the disk structure and chemistry and we actually observe that ! • Individual gas lines DO NOT probe total disk mass ! but we keep trying with multiple tracers … • Gas lines DO probe the physical and chemical conditions in the region where they arise (interplay between radiative transfer and chemical structure) and we try hard with GASPS to find the desperately wanted 10-4 M disks…

  41. Thank You !

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