1. Background Last review on disk chemistry in Protostars and Planets: Prinn (1993) Kinetic Inhibition model - (thermo-)chemical timescale vs (radial) mixing timescale - constraints and goals … composition of solar system materials Spectroscopic observation of disks in mm, sub-mm, infrared e.g. Dutrey et al., Najita et al. Detailed models of disk structure e.g. Dullemond et al. Since then…

2. Outline General Theoretical Picture - disk structure - key ingredients: UV, X-ray, Cosmic-ray Observations - mm & sub-mm - infrared Chemical-Physical Likns - thermal structure - grain evolution - ionization degree - mixing Deuterium Chemistry and Comets Future

3. General Theoretical Picture three-layer model (i) photon-dominant layer UV & X-ray irradiation low density (n H < 10 5 cm -3 ) high temperature (T > several 10 K) -4 -6 -8 -10 -12 log n(i)/n H height from midplane [AU] 0100200300400 vertical distribution @ r  300 AU Aikawa & Herbst (1999) Willacy & Langer (2000) Aikawa et al. (2002) van Zadelhoff et al. (2003)

4. General Theoretical Picture three-layer model (i) photon-dominant layer UV & X-ray irradiation low density (n H < 10 5 cm -3 ) high temperature (T > several 10 K) (ii) warm molecular layer high density (n H > 10 5 cm -3 ) moderate temperature (T > 20 K) -4 -6 -8 -10 -12 log n(i)/n H height from midplane [AU] 0100200300400 vertical distribution @ r  300 AU Aikawa & Herbst (1999) Willacy & Langer (2000) Aikawa et al. (2002) van Zadelhoff et al. (2003)

5. General Theoretical Picture three-layer model (i) photon-dominant layer UV & X-ray irradiation low density (n H < 10 5 cm -3 ) high temperature (T > several 10 K) (ii) warm molecular layer high density (n H > 10 5 cm -3 ) moderate temperature (T > 20 K) (iii) midplane freeze-out layer very high density (n H > 10 7 cm -3 ) low temperature (T < 20 K) -4 -6 -8 -10 -12 log n(i)/n H height from midplane [AU] 0100200300400 vertical distribution @ r  300 AU cf. Observation (Dutrey et al. 1997) : - high CN/HCN ratio - low abundance of gaseous molecules Aikawa & Herbst (1999) Willacy & Langer (2000) Aikawa et al. (2002) van Zadelhoff et al. (2003)

6. General Theoretical Picture three-layer model (i) photon-dominant layer UV & X-ray irradiation low density (n H < 10 5 cm -3 ) high temperature (T > several 10 K) (ii) warm molecular layer high density (n H > 10 5 cm -3 ) moderate temperature (T > 20 K) (iii) midplane freeze-out layer very high density (n H > 10 7 cm -3 ) low temperature (T < 20 K) (iv) inside snow line (r < 10 AU) thermal desorption “hot core” like chemistry (Najita et al. talk; Markwick et al. 2002; Ilgner et al. 2004) -4 -6 -8 -10 -12 log n(i)/n H height from midplane [AU] 0100200300400 vertical distribution @ r  300 AU Aikawa & Herbst (1999) Willacy & Langer (2000) Aikawa et al. (2002) van Zadelhoff et al. (2003)

7. Key ingredients X-rays from central star excite molecules (Tine et al. 1997) ionization (Glassgold et al. 1997) induce UV photons (Bergin et al. 2005) non-thermal desorption (Najita et al. 2001) enhance HCN, CN, HCO + (Aikawa & Herbst 1999; 2001;Markwick et al. 2002) X-ray induced UV ? wavelength (Å) F (erg cm -2 s -1 Å -1 ) height from midplane [AU] ionization rate [s -1 ] 10 -15 10 -16 r=700AU Lx=10 31 erg/s 10 30 erg/s 10 29 erg/s 10 28 erg/s

8. Key ingredients enhance HCN, CN, HCO + (Aikawa & Herbst 1999; 2001;Markwick et al. 2002) X-ray local hot spot grain aggregate ejected molecules height from midplane [AU] log n(i)/n H -7 -11 -5 -9 -13 0 20406080 CO CN HCN X-ray desorption only thermal X-rays from central star excite molecules (Tine et al. 1997) ionization (Glassgold et al. 1997) induce UV photons (Bergin et al. 2005) non-thermal desorption (Najita et al. 2001)

9. Key ingredients Cosmic-rays ionization … driving force for chemistry in molecular clouds - attenuation length 96 g cm -2 (Umebayashi & Nakano 1981) - scattered by magnetic field ?? non-thermal desorption

10. Key ingredients interstellar UV stellar UV scattering 1+1D 2D scatter height from midplane [AU] log n(i)/n H -4 -6 -8 -10 -12 -6 -8 -10 -12 UV from central star and interstellar field photo-dissociation and ionization - require 2D radiation transfer with scattering (van Zadelhoff et al. 2003 ) - contribution of Lya line (Bergin et al. 2003; 2006) photo-desorption

11. Key ingredients UV from central star and interstellar field photo-dissociation and ionization - require 2D radiation transfer with scattering (van Zadelhoff et al. 2003 ) - contribution of Lya line (Bergin et al. 2003; 2006) photo-desorption 0 -2 -4 Log 10 F (at 100 AU) (erg cm -2 s -1 Å -1 ) C III Ly  1250 wavelength (Å) 1200 CO H2O strong L  weak L  height from midplane [AU] log n(i)/n H -4 -6 -8 -5 -7 -9

12. Observation Gas-Phase radio: - neutral: H 2, CO, CN, HCN, CS, H 2 CO, C 2 H, - ion: HCO +, N 2 H +, H 2 D +, - deuterated: HDO, H 2 D +, DCN mid-IR: C 2 H 2, HCN, CO 2 NIR: CO, H 2 O ( Najita et al.) Optical: OI Detected species: Solid amorphous & crystalline silicates (Wooden et al.) PAH Ice water, CO, CO 2, NH 4 + Dutrey et al. (1997), IRAM 30m - trace r > several 10 AU - high CN/HCN ratio - low abundance of gaseous molecules Sigle Dish

13. Observation Gas-Phase radio: - neutral: H 2, CO, CN, HCN, CS, H 2 CO, C 2 H, - ion: HCO +, N 2 H +, H 2 D +, - deuterated: HDO, H 2 D +, DCN mid-IR: C 2 H 2, HCN, CO 2 NIR: CO, H 2 O ( Najita et al.) Optical: OI Detected species: Solid amorphous & crystalline silicates (Wooden et al.) PAH Ice water, CO, CO 2, NH 4 + N T (CS) = 10 13 -10 14 cm -2 Upper limits only for H 2 S,SO,SO 2 CS dominant Interferometer -less dilution - imaging

14. Observation Gas-Phase radio: - neutral: H 2, CO, CN, HCN, CS, H 2 CO, C 2 H, - ion: HCO +, N 2 H +, H 2 D +, - deuterated: HDO, H 2 D +, DCN mid-IR: C 2 H 2, HCN, CO 2 NIR: CO, H 2 O ( Najita et al.) Optical: OI Detected species: Lahuis et al. (2006), Spitzer - T > 300 K - r << 100 AU - n(i)/n H =10 -6 -10 -5 cf. Markwick et al. (2001) Solid amorphous & crystalline silicates (Wooden et al.) PAH Ice water, CO, CO 2, NH 4 +

15. Observation Gas-Phase radio: - neutral: H 2, CO, CN, HCN, CS, H 2 CO, C 2 H, - ion: HCO +, N 2 H +, H 2 D +, - deuterated: HDO, H 2 D +, DCN mid-IR: C 2 H 2, HCN, CO 2 NIR: CO, H 2 O ( Najita et al.) Optical: OI Detected species: Solid amorphous & crystalline silicates (Wooden et al.) PAH Ice water, CO, CO 2, NH 4 + Acke et al. (2005) - traces disk surface at r < 1AU  double-peak  disk rotation

16. Observation Gas-Phase radio: - neutral: H 2, CO, CN, HCN, CS, H 2 CO, C 2 H, - ion: HCO +, N 2 H +, H 2 D +, - deuterated: HDO, H 2 D +, DCN mid-IR: C 2 H 2, HCN, CO 2 NIR: CO, H 2 O ( Najita et al.) Optical: OI Detected species: Solid amorphous & crystalline silicates (Wooden et al.) PAH Ice water, CO, CO 2, NH 4 + LkHa330 PHA Silicate Geers et al. (2006) - r = 10-100 AU - in 50% of Herbig Ae 15 % of T Tauri stars  long timescale for settling and growth

17. Observation Gas-Phase radio: - neutral: H 2, CO, CN, HCN, CS, H 2 CO, C 2 H, - ion: HCO +, N 2 H +, H 2 D +, - deuterated: HDO, H 2 D +, DCN mid-IR: C 2 H 2, HCN, CO 2 NIR: CO, H 2 O ( Najita et al.) Optical: OI Detected species: Solid amorphous & crystalline silicates (Wooden et al.) PAH Ice H 2 O, CO, CO 2, NH 4 + Pontoppidan et al. (2005) edge-on disk - ice absorption bands against scattered light and warm dust emission - upto 50 % of CO 2 and H 2 O are in disk

18. T gas and T dust are not necessarily equal. heating cooling dust radiation from thermal radiation star or upper layer gas UV (photo-electric) lines (C+, CI, OI …) gas-dust collision gas-dust collision - energy balance and chemistry have be solved simultaneously -T gas > T dust at the surface layer  extended disk “atmosphere” - no hot finger (?)  Self-consistent calc of T gas, T dust, and density distribution (Nomura & Millar 2005) - density distribution is determined by Tgas Chemical-Physical Links: gas thermal structure (Dullemond et al.; Inga & Dullemond 2004; Junkheid et al. 2004)

19. Chemical-Physical Links: Grain Growth Grains must coagulate & sediment to make planets - calculation of coagulation equation (Weidenschiling@PPII, Dullemond & Dominik 2005, Tanaka et al. 2005) - SEDs and disk images are better reproduced with a max 1 mm (Miyake & Nakagawa 1995; D’Alessio et al. 2001; Chiang et al. 2001)  dust opacity decreases at UV wavelength >  D’Alessio et al. (2001) ISM dust a max =1mm

20. Chemical-Physical Links: Grain Growth As dust grows… - UV penetrates deeper into the disk  T @ intermediate height increases - Photoelectric heating becomes less efficient  T @ disk surface decreases  disk is less flared-up - Molecular layer is pushed down to lower heights Junkheid et al. (2004) Aikawa & Nomura (2006)

21. Chemical-Physical Links: ion fraction Angular momentum transport by Magneto-Rotational Instability - magnetic field decouples if ionization degree (x e ) is too low - accretion and turbulence may be active only on disk surface Gammie (1996)

22. photoionization of H: x e > 10 4 photoionization of C: x e  10 4 Cosmic-ray and X-ray ionization: x e  10 -11 - 10 -6 HCO +, H 3 + Cosmic-ray and Radionucleide: r 60 AU x e  10 -12 x e  10 -12 x e  10 -11 Metal + /grain HCO + /grain H 3 + & D 3 + (Sano et al. 2000; Semenov et al. 2004) agreement with simple chemistry ?? -> TED Chemical-Physical Links: ion fraction Angular momentum transport by Magneto-Rotational Instability - magnetic field decouples if ionization degree (x e ) is too low - accretion and turbulence may be active only on disk surface

23. Chemical-Physical Links: mixing Three must be some mixing in the disks, because… - angular mom. transport by turbulent viscosity - crystalline silicate in disks and comets - refractory inclusions in meteorites t mix ~ t vis ? (cf. Carballido et al. 2005) Chemistry is modified if t mix < t chem : Three-layer structure is preserved because t chem is small in the surface and midplane Species formed on grains (ex. H 2 CO) are enhanced by vertical mixing Ionization fraction is not modified 10100 NH 3 CS R [AU] Stationary z-mixing Advection & r-mixing H 2 CO electron Semenov et al. (2006) in prep Z/Z max 0.1 1.0 see also Willay et al. and Ilgner et al.

24. Deuterium chemistry in disks Isotopic fractionations in comets and meteorites D/H enrichment in low temperature - D-H exchange reactions H 3 + + HD  H 2 D + + H 2 + 230K H 2 D + + CO  HCO + + HD H 2 D + + e  H 2 + D - Further enhancement by CO depletion survival of interstellar matter ? nebula process ?

25. Deuterium chemistry in disks Detection of deuterated species in disks ! species col [cm -2 ] D/H object DCO + 3x10 11 0.035 TW Hya HDO (0.064) LkCa15 8x10 12 (1x10 -3 ) DM Tau DCN (< 2x10 -3 ) LkCa15 o-H 2 D + 4x10 12 DM Tau 6x10 13 TW Hya van Dishoeck et al. (2003), Kessler et al. (2003), Caccarelli. et al. (2004; 2005), DM Tau HDO H2D+H2D+ TW Hya

26. Deuterium chemistry in disks species col [cm -2 ] D/H object DCO + 3x10 11 0.035 TW Hya HDO (0.064) LkCa15 8x10 12 (1x10 -3 ) DM Tau DCN (< 2x10 -3 ) LkCa15 o-H 2 D + 4x10 12 DM Tau 6x10 13 TW Hya van Dishoeck et al. (2003), Kessler et al. (2003), Caccarelli. et al. (2004; 2005), Model: - High D/H right above the midplane - Midplane is traced by H 3 +, H 2 D +, HD 2 +, D 3 +  grain size & ionization rate Ceccarelli & Dominik (2005) Detection of deuterated species in disks !

27. Deuterium Chemistry: Links to Comets Comet: ice @ r= 5-30 AU cf. radio obs: gas beam size > 100 AU D/H in comets HDO 3x10-4 (2x10-3) DCN 2x10-3 -D/H changes while fluid parcel migrates towards the inner radius (Aikawa & Herbst 1999) … mixing is not considered - D/H is determined by radial mixing (Hersant et al. 2001) … only thermal reactions D/H model with mixing (radial & vertical) and full chemistry is highly desirable ! species col [cm -2 ] D/H object DCO + 3x10 11 0.035 TW Hya HDO (0.064) LkCa15 8x10 12 (1x10 -3 ) DM Tau DCN (< 2x10 -3 ) LkCa15 o-H 2 D + 4x10 12 DM Tau 6x10 13 TW Hya

28. future