Thomas Henning and Dima Semenov

1. Courtesy of David E. Trilling Thomas Henning and Dima Semenov Max-Planck-Institut für Astronomie, Heidelberg _______________ Chemistry and Dynamics in Protoplanetary Disks _______________

2. Motivation • Initial conditions for planet formation • Chemical composition of primitive bodies in the solar system • Gas depletion and dissipation in disks – Molecules as tracers of disk history • Chemistry – Physical state of the disk (temperature, density, radiation, ionization, transport)

3. Any Hot Topics? • Coupling between dynamics and chemistry • Complete evolutionary track from cold cores to disks (e.g. deuteration sequence) • Coupling between solid-phase and gas-phase disk components (grain evolution and settling) • Early stellar activity (winds, X-rays, UV, …)

4. Observable region with interferometers ~1000 AU IS UV, cosmic rays hν, UV, X-rays photon-dominated layer snowline warm mol. layer 0 cold midplane accretion (magneto- rotational instability) turbulent mixing wind 1 AU 100 AU ~500 AU Disk Structure

5. Highly Dynamical Environment 3.5 - 6.5 AU (#51) -7 ° - 7 ° (#20) ΩK = 12 Flux limited RT Klahr, Henning, and Kley (1999) Disk Physics __________ __________

6. MRI Overview slower rotation faster rotation Rotational axis Magnetic field geometry centrifugal force & magnetic tension  loop generation (turbulence) __________ N. Dziourkevitch & H. Klahr (2006), ApJ, in prep. __________

7. Ionization Structure of a Disk: Effect of Grain Evolution __________ __________

8. Ionization Structure of a Disk: Effect of Grain Evolution „Layered“ vertical structure __________ Semenov, Wiebe, Henning (2004) __________

9. N2H+ in disks: CID Collaboration (Bordeaux – Heidelberg – Jena – Grenoble - Paris) __________ N2H+/HCO+ ~ 0.03 HCO+ is dominant ion N2H+ is not a good tracer of ionization 1012 10 1010 Dutrey, Henning et al. (2006), A&A, submitted __________

10. Dynamics and Chemistry __________ Chemically reacting flow system „Well-mixed reactor system“ Flow along predominant direction including mixing __________

11. Observational Evidence • Non-thermal line broadening (~100 m/s) • Crystalline silicates in comets and disks (van Boekel et al. 2005, Crovisier et al. 1997, Wooden et al. 2005) • Chondritic refractory inclusions in meteorites (MacPherson et al. 1988) • Gas-phase CO at T<25K in DM Tau (Dartois et al. 2003) __________

12. CS CS no vertical mixing vertical mixing Steady Inner Disk Model __________ Ilgner, Henning et al. (2004) __________

13. Previous Studies __________ • Gail & Tscharnuter (>2000): 2D hydro + RT inner disk, gas-phase combustion chemistry, grain evolution  crystalline silicate distribution, carbon chains • Ilgner et al. (2004; 2006a,b): 1+1D inner disk, 1D vertical mixing & radial transport, gas-grain chemistry  molecular abundances • Lyons & Young (2005): inner solar nebula, 1D vertical mixing, photochemistry  16/18 oxygen isotopic anomalies • Willacy et al. (2006): 1+1D outer disk, 1D vertical chemistry, gas-grain + surface chemistry  molecular abundances __________

14. Chemistry with Dynamics __________ Input: • Physical conditions, diffusion coefficient & flow data Initial abundances of species • A chemical network • A numerical solver • Benchmarking Evolution = Formation - Destruction + Diffusion - Advection [ Chemistry ] [ Dynamics ] __________

15. Chemistry with Mixing __________ • 2D-implicit scheme for chemistry with mixing • Fickian diffusion • Full/reduced chemical networks • 1D-benchmarking with K. Willacy & D. Wiebe t~N3(amount of species in the model) Semenov , Wiebe, & Henning (2006), ApJL, submitted __________

16. Disk Model __________ • 1+1D flared disk (D‘Alessio et al. 1999) • Mdisk= 0.05M, Mdot = 10-8M/yr, M = 0.65M, R >10 AU • Mixing efficiency D ~ 0.01csH (Johansen & Klahr 2005) • Radial D = 1.5 x vertical D ~ 1015 – 1018 cm2/g __________

17. 10 AU 800 AU Overview of Mixing Results __________ __________

18. Stationary Vertical mix. Radial mix. 2D-Mixing 30x65 grid, 200 species in 1600 reactions 10 AU 800 AU Disk Ionization Degree __________ Comp. Time: 2h 48h 24h >200h Unaffected by diffusion since chemical equilibrium is reached quickly __________

19. Stationary Vertical mix. Radial mix. 2D-Mixing 10 AU 800 AU Gas-phase CO at T<25K __________ Abundant CO gas in cold midplane despite fast freeze-out (steep local abundance gradients) __________

20. Gas-phase CO at T<25K __________ • N(CO) ~ 1017 cm-2 (2D-model) • optical depth is ~ 1 • explains the observations of Dartois et al. (2003) __________

21. Stationary Vertical Radial 2D-Mixing 10x lower diffusion 100x lower diffusion Gas-phase H2CO __________ 10 AU 800 AU Diffusion-dependent H2CO enrichment due to slow surface processes __________

22. Basic Results __________ • “Sandwich”-like disk structure is preserved • Ionization degree is hardly affected • Abundance of photo-controlled species are not affected • Abundances of more complex (organic) species can be enhanced (grain mantle components, e.g. H2CO) __________

23. Disk Chemistry __________ • Large range of temperatures and densities • Importance of radiation fields • Strong coupling between chemistry and dynamics (ionization, temperature structure, …) __________

24. Collaborators __________ • CID collaboration (A. Dutrey, S. Guilloteau, V. Pietu, A. Bacmann, R. Launhardt, Y. Pavlyuchenko, J. Pety, K. Schreyer, V. Wakelam) • D. Wiebe (Moscow): Chemistry with mixing • M. Ilgner (London): Chemistry with mixing • H. Klahr, A. Johansen (MPIA): Disk dynamics • K. Dullemond (MPIA): Grain evolution __________

25. The End __________ __________