1. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 1 L 6: Circumstellar Disks Background image: HH 30 JHK HST-NICMOS, courtesy Padgett et al. 1999, AJ 117, 1490

2. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 2 L 6: Circumstellar Disks Recent reviews include: Protostars & Planets IV, Mannings, Boss & Russell (eds.) 12 Articles on Disks 5 Articles on Outflows Zuckerman, ARAA 2001, 39: 549 Zuckerman & Song (?), ARAA 2004, in press

3. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 3 L 6: Circumstellar Disks and Outflows

4. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 4 Flattened structures - Disks Inevitable consequence of star formation Rotation Magnetic Fields

5. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 5 Flattened structures - Disks Inevitable consequence of star formation Rotation P.S. Laplace 1796, 1799 Exposition du systeme du monde Mechanique celeste I. Kant 1755 Allgemeine Naturgeschichte und Theorie des Himmels Planetary System Formation...another lecture – another time...

6. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 6 Mass Loss - Outflows Inevitable consequence of star formation Angular Momentum Loss - Redistribution The race between mass accretion & mass loss processses see review article

7. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 7 Lynden-Bell & Pringle 1974, MNRAS 168, 603: Keplerian Disk Differential Rotation + Viscosity Mass Transport Inwards Angular Momentum Transport Outwards See also Gösta Gahm’s lecture

8. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 8 `standard model´: e.g., Frank, King & Raine Accretion Power in Astrophysics self-consistent structure of steady, optically thick  -disk blackbody radiation and thin disk approximation When / Where valid ?

9. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 9 Example: Lin & Papaloizou opacities (1985 PP II) Icy grains H - Molecules bound-free free-free (Cox-Stuart-Alexander)

10. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 10 Beckwith et al. 2000, PP IV Grain Opacities

11. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 11 `standard model´: e.g., Frank, King & Raine Accretion Power in Astrophysics self-consistent structure of steady, optically thick a-disk

12. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 12 40 observed SEDs of T Tauri Stars & `mean model´ of star+disk D´Alessio et al. 1999 HABE Disk Structure: Dullemond & Dominik 2004 includes vertical Temperature distribution

13. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 13 Gas Disks – Structure Models Steady Disks around Single Stars Boundary Conditions R in : boundary layer, magnetosphere? R out : ?, interstellar turbulence? Viscosity MHD/rotation (Hawley & Balbus 1995) Opacity , T, …, XYZ,...,  , ...,  ...) ModelsAdams & Shu 1986 (flat) [examples] Kenyon & Hartmann 1987 (flared) Malbet & Bertout 1991 (vertical structure) D´Allessio et al. 1998,... 2003 Aikawa & Herbst 1998 (chemistry) Nomura 2002 (2D) Wolf 2003 (3D)

14. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 14 Observations of Keplerian Disks JE Keeler 1895 ApJ 1: 416 The Rings of Saturn spectrum image Courtesy Brandeker, Liseau & Ilyn 2002

15. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 15 2 Categories of Disks T Tauri Disks: around young stars (0.1 - 10 Myr) of half a solar mass (0.1 - 1 Msun) at 150 pc distance (50 - 450 pc) in and/or near molecular clouds Accretion Disks Debris Disks: around young ms-stars (10 - 400 Myr) of about a solar mass (1 - 2 Msun) at 20 pc distance (3 - 70 pc) in the general field Vega-excess stellar disks gas rich gas poor

16. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 16 Frequency of Disks High Rate of occurence around young stars NGC 2024 86% Trapezium cluster 80% IC 348 65% Haisch et al. 2001 and around BDs in Trapezium cluster 65% Muench et al. 2001 see also G. Gahm’s lecture

17. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 17 Gas Disks - Sizes Size scale (AU)Tracer (mode)*Reference 20000CS (1- 0) (S)Kaifu et al. 1984 5000 - 10000 13 CO (1- 0) (S)Fridlund et al. 1989 1400C 18 O (1- 0) (I)Sargent et al. 1988 <5001.4 mm (I)Woody et al. 1989 45 + 1600mm, cm (I)Keene & Masson 1990 2000.8 mm (I)Lay et al. 1994 7000H 13 CO + (1- 0) (S)Mizuno et al. 1994 50000.7 - 1 mm (S)Ladd et al. 1995 4000 - 6000C 18, 17 O (2- 1) (S)Fuller et al. 1995 1200 13 CO (1- 0) (I)Ohashi et al. 1996 4000H 13 CO + (1- 0) (I)Saito et al. 1996 5000H 12, 13 CO + (1- 0) (S, I)Hogerheijde et al.1997, 98 2500C 18 O + (1- 0) (I)Momose et al. 1998 Fridlund et al. 2002 for One Object Size depends on frequency/mode of observation * S=single dish, I=Interferometer

18. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 18 Gas Disks - Sizes T Tauri/HABE disks 50 - 100 AUDust: mm-continuum interferometry 100 - 300 AUDust: scattered stellar light 300 AUGas: CO lines (evidence for Kepler rotation) Silhouettte disks (``proplyds´´) up to 1000 AUDust: scattered stellar light generally

19. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 19 Gas Disks - Masses H 2 Gas Directly CO and Dust

20. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 20 Gas Disks - Masses Lower limit: 0.001 to 1 M Sun (based on mm / submm continuum) How good are these numbers ? Do we understand disks ? ? Why ? dust gas +dust Solar Minimum Mass Nebula = 0.002 M Sun

21. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 21 Gas Disks - Make up gas disks consist of gas and dust what components? what proportions?

22. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 22 2 T Tauri Disks - Make up van Zadelhoff 2002 13 CO (1)* HCO + (5) HCN (5) CO (200) HCO + (200) HCN (200 ) LkCa 15TW Hya * (N) = depletion factor

23. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 23 2 T Tauri Disks - Chemistry Molecular abundances (rel. H 2 ) Species LkCa 15TW Hya CO3.4 ( - 7)5.7 ( - 8) HCO + 5.6 (-12)2.2 (-11) H 13 CO + < 2.6(-12)3.6 (-13) DCO + ….7.8 (-13) CN2.4 (-10)1.2 (-10) HCN3.1 (-11)1.6 (-11) H 13 CN….< 8.4(-13) HNC….< 2.6(-12) DCN….< 7.1(-14) CS8.5 (-11)…. H 2 CO4.1 (-11)< 7.1(-13) CH 3 OH< 3.7(-10)< 1.9(-11) N 2 H + < 2.3(-11)< 1.8(-11) H 2 D + < 1.5(-11)< 7.8(-12) Thi 2002

24. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 24 Gas Disks - Evolution Time scales (viscous accretion disk) t dyn ~  t therm ~  (H/R) 2 t visc t dyn ~ 1/  Kepler  ~ 10 -3 - 10 -2 H/R << 1 if T ~ R -1/2, t visc ~ R t visc ~ 10 5 yr (  /0.01) -1 (R/10 AU)

25. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 25 Gas Disks - Evolution Disk dispersal and disk lifetimes Physical Mechanisms Hollenbach et al. 2000 PPIV SE = Stellar Encounter (tidal stripping) WS = Stellar wind stripping evap E = photoevaporation external star evap c = photoevaporation central star All for Trapezium conditions

26. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 26 Gas (T Tauri) Disks - Evolution Disk dispersal and disk lifetimes Mass accretion evolution Calvet et al. 2000 PPIV Average Error Bar

27. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 27 Gas Disks to Debris Disks – Evolution ? See also lecture by G. Gahm f dust =  L IR /L vs stellar age (F)IR - excess Stellar luminosity (bolometric) How ?

28. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 28 Gas Disks to Debris Disks – Evolution ? Spangler et al. 2001 Clusters Individual stars (= 1 zodi)

29. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 29 Debris Disks - Properties debris (collision products) or particulate (gas free) percentage of Main Sequence stars (15%?) (observationally) biased towards Spectral Type A for (detectable) ages <400 Myr Habing et al. 1999, 2001 disk sizes 100 to 2000 AU disk masses >1 to 100 M Moon (small grains) Pre-IRAS Solar system Zodi US Navy Chaplain G. Jones 1855 AJ 4, 94 Vega Blackwell et al. 1983

30. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 30 http://www.hep.upenn.edu/~davidk/bpic.html

31. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 31 How much Gas in Dusty Debris Disks ? Disk evolution hypothesis: gas rich to gas poor Census of material (m gas /m dust ): planet formation planet formation: enough gas for GPs ? planet formation: time scales ? planet formation: seeds of Life ? See review

32. rene@astro.su.se L6 - Stellar Evolution II: August-September, 2004 32 L 6: conclusions circumstellar disks are a consequence of star formation disks and bipolar outflows/jets are connected disks form potentially planetray systems L 6: open questions what are the physics of disks and their outflows ? how do disks evolve ? what fraction forms planetary systems ? when and how ?