1. Radiatively Driven Winds and Aspherical Mass Loss Stan Owocki U. of Delaware collaborators: Ken GayleyU. Iowa Nir Shaviv Hebrew U. Rich TownsendU. Delaware Asif ud-DoulaNCSU

2. General Themes Lines vs. Continuum driving Oblate vs. Prolate mass loss Smooth vs. Porous medium Rotation vs. Magnetic field

3. Radiative force  ~ e.g., compare electron scattering force vs. gravity  g el g grav   e L 4  GMGMc r  L 4  r 2 c Th  e GM 2  For sun,  O ~ 2 x 10 -5 But for hot-stars with L~ 10 6 L O ; M=10-50 M O... if  gray

4. Q~  ~ 10 15 Hz * 10 -8 s ~ 10 7 Q ~ Z Q ~ 10 -4 10 7 ~ 10 3 Line Scattering: Bound Electron Resonance  lines ~Q  Th g lines ~10 3  g el L  L thin } if  lines ~10 3  el  1 for high Quality Line Resonance, cross section >> electron scattering

5. Optically Thick Line-Absorption in an Accelerating Stellar Wind For strong, optically thick lines:

6. CAK model of steady-state wind inertiagravityCAK line-force Solve for: Mass loss rate Wind-Momentum Luminosity Law Velocity law Equation of motion:  < 1 CAK ensemble of thick & thin lines

7. Wind Compressed Disk Model Bjorkman & Cassinelli 1993

8. Wind Compressed Disk Model Bjorkman & Cassinelli 1993

9. Wind Compressed Disk Simulations Vrot (km/s) = 200 250 300 350 400 450 radial forces only WCD Inhibition by non-radial line-forces

10. Wind Compressed Disk Simulations Vrot (km/s) = 200 250 300 350 400 450 radial forces only Vrot = 350 km/s with nonradial forces

11. Vector Line-Force from Rotating Star dv n /dn faster polar wind slower equatorial wind r Max[dv n /dn] (2) Pole-equator aymmetry in velocity gradient Net poleward line force from: r Flux (1) Stellar oblateness => poleward tilt in radiative flux N

12. Gravity Darkening increasing stellar rotation

13. Vector line-force; With gravity dark.

14. Effect of gravity darkening on line-driven mass flux w/ gravity darkening, if F(  )~g eff (  ) highest at pole highest at pole

15. Rotational effect on flow speed *

16. Smith et al. 2002

17. Smith et al. 2003

18. But lines can’t explain eta Car mass loss O O

19. Super-Eddington Continuum-Driven Winds moderated by “porosity”

20. Continuum Eddington parameter compare continuum force vs. gravity  g c g grav   c L 4  GMGMc r  L 4  r 2 c c  GM 2  constant in radius => no surface modulation if  gray

21. Convective Instability Classically expected in energy-generating core –e.g., CNO burning =>  ~ T 10-20 => dT/dr > dT/dr ad But envelope also convective where  (r) -> 1 –e.g.,  Pup:  * ~1/2 => M(r) < M * /2 convective! For high density interior => convection efficient –L conv > L rad  L crit =>  rad (r) < 1: hydrostatic equilibrium Near surface, convection inefficient => super-Eddington –but flow has M ~ L/a 2 –implies wind energy Mv esc 2 >> L –would“tire” radiation, stagnate outflow –suggests highly structured, chaotic surface. Joss, Salpeter Ostriker 1973.

22. Photon tiring

23. Stagnation of photon-tired outflow

24. Shaviv 2001

25. Power-law porosity

26. Effective Opacity for "Blob"

27. Porous opacity “porosity length”

28. Super-Eddington Wind Wind driven by continuum opacity in a porous medium when  * >1 Shaviv 98-02 At sonic point: “porosity-length ansatz” O

29. Power-law porosity Now at sonic point:

30. Results for Power-law porosity model

31. Effect of gravity darkening on porosity-moderated mass flux w/ gravity darkening, if F(  )~g eff (  ) highest at pole highest at pole

32. Eta Carina

33. Summary Themes Lines vs. Continuum driving Oblate vs. Prolate mass loss Smooth vs. Porous medium Rotation vs. Magnetic field

34. Wind Magnetic Confinement Ratio of magnetic to kinetic energy density: e.g, for dipole field, q=3;  ~ 1/r 4 for present day eta Car wind, need      G for Homunclus, need      G 

35. MHD Simulation of Wind Channeling Confinement parameter A. ud Doula PhD thesis 2002 No Rotation

36. Field aligned rotation A. ud-Doula, Phd. Thesis 2002

37. Disk from Prograde NRP w=0.95 ;  V amp = a = 25 km/s =  V orb

38. Azimuthal Averages vs. r, t Azimuthal Velocity 510 Mass 1.0 1.2 r/R * Kepler Number 0.981.0 510 1.0 1.2 r/R * time (days) Density 0 NRP Off NRP On