1 / 35

Dynamical Origin of Wind Structure

This study explores how "velocity porosity" affects the absorption properties of P-Cygni lines in astronomical contexts. Key issues addressed include the impact of wind clumping on line absorption, comparisons between velocity dispersion and spatial porosity, and the identification of relevant scaling parameters. The research uses dynamical models to emphasize the importance of these factors for phenomena such as the predicted mass loss rates in stellar winds. The results indicate that velocity clumping is essential for accurate modeling of line-driven instabilities and absorption spectra.

avital
Télécharger la présentation

Dynamical Origin of Wind Structure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dynamical Origin of Wind Structure Stan Owocki Bartol Research Institute Department of Physics & Astronomy University of Delaware The effect of “velocity porosity” on P-Cygni line absorption strength

  2. Key Issues • What is effect of wind clumping on line-absorption? • Velocity dispersion vs. Spatial Porosity • What are relevant scaling parameters (cf. fr, h=l/f)? • In dynamical model, how important for, eg. PV?

  3. Spatial Porosity • Same amount of material • More light gets through • Less interaction between matter and light Incident light

  4. porosity length=h Effective opacity

  5. l=0.05r l=0.1r l=0.2r Porous envelopes h=0.5r hºl/f h=r h=2r

  6. Step function Profile-weighted line column depth

  7. b=1 t¥=1/4 1/2 1 2 Line absorption trough

  8. Velocity vs. Mass

  9. Velocity vs. Mass } DV Velocity filling factor : dv }

  10. Velocity vs. Mass

  11. Vorosity? “Velocity Porosity”

  12. Absorption reduction f = 1 RA 0.5 0.2 0.1 tx

  13. smooth, b=1 porous, fv = 1-v/2v¥ t=1/4 t=1/4 1/2 1 2 1 2 Line absorption

  14. Line-Driven Instabilty sim (SSF)

  15. 4 4 Time (days) 0 1 10 radius (R*) 0 1 10 radius (R*) Velocity Instability model Density CAK init. cond.

  16. Profile-weighted line column depth 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  17. Profile-weighted line column depth 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  18. Dynamic absorption spectrum-weak line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  19. Dynamic absorption spectrum-weak line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  20. Dynamic absorption spectrum - med. line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  21. Dynamic absorption spectrum - med. line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  22. Dynamic absorption spectrum-strong line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  23. Dynamic absorption spectrum-strong line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  24. Weak Medium Strong Time-Averaged Absorption Profiles 1 I /Icont 0 -1 0 Wavelength (V¥)

  25. Weak Medium Strong Time-Averaged Absorption Profiles 1 I /Icont 0 -1 0 Wavelength (V¥)

  26. Weak Medium Strong Dynamic absorption spectra 0 -1 0 0 -1 -1 Wavelength (V¥) 0 -1 0

  27. Summary • Spatial porosity for continuum opacity • characterized by “porosity length” h=l/fr • But for line opacity, key is“velocity clumping” • characterized by fvel(and tSob of smoothed wind) • Line-driven instability suggests: • fvel ~= 0.7-0.8 (maybe 0.5 if seeded by low freq. pert) • Mdot misunderestimated by fvel , i.e. 0.5-0.8 • Maybe upto a factor 2 of the ca. 10 needed for PV

  28. nonlocal structured model 2D Simulation of Co-rotating Interaction Regions D log(Density) c. a. b. nonlocal local smooth CAK model model

  29. Profile-weighted line column depth 8 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  30. Dynamic absorption spectrum-med. line 8 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  31. Dyn. abs. spectrum - very strong line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  32. Dyn. abs. spectrum - very strong line 4 Time (days) 0 CAK init. cond. -1 0 Wavelength (V¥)

  33. Instability model: Mdot 4 Time (days) 0 CAK init. cond. 1 radius (R*) 10

More Related