# Dynamical Origin of Wind Structure - PowerPoint PPT Presentation

1 / 35

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. Key Issues. What is effect of wind clumping on line-absorption?

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Dynamical Origin of Wind Structure

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

## 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

### 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?

### Spatial Porosity

• Same amount of material

• More light gets through

• Less interaction between

matter and light

Incident light

porosity length=h

l=0.05r

l=0.1r

l=0.2r

h=0.5r

hºl/f

h=r

h=2r

Step function

## Profile-weighted line column depth

b=1

t¥=1/4

1/2

1

2

}

DV

Velocity

filling factor :

dv

}

Vorosity?

### Absorption reduction

f = 1

RA

0.5

0.2

0.1

tx

smooth, b=1

porous, fv = 1-v/2v¥

t=1/4

t=1/4

1/2

1

2

1

2

### Line absorption

Line-Driven Instabilty sim (SSF)

4

4

Time

(days)

0

1

10

0

1

10

Velocity

Density

CAK

init. cond.

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Weak

Medium

Strong

1

I /Icont

0

-1

0

Wavelength (V¥)

Weak

Medium

Strong

1

I /Icont

0

-1

0

Wavelength (V¥)

Weak

Medium

Strong

## Dynamic absorption spectra

0

-1

0

0

-1

-1

Wavelength (V¥)

0

-1

0

### 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

nonlocal

structured

model

D

log(Density)

c.

a.

b.

nonlocal

local

smooth

CAK

model

model

8

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

8

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

4

Time

(days)

0

CAK init. cond.

1