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Dynamical Origin of Wind Structure

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Dynamical Origin of Wind Structure

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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

- 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?

• 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?

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-Driven Instabilty sim (SSF)

4

4

Time

(days)

0

1

10

radius (R*)

0

1

10

radius (R*)

Velocity

Instability model

Density

CAK

init. cond.

Profile-weighted line column depth

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Profile-weighted line column depth

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dynamic absorption spectrum-weak line

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dynamic absorption spectrum-weak line

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dynamic absorption spectrum - med. line

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dynamic absorption spectrum - med. line

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dynamic absorption spectrum-strong line

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dynamic absorption spectrum-strong line

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

- 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

Profile-weighted line column depth

8

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dynamic absorption spectrum-med. line

8

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dyn. abs. spectrum - very strong line

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Dyn. abs. spectrum - very strong line

4

Time

(days)

0

CAK init. cond.

-1

0

Wavelength (V¥)

Instability model: Mdot

4

Time

(days)

0

CAK init. cond.

1

radius (R*)

10