Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening
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Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening. Pier-Emmanuel Tremblay & Pierre Bergeron Université de Montréal. E. -. +. Hydrogen-line (DA) white dwarfs. Spectroscopic Technique : Bergeron et al. (1992). Photosphere at 20,000 K.

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Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening

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Hydrogen lines in da white dwarfs improved stark broadening

Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening

Pier-Emmanuel Tremblay & Pierre BergeronUniversité de Montréal

E

-

+


Hydrogen line da white dwarfs

Hydrogen-line (DA) white dwarfs


Hydrogen lines in da white dwarfs improved stark broadening

Spectroscopic Technique : Bergeron et al. (1992)


Hydrogen lines in da white dwarfs improved stark broadening

Photosphere at 20,000 K


Hydrogen lines in da white dwarfs improved stark broadening

Mihalas, Hummer & Däppen 1988Occupation probability formalism


Hydrogen lines in da white dwarfs improved stark broadening

Mihalas, Hummer & Däppen1988Occupation probability formalism

T=10,000 K

T=20,000 K

charged - neutral


Hydrogen lines in da white dwarfs improved stark broadening

W

WD0205+250"old models" priorto 1992


Hydrogen lines in da white dwarfs improved stark broadening

Mike Seaton (1990) : MHD88 effects should also be included in line profiles calculations.

Bergeron (1993) : ad-hoc parameter, used in all codes (TLUSTY)

VCS βcritx2


Stark broadening hydrogen

Stark Broadening - Hydrogen


Hydrogen lines in da white dwarfs improved stark broadening

+

+

Constant Electric FieldLinear Stark Effect

-

+

+

+

+


Microfield distribution

Microfield Distribution

β=E/Eo

P(β)dβ

MHD88 : Holtsmark

Nayfonov (1999) : Hooper


Hydrogen lines in da white dwarfs improved stark broadening

r=Rdebye

Vidal, Cooper & Smith (1973)Lemke (1997)

v

Ψ(H)

e-

ρ

Constant Electric FieldLinear Stark Effect

H

Ψ(e)

r=Rmin


Hydrogen lines in da white dwarfs improved stark broadening

Non-adiabatic quantum calculations

n=5

n=4

electronic collisions

no-quenching

n=3

n=2

n=1

t


Hydrogen lines in da white dwarfs improved stark broadening

V(r) + qEz

Hydrogen Atom : V(r)

V(z)

V(z)

z

z

Saddle point

ΔE

Energy of Nth level


Hydrogen lines in da white dwarfs improved stark broadening

Mihalas, Hummer & Däppen 1988Occupation probability formalism

Bound state

Free State

ΔE


Cr it value not arbitrary

βcrit value not arbitrary!

Βcrit

}electronic collisions


Seaton 1990

Seaton (1990)

High Fields

Low Fields

Seaton (1990) : first non-ideal profiles using approximate electronic broadening profiles

Bergeron (1993) : ad-hoc parameter.


This work

This work

  • Vidal, Cooper & Smith (1973) electron broadening theory.

  • Non-ideal correction for proton perturbations (MHD 88, Seaton 90).


This work1

This work

  • Non-ideal correction for electron perturbations (MHD 88).

  • It accounts for about 10% of the non-ideal effects.

  • Consistent implementation of the MHD88 Theory.


Hydrogen lines in da white dwarfs improved stark broadening

VCSThis WorkM. Seaton

(Lemke 1997)

T=10,000 K

Log Ne =17


Hydrogen lines in da white dwarfs improved stark broadening

Wiese et al. (1972)


Hydrogen lines in da white dwarfs improved stark broadening

0.7 M

0.55 M

0.7 M

0.55 M


Hydrogen lines in da white dwarfs improved stark broadening

0.7 M

0.55 M

0.7 M

0.55 M


Hydrogen lines in da white dwarfs improved stark broadening

ΔTeff =+100 KΔlog g = +0.06


Hydrogen lines in da white dwarfs improved stark broadening

HZ43

GD71

This work

VCS βcritx2


Hydrogen lines in da white dwarfs improved stark broadening

Independent constraints


40 eri b

40 Eri B


Conclusion

Conclusion

  • Spectroscopic technique (Bergeron et al. 1992).

  • Current model atmospheres use MHD88 EOS and VCS Stark broadening profiles (Lemke 1997 tables)

  • Here we add MHD88 inside the VCS broadening theory in a consistent way for the first time.

  • We are currently looking at further implications at low and high Teff, UV lines and DO white dwarfs.


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