Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening
Download
1 / 30

Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening - PowerPoint PPT Presentation


  • 88 Views
  • Uploaded on

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.

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

PowerPoint Slideshow about ' Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening' - len


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.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 - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Hydrogen Lines in DA White Dwarfs: Improved Stark Broadening

Pier-Emmanuel Tremblay & Pierre BergeronUniversité de Montréal

E

-

+





Mihalas, Hummer & Däppen 1988Occupation probability formalism


Mihalas, Hummer & Däppen1988Occupation probability formalism

T=10,000 K

T=20,000 K

charged - neutral


W

WD0205+250"old models" priorto 1992


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 in line profiles calculations.


+ in line profiles calculations.

+

Constant Electric FieldLinear Stark Effect

-

+

+

+

+


Microfield distribution
Microfield Distribution in line profiles calculations.

β=E/Eo

P(β)dβ

MHD88 : Holtsmark

Nayfonov (1999) : Hooper


r=R in line profiles calculations.debye

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

v

Ψ(H)

e-

ρ

Constant Electric FieldLinear Stark Effect

H

Ψ(e)

r=Rmin


Non-adiabatic quantum calculations in line profiles calculations.

n=5

n=4

electronic collisions

no-quenching

n=3

n=2

n=1

t


V(r) + qEz in line profiles calculations.

Hydrogen Atom : V(r)

V(z)

V(z)

z

z

Saddle point

ΔE

Energy of Nth level


Mihalas, Hummer & Däppen 1988 in line profiles calculations.Occupation probability formalism

Bound state

Free State

ΔE


Cr it value not arbitrary
β in line profiles calculations.crit value not arbitrary!

Βcrit

}electronic collisions


Seaton 1990
Seaton (1990) in line profiles calculations.

High Fields

Low Fields

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

Bergeron (1993) : ad-hoc parameter.


This work
This work in line profiles calculations.

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

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


This work1
This work in line profiles calculations.

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

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

  • Consistent implementation of the MHD88 Theory.


VCS in line profiles calculations.This WorkM. Seaton

(Lemke 1997)

T=10,000 K

Log Ne =17


Wiese et al. (1972) in line profiles calculations.


0.7 M in line profiles calculations.

0.55 M

0.7 M

0.55 M


0.7 M in line profiles calculations.

0.55 M

0.7 M

0.55 M


Δ in line profiles calculations.Teff =+100 KΔlog g = +0.06


HZ43 in line profiles calculations.

GD71

This work

VCS βcritx2


Independent constraints in line profiles calculations.


40 eri b
40 Eri B in line profiles calculations.


Conclusion
Conclusion in line profiles calculations.

  • 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.


ad