Line formation in CO5BOLD simulation of red supergiant
description
Transcript of Line formation in CO5BOLD simulation of red supergiant
Line formation in CO5BOLD simulation of red supergiant
A. Chiavassa, B. Plez, E. Josselin,*
B. Freytag**
*GRAAL, Montpellier, France
**LANL, USA; Uppsala University, Sweden
CO5BOLD Workshop, June 2006
RSG have complex spectra …
- strong molecular bands (TiO ...)
- large “macroturbulence” (~15 km s-1)
continuum poorly defined, spectrum synthesis is difficult ...
1D does not work for RSGs !
Post-Processing
τλ ijk = χ ijk Tijk , ρijk ,λ ⋅ 1− v ijk / c( )( )1
k
∑ ρijkδzijk
Iλij = Bλ Tijk( )k∑ ⋅exp −τ λijk( )δτ λijk
avec
6.3 sec / λ
(3153 rayons)
R = λ/λ = c/v 85000
~ 30 h / 1000 A
interpolation of ijk
exponential
Strongline
Pseudo-ContinuumLine
Very Strong Line (Fe I)
Very Strong Line
Weak Line (Si I) Strong Line (Ca I)
Pseduo - Continuum
Pseudo-ContinuumLine
Strongline
Weak Line
1
43
2
Pseudo Continuum line
1
3 4
2
Strong line
Problems
No microturbolence
Additional microturbolence
1.5 km/s
Additional microturbolence
5 km/s
Conclusions
• Intensity comes from different regions at different depth
• Velocity does not behave the same at different depth
• 3D models do not reproduce high and low excitation line
Needs
• Increase model resolution to 5003 points
• Increase model temperature at least to 3600K
• non-grey radiation transport