Modelling of spectra and model atmospheres of evolved stars

(A talk from the parallel world)(A talk from the parallel world)

Yakiv V.PavlenkoYakiv V.Pavlenko

Main astronomical observatoryMain astronomical observatory

27 Sabolotnoho, Kyiv, Ukraine 27 Sabolotnoho, Kyiv, Ukraine

www.mao.kiev.ua/staff/ypwww.mao.kiev.ua/staff/yp

04/02/06 4VIII Torino Workshop, Granada,

Febr.2006

CollaboratorsCollaborators

Carlos Abia (UG)Carlos Abia (UG)Greg Harries Greg Harries

(UCL)(UCL)Yakovina Yakovina

Larisa(MAO)Larisa(MAO)Kaminsky Bogdan Kaminsky Bogdan

(MAO)(MAO)Hugh Jones (UH)Hugh Jones (UH)

Nye Nye Evans(Keele)Evans(Keele)

Hilmar Hilmar Duerbeck(OU)Duerbeck(OU)

Sveta Zhukovska Sveta Zhukovska (MAO)(MAO)

Thomas GeballeThomas Geballe

(UKIRT)(UKIRT)

04/02/06 5VIII Torino Workshop, Granada,

Febr.2006

Stars of interest:Stars of interest:Hydrogen-rich starsHydrogen-rich stars--- --- M-giantsM-giants--- C-giants--- C-giants--- V838 Mon--- V838 MonHydrogen poor starsHydrogen poor stars--- --- R CrBR CrB--- Sakurai’s object--- Sakurai’s object

04/02/06 6VIII Torino Workshop, Granada,

Febr.2006

OutlineOutlineModel atmospheres and fits Model atmospheres and fits

to SEDsto SEDsIsotopic ratios (Isotopic ratios (1212C/C/1313C)C)Abundances (Lithium Abundances (Lithium

abundances)abundances)

04/02/06 7VIII Torino Workshop, Granada,

Febr.2006

PROCEDUREPROCEDURE

Model atmospheresModel atmospheres

SAM12 (ATLAS12)SAM12 (ATLAS12)

1D,1D,

Convection + Convection + radiation,radiation,

LTE,LTE,

No sinks and sources No sinks and sources of energyof energy

Opacity sampling forOpacity sampling for

line opacityline opacity

Synthetic spectraSynthetic spectra WITAWITA1D,1D,LTE,LTE,Voigt function for Voigt function for

lineslinesVCS theory for H VCS theory for H

lineslinesSEDsSEDs

04/02/06 8VIII Torino Workshop, Granada,

Febr.2006

OPACITIES:OPACITIES:

C/O < 1,C/O < 1,Opacity Opacity

sources:sources:

VO, TiO;VO, TiO;

HH22O, COO, CO

MethaneMethane

C/O > 1C/O > 1

CN, CO, CN, CO, CH, CH, CC22,HCN, C,HCN, C33,,

--- [H]?? --- [H]??

--- isotopes!--- isotopes!

04/02/06 9VIII Torino Workshop, Granada,

Febr.2006

Opacities (missed continuum Opacities (missed continuum absorption in the blue, line lists absorption in the blue, line lists (both atomic and molecular), (both atomic and molecular), isotops,isotops,

chemical abundances and chemical abundances and equilibrium,equilibrium,

3-D convection,3-D convection, sphericity effects,sphericity effects, the dust,the dust, stellar winds.stellar winds.

Problems:

04/02/06 10VIII Torino Workshop, Granada,

Febr.2006

Astronomy often progresses amoeba-like: the advance in one pseudopod may not move the animal very far, but permits other parts to advance in their turn and can reveal portions of the organism that are in danger of being left behind. V.Trimble, R.A.Bell, Q.Jl.R.astr.Soc.(1981),22, 361-

379

04/02/06 11VIII Torino Workshop, Granada,

Febr.2006

C-giantsC-giants

04/02/06 12VIII Torino Workshop, Granada,

Febr.2006

New grid 1-D model New grid 1-D model atmosphesatmosphes

Teff= 3400 – 2000Teff= 3400 – 2000 log g = 1. 0log g = 1. 0 metallicity -4, -3.5, -3, -2.5, -2, -1.5, -metallicity -4, -3.5, -3, -2.5, -2, -1.5, -

1, -0.5, 0, 1, 1.5, 21, -0.5, 0, 1, 1.5, 2 [C/O] = 0.003, 0.007, 0.01, 0.02, 0.03 [C/O] = 0.003, 0.007, 0.01, 0.02, 0.03 New HCN & NHCNew HCN & NHC

04/02/06 13VIII Torino Workshop, Granada,

Febr.2006

04/02/06 14VIII Torino Workshop, Granada,

Febr.2006

04/02/06 15VIII Torino Workshop, Granada,

Febr.2006

Sakurai's object (V4334 Sakurai's object (V4334 Sgr)Sgr)

04/02/06 16VIII Torino Workshop, Granada,

Febr.2006

04/02/06 17VIII Torino Workshop, Granada,

Febr.2006

04/02/06 18VIII Torino Workshop, Granada,

Febr.2006

04/02/06 19VIII Torino Workshop, Granada,

Febr.2006

04/02/06 20VIII Torino Workshop, Granada,

Febr.2006

04/02/06 21VIII Torino Workshop, Granada,

Febr.2006

V838 MonV838 Mon

04/02/06 22VIII Torino Workshop, Granada,

Febr.2006

04/02/06 23VIII Torino Workshop, Granada,

Febr.2006

04/02/06 24VIII Torino Workshop, Granada,

Febr.2006

“...Given the web of interconnected uncertainties and errors presented here, one is initially tempted to give up on stellar atmospheres completely and turn to something simple like cosmology.”

V.Trimble & R.A, Bell:

04/02/06 25VIII Torino Workshop, Granada,

Febr.2006

The quality of fits to The quality of fits to observed spectra depends observed spectra depends

on:on:OBSERVED SPECTRA OBSERVED SPECTRA

(slopes, de-redenning, (slopes, de-redenning, resolution)resolution)

Model atmospheresModel atmospheresInput data for the synthetic Input data for the synthetic

spectraspectra

04/02/06 26VIII Torino Workshop, Granada,

Febr.2006

Fine analysis of stellar spectra(Abundance analysis)

Input:Input:

a) Model atmospheresa) Model atmospheres

b) Line listsb) Line lists

c) Partition functons, dissociation c) Partition functons, dissociation constants...constants...

d) chemical boundsd) chemical bounds

04/02/06 27VIII Torino Workshop, Granada,

Febr.2006

Lithium in C-starsLithium in C-stars

04/02/06 28VIII Torino Workshop, Granada,

Febr.2006

04/02/06 29VIII Torino Workshop, Granada,

Febr.2006

04/02/06 30VIII Torino Workshop, Granada,

Febr.2006

Problems of Li abundance Problems of Li abundance determination in C-giantsdetermination in C-giants

Line lists (CN, C2, ...)Line lists (CN, C2, ...) Heavy elements (lists, abundances)Heavy elements (lists, abundances) 3D3D NLTENLTE VeilingVeiling

04/02/06 31VIII Torino Workshop, Granada,

Febr.2006

CO bandsCO bands((12C/13C isotopic ratio12C/13C isotopic ratio))

04/02/06 32VIII Torino Workshop, Granada,

Febr.2006

12C/13C in globular 12C/13C in globular clustersclusters

M71: [Fe/H] = -0.7M71: [Fe/H] = -0.7 M5: [Fe/H] = -1.2M5: [Fe/H] = -1.2 M13: [Fe/H]= -1.4M13: [Fe/H]= -1.4 M3: [Fe/H] = -1.6M3: [Fe/H] = -1.6

04/02/06 33VIII Torino Workshop, Granada,

Febr.2006

Fits to observed spectraFits to observed spectra

04/02/06 34VIII Torino Workshop, Granada,

Febr.2006

04/02/06 35VIII Torino Workshop, Granada,

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04/02/06 36VIII Torino Workshop, Granada,

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04/02/06 37VIII Torino Workshop, Granada,

Febr.2006

Pavlenko, Yakiv V., Jones, Hugh R. A., Longmore, Andrew J., 2003, 'Carbon abundances and 12C/13C from globular cluster giants.' MNRAS, 345, 311-324.

04/02/06 38VIII Torino Workshop, Granada,

Febr.2006

12C/13C in Sakurai’s 12C/13C in Sakurai’s objectobject

Main problems to be solved: Main problems to be solved: --- dust veiling--- dust veiling --- Model atmosphere with peculiar --- Model atmosphere with peculiar

abundancesabundances

04/02/06 39VIII Torino Workshop, Granada,

Febr.2006

04/02/06 40VIII Torino Workshop, Granada,

Febr.2006

04/02/06 41VIII Torino Workshop, Granada,

Febr.2006

04/02/06 42VIII Torino Workshop, Granada,

Febr.2006

ConclusionsConclusions

Model atmospheres and theoretical Model atmospheres and theoretical spectra must be obtained in the spectra must be obtained in the framework of self-consistent approach.framework of self-consistent approach.

Iterative procefure of abundances Iterative procefure of abundances determination should be implemented.determination should be implemented.

Different spectral ranges should be used.Different spectral ranges should be used. Input data used in modelling must be Input data used in modelling must be

improved.improved.

04/02/06 43VIII Torino Workshop, Granada,

Febr.2006

... But this is a snare and a delusion, as the more esoteric branches of astrophysics have been built up on the assumption that we understandthings like stellar masses, evolution(YP: and abundances:). ... Thus if the fundation is shaky,so is superstructure.

V.Trimble,R.A.Bell:

to be continued...

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