CMFGEN - GREAT-ESF Stellar Atmospheres in the Gaia Era ...

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CMFGEN - GREAT-ESF Stellar Atmospheres in the Gaia Era ...

Modeling the wind and photosphere of massive

stars with the radiative transfer code CMFGEN

Image credit: N. Smith (UCB), NASA/ESA

Jose Groh (Max-Planck-Institute for Radioastronomy, Germany)

Acknowledgments: John Hillier (U Pittsburgh, USA)


Outline

1. Introduction to CMFGEN: radiative transfer; pros and cons

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


Outline

1. Introduction to CMFGEN: radiative transfer; pros and cons

2. Spectroscopic analysis of hot stars with CMFGEN: diagnostics

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


Outline

1. Introduction to CMFGEN: radiative transfer; pros and cons

2. Spectroscopic analysis of hot stars with CMFGEN: diagnostics

OB stars

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


Outline

1. Introduction to CMFGEN: radiative transfer; pros and cons

2. Spectroscopic analysis of hot stars with CMFGEN: diagnostics

OB stars

Luminous Blue Variables (LBV)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


Outline

1. Introduction to CMFGEN: radiative transfer; pros and cons

2. Spectroscopic analysis of hot stars with CMFGEN: diagnostics

OB stars

Luminous Blue Variables (LBV)

3. Spectroscopic analysis of hot stars with CMFGEN: example

O stars with weak winds

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. Why do we study massive stars?

Cosmic engines

Massive stars are key constituents of the Universe:

✦ ionizing photons;

✦ energy;

✦ some chemical elements.

M33 galaxy

(size= 10 000 pc)

Image credit: R. Nemiroff & J. Bonnell

First stars and reionization

(size= 50 000 000 pc)

Carina nebula

(size = 15 pc)

Image credit: N. Smith, NASA/ESA credit: Friedich+ 2011

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The need for spectroscopic modeling

Enhance the amount of information obtained from observations

From observations only, one generally measures:

Photometry: magnitudes, colors

NGC 6101

(Marconi+ 2001)

Spectroscopy: EW, line ratios, radial

velocities, spectral energy distribut.

5

H gamma

AG Car

A-hypergiant with a high mass-loss rate

(Groh+ 2011 in prep.)

(Stahl et al. 1982, Stahl et al. 2001, Groh et al. 2009, in prep.)

Normalized Flux

4

3

2

Fe II + Ti II

He I

1

4400 4500 4600 4700 4800

Wavelength (Å)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The need for spectroscopic modeling

Enhance the amount of information obtained from observations

From observations only, one generally measures:

Photometry: magnitudes, colors

NGC 6101

(Marconi+ 2001)

Spectroscopy: EW, line ratios, radial

velocities, spectral energy distribut.

5

H gamma

AG Car

A-hypergiant with a high mass-loss rate

(Groh+ 2011 in prep.)

(Stahl et al. 1982, Stahl et al. 2001, Groh et al. 2009, in prep.)

Normalized Flux

4

3

2

Fe II + Ti II

He I

1

4400 4500 4600 4700 4800

Wavelength (Å)

But we want:

L, Teff, log g, abundances, ionizing fluxes,

Mdot, vinf !

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

General info and purposes

Developed and maintained by John Hillier (University of Pittsburgh, USA);

main reference: Hillier & Miller 1998, ApJ 496, 407.

Code and atomic data are publicly available at:

http://kookaburra.phyast.pitt.edu/hillier/web/CMFGEN.htm

Purpose is to provide:

✦ accurate stellar parameters and abundances → stellar evolu,on

✦ accurate EUV ( λ < 912 Å) radiation fields → nebular photoioniza,on

✦ fundamental data for the study of starbursts → star forma,on

✦ better understanding of the hydrodynamics of winds → radia,on hydrod.

✦ testbed of approximate methods that can be used in more complex

geometries and in inhomogeneous media → mul,-­‐dimensional Rad. Transf.

✦ distances and diagnostics of the progenitor of Type II SNe.

→ extragalac,c studies, cosmology

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Code Suite

CMFGEN → atmospheric and wind structure, T, popula,ons

CMF_FLUX → spectral computa,on

DISPGEN → display package for T, popula,ons, tes,ng, etc

SPEC_PLT → spectral plots, comparison, etc

MAIN_LTE → compute Rosseland opacity for a given composi,on, atomic data

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Atomic data (I)

Opacity project

Seaton 1987, Hummer+ 1993

Bob Kurucz

Bell & Kurucz 1995; http://kurucz.harvard.edu

Keith Butler (Munich)

Sultana Nahar & Anil Prandham

http://www.astronomy.ohio-state.edu/~nahar/nahar_radiativeatomicdata/index.html

NIST

http://nist.gov/pml/data/asd.cfm (energy levels, f values)

http://nist.gov/pml/pubs/atspec/index.cfm (intro to atom.sp.)

Gary Ferland / Verner

charge exchange rates, ground state photoionization cross-sections.

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Atomic data (II)

Atomic data is stored in ASCII files in unique directory:

Example: NIII

/home/jgroh/atomic/NIT/III/24mar07

niiicol.dat → collisional cross sec,on

niiiosc_rev.dat → oscillator strengths/energy levels

niii_auto → autoioniza,on rates

f_to_s_ls → superlevels designa,on

phot_sm_0_A.dat → ground state photoioniza,on cross sec,on

phot_sm_0_B.dat → excited state photoioniza,on cross sec,on

Data format is unique to CMFGEN -- conversion from published data

intro CMFGEN is time consuming (QUESTION A1 from Discussion I yesterday)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Atomic data (II)

Atomic data is stored in ASCII files in unique directory:

Example: NIII

/home/jgroh/atomic/NIT/III/24mar07

niiicol.dat → collisional cross sec,on

niiiosc_rev.dat → oscillator strengths/energy levels

niii_auto → autoioniza,on rates

f_to_s_ls → superlevels designa,on

phot_sm_0_A.dat → ground state photoioniza,on cross sec,on

phot_sm_0_B.dat → excited state photoioniza,on cross sec,on

Data format is unique to CMFGEN -- conversion from published data

intro CMFGEN is time consuming (QUESTION A1 from Discussion I yesterday)

Do not assume the atomic data for a certain

non-standard spectral feature is correct!

see talk

N. Przybilla

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

The problem to be solved

1) Model atmospheric construction: ρ, T, Ni, Ne

✦ generally insensitive to atomic details: gf values, intrinsic line profiles,

coherent/incoherent electron scaPering;

include all species;

include all lines, even those with bad gf values.

2) Precise spectroscopic analysis

✦ use fixed model atmosphere;

✦ details matter: individual lines constrain T eff , log g, and abundances; accurate gf

values (usually) essen,al.

Unfortunately, H, He, CNO, and Fe are strongly coupled to the

atmospheric structure.

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Transfer options

1) Plane parallel (if you still want to use it)

✦ Formal and moment equations

2) Plane parallel co-moving frame

✦ Monotonic vertical velocity field

✦ Radiation computed in frame moving with the gas: opaci,es and emissivity

are isotropic.

✦ Formal and moment equations

✦ Zero order in v/c (only retain v/c term that multiply δ/δv terms)

3) Spherical co-moving frame

✦ radial monotonic velocity field

✦ Radiation computed in frame moving with the gas: opaci,es and emissivity

are isotropic.

✦ Formal and moment equations

✦ Zero order in v/c (only retain v/c term that multiply δ/δv terms)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Transfer options

4) Spherical co-moving frame relativistic

✦ Formal and moment equations

✦ fully relativistic but stationary monotonic flows

5) Spherical time-dependent co-moving frame

✦ First order v/c terms

✦ only implemented for Hubble flows (as in SNe)

✦ Moment equation only

6) Spherical time-dependent co-moving frame fully relativistic

✦ monotonic velocity field

✦ Moment equation only

✦ UNDERGOING TESTS!

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Linearization of rate equations

Consider a function of 1 variable. In general the equation can be written as:

f(x)=0

For some estimate x1, f(x1) ≠ 0. We can compute a correction Δx using a

Taylor expansion. To first order, we require:

0=f(x1)+ Δx f’(x1) (‘ denotes derivative)

This gives

Δx=-f(x1)/f’(x1)

Thus:

x2 = x1 - (-Δx)

This can be easily extended to more than one variable:

note: B = BA, F=STEQ in CMFGEN

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative


1. The radiative transfer code CMFGEN

Constructing

T2*:')43,*7$'5($R%$F+')1I$

the BA matrix

!"#$%&'()*+,-(&.$/($'+0($1*'2$+3324*'$'5($3246&1*7$/1'5$*(17582)1*7$9(6'5:$

!;=?@A%B#$$+66)2+35#C$;5($71-(:$+$8&230D;%?@A%B$:('$2E$:1F4&'+*(24:$

(G4+,2*$H$(+35$8&230$F+')1I$1:$A;CA;C$J2&-(9$8.$F+')1I$-():12*$2E$'5($;K@L%J$

+&72)1'5FC$=*$'51:$+66)2+35$/($5+-($A>CA;$:1F4&'+*(24:$(G4+,2*:$'2$:2&-($DDDM$$

NOPQPPP$3246&(9$:1F4&'+*(24:$(G4+,2*:C$

ARS$$>=?%@A%BS$ $$ $K175()$:'+81&1'.$/5(*$32))(3,2*:$+)($&+)7(C$

$;=%?@A%BS$ $T2*-()7(:$E+:'()C$

;5($:2&4,2*$1:$3+))1(9$24'$4:1*7$B%U%TV$)24,*(:C$R4'$1*$82'5$3+:($/($92$"$')130:S$

!W#$X($$+9Y4:'$'5($(&(F(*':$2E$'5($R%$F+')1I$:2$'5+'$/($:2&-($E2)$'5($E)+3,2*+&$

32))(3,2*:$!1C(CQ$ZA[A#C$%RJ@B\;]B^$]JJ]A;=%B$H$1'$5(&6:$'2$6)(-(*'$:1*74&+)$

F+')13(:C$

!"#$X($+66&.$B%U%TV$)24,*(:$'2$6)(32*91,2*$'5($:1F4&'+*(24:$(G4+,2*:C$

X1'524'$!W#$'51:$92(:$*2'$/2)0C$

J1*3($/($+)($:2&-1*7$E2)$$ZA[AQ$/($92*$*2'$*((9$'5($32))(3,2*$'2$8($2E$5175$6)(31:12*C$

;5($32))(3,2*:$$:1F6&.$*((9$'2$8($)(+:2*+8&($:2$'5+'$/($:,&&$7('$32*-()7(*3($

!6()5+6:$+'$'5($(I6(*:($2E$F2)($1'()+,2*:#C$

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative

B,/3)405'6-67/'

transfer code CMFGEN

Iteration cycle

!"#$%&'()*'+',-./'01'2,/3)405'6-67/*'888'/)6('6-67/'.3092:/*''5/;'/*4'&2>')5:',(/':/5*2,-'?*0


1. The radiative transfer code CMFGEN

Advantages

✦ spherical-symmetry;

✦ non-LTE line formation;

✦ quasi-hydrostatic structure until just below the sonic point;

✦ simultaneous treatment of the atmosphere and wind;

✦ can be applied to hot stars in different evolutionary classes;

✦ wind (micro) clumping;

✦ x-rays in the photosphere and wind;

✦ full line blanketing due to metals with Z up to 30.

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Effects of Line Blanketing on Energy Distribution

Effects of line blanketing on the spectral energy distribution

Key:

H, He;

H, He, CNO

H, He,

CNO, Fe,

etc

(smoothed)

HD93250

L = 1.3 x 10 6 L ! , T eff = 45,700 K, R = 18.3 R ! , log g = 4.0

M = 5.6 x 10 -7 M ! /yr , V ! = 3000 km s -1

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. The radiative transfer code CMFGEN

Cons

✦ momentum equation of the wind is not solved; velocity law has to be

assumed a priori (but can be constrained from observed line profiles).

(Martins+ 2005)

✦ computational time can be large compared to other codes such as

FASTWIND (Puls+ 05; Sergio Simon Diaz & Alex de Koter’s talks);

typical CMFGEN run takes 10-20 hours on 1 CPU; decreases by ~60%

with OPENMP (4 cores).

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. Introduction to CMFGEN: radiative transfer; pros and cons

2. Spectroscopic analysis of hot stars with CMFGEN: diagnostics

OB stars

Luminous Blue Variables (LBV)

3. Spectroscopic analysis of hot stars with CMFGEN: example

O stars with weak winds

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Evolution of an 85 M star (no rotation)


O-type Luminous Blue Variable WR SN

LBV

O-type

WR

(evol. tracks from Meynet & Maeder 2003)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: Teff

(Martins 2011)

He I

He II

Ionization balance:

lines of different ionization

stages from the same

chemical element.

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: Teff

(Martins 2011)

Ionization balance:

lines of different ionization

stages from the same

chemical element.

AG Carinae (LBV)

Same principle for OB, LBVs,

WRs, and other emission line

stars.

(Groh+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: log g

(Martins 2011)

pressure broadening:

strong lines of H not affected by the wind.

NGC 346 MPG 12 (O9.5 V)

(Bouret+ 2003)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: log g

(Martins 2011)

pressure broadening:

strong lines of H not affected by the wind.

AG Carinae (LBV)

log g generally cannot be determined for LBVs and WRs.

(Groh+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: log g

(Martins 2011)

pressure broadening:

strong lines of H not affected by the wind.

W243 (LBV): log g ~0.65

(Ritchie+ 2009)

log g generally cannot be determined for LBVs and WRs (unless has low

Mdot ).

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: luminosity

Fit of the SED; the larger the spectral region the better; may obtain

reddening parameters towards the star, i.e. E(B-V) and Av.

Hen 3-759 (O8 Iaf): log L=5.9 ± 0.2

(Crowther & Evans 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: luminosity

Fit of the SED; the larger the spectral region the better; may obtain

reddening parameters towards the star, i.e. E(B-V) and Av.

AG Car (LBV): absolute error 0.08 dex in log L

log L=6.17 log L=6.17 log L=6.17 log L=6.17

log L=6.17 log L=6.17 log L=6.17 log L=6.17

log L=6.17 log L=6.17 log L=6.17 log L=6.00

log L=6.00 log L=6.00 log L=6.00 log L=6.04

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011

(Groh+ 2009)


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: luminosity

Fit of the SED; the larger the spectral region the better; may obtain

reddening parameters towards the star, i.e. E(B-V) and Av.

R136a1 (WN6h): log L=6.94 ± 0.09

corresponds to M = 265 Msun ! (according to evolutionary models)

log λ [Angs]

(Crowther+ 2010)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: Mdot

(Martins 2011)

Mdot is determined from the strength of UV resonance lines and/or from a

strong recombination line such as Halpha.

]

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: Mdot

(Martins 2011)

Mdot is determined from the strength of UV resonance lines or from a

strong recombination line such as Halpha

Zeta Oph (O9.5 Vnn)

C IV

λ [Angs]

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: Mdot

(Martins 2011)

Mdot is determined from the strength of UV resonance lines or from a

strong recombination line such as Halpha

Eta Carinae (LBV)

C IV

λ [Angs]

(Hillier+ 2001)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: wind (micro)clumping

(Martins 2011)

Constrained from non-saturated UV line profiles (in stars with weak winds)

and/or electron scattering wings of strong recombination lines (e.g. H alpha).

HD 190429A (O4 If+)

λ [Angs]

(Bouret+ 2003)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: wind (micro)clumping

(Martins 2011)

Constrained from non-saturated UV line profiles (in stars with weak winds)

and/or electron scattering wings of strong recombination lines (e.g. H alpha).

AG Carinae (LBV)

λ [Angs]

λ [Angs]

(Groh+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: wind terminal velocity

(Martins 2011)

Vinf is very well constrained from saturated P Cygni line profiles in the UV;

lower limit can be obtained from broadening of strong recombination lines.

HD 93204 (O5 V((f))): vinf = 2900 km/s

λ [Angs] (Martins+ 2005)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: wind terminal velocity

(Martins 2011)

Vinf is very well constrained from saturated P Cygni line profiles in the UV;

lower limit can be obtained from broadening of strong recombination lines.

AG Carinae (LBV): vinf = 105 km/s

λ [Angs]

(Groh+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: chemical abundances

(Martins 2011)

In principle, use lines from a given species that are less affected by model

details; best to use lines from two or more ionization stages.

AV 83 (O7 Iaf+) :N/H=2.2e-6 by number

(Hillier+ 2003)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics: chemical abundances

(Martins 2011)

In principle, use lines from a given species that are less affected by model

details; best to use lines from two or more ionization stages.

AV 83 (O7 Iaf+) :N/H=2.2e-6 by number

(Hillier+ 2003)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


2. Spectroscopic analysis of hot stars with CMFGEN

Main diagnostics

(Martins 2011)

Indicative; has to be adapted to a particular class of objects and dataset

available.

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


1. Introduction to CMFGEN: radiative transfer; pros and cons

2. Spectroscopic analysis of hot stars with CMFGEN: diagnostics

OB stars

Luminous Blue Variables (LBV)

3. Spectroscopic analysis of hot stars with CMFGEN: example

O stars with weak winds

see also poster by L. Mahy

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of hot stars with CMFGEN

Evolution of an 85 M star (no rotation)

O-type Luminous Blue Variable WR SN

Assuming a standard mass-loss

rate prescription (Vink+01)


LBV

O-type

WR

(evol. tracks from Meynet & Maeder 2003)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of hot stars with CMFGEN

Evolution of an 85 M star (no rotation)

O-type Luminous Blue Variable WR SN

Assuming a standard mass-loss

rate prescription (Vink+01)


LBV

Mass-loss rate as a function of

time ultimately determines the

fate of a massive star (Chiosi &

Maeder 1986).

O-type

WR

(evol. tracks from Meynet & Maeder 2003)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of hot stars with CMFGEN

Evolution of an 85 M star (no rotation)

O-type Luminous Blue Variable WR SN

Assuming a standard mass-loss

rate prescription (Vink+01)


LBV

Mass-loss rate as a function of

time ultimately determines the

fate of a massive star (Chiosi &

Maeder 1986).

O-type

WR

(evol. tracks from Meynet & Maeder 2003)

When is the star going to explode, how, and after losing how much mass?

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of O stars with CMFGEN

O dwarfs: atomic model

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of O stars with CMFGEN

O dwarfs: Teff

Show essentially a photospheric optical and UV spectra.

green line = ultraviolet observations of HD 216898

black line = CMFGEN model

Teff diagnostics:

He I λ4471/He II λ4542 and He I λ4713/He II λ4686 →Teff = 34 ± 1 kK

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011

(Marcolino+ 2009)


3. Spectroscopic analysis of O stars with CMFGEN

O dwarfs: Teff

Show essentially a photospheric optical and UV spectra.

green line = ultraviolet observations of HD 216898

black line = CMFGEN model

He I

He II

Teff diagnostics:

He I λ4471/He II λ4542 and He I λ4713/He II λ4686 →Teff = 34 ± 1 kK

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011

(Marcolino+ 2009)


3. Spectroscopic analysis of O stars with CMFGEN

O dwarfs: Teff

Show essentially a photospheric optical and UV spectra.

green line = ultraviolet observations of HD 216898

black line = CMFGEN model

He I

He II

He II

He I

Teff diagnostics:

He I λ4471/He II λ4542 and He I λ4713/He II λ4686 →Teff = 34 ± 1 kK

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011

(Marcolino+ 2009)


3. Spectroscopic analysis of O stars with CMFGEN

O dwarfs: log g

Show essentially a photospheric optical and UV spectra.

green line = ultraviolet observations of HD 216898

black line = CMFGEN model

log g diagnostics:

broadening of wings of Hdelta → log g = 4.0 ± 0.1

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of O stars with CMFGEN

O dwarfs: log g

Show essentially a photospheric optical and UV spectra.

green line = ultraviolet observations of HD 216898

black line = CMFGEN model

Hdelta

Hgamma

log g diagnostics:

broadening of wings of Hdelta → log g = 4.0 ± 0.1

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of O stars with CMFGEN

O dwarfs: Teff and log g

Show essentially a photospheric spectrum. Few spectral lines are affected

by the wind → mass-­‐loss rate diagnos,cs

green line = ultraviolet observations of HD 216898

black line = CMFGEN model

Halpha

Mdot diagnostics:

H alpha, C IV 1548-1551 → log Mdot = -9.35 ± 0.7

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of O stars with CMFGEN

Weak winds of O dwarfs?

Show essentially a photospheric spectrum. Few spectral lines are affected

by the wind: C IV 1548-­‐1551, Halpha → mass-­‐loss rate diagnos,cs

green line = ultraviolet observations of HD 216898

black line = CMFGEN model

Model:

log L = 4.73 ± 0.25

P V

P V

Fe IV forest

C III

Teff = 34 ± 1 kK

log g = 4.0 ± 0.1

log Mdot = -9.35 ± 0.7

v∞ = 1700 ± 500 km/s

Si IV Si IV

Fe IV forest

C IV

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


3. Spectroscopic analysis of O stars with CMFGEN

Weak winds of O dwarfs?

Problem: mass-loss rate found from several studies using CMFGEN is

much lower than what is predicted by theoretical models (Vink et al. 2001).

Key for the plot:

stars: C IV, H alpha w/ CMFGEN (Marcolino+ 09)

open triangles: UV lines, Halpha w. CMFGEN (Martins+ 05)

filled symbols:Halpha w/ FASTWIND (Mokiem+ 07)

Do the standard radiative transfer

models provide reliable massloss

rates?

Role of magnetic fields?

Rotation? X-rays?

Possible role of macroclumps

(optically-thick) in the wind: this

could increase the derived Mdot

(Sundqvist+ 2011).

(Marcolino+ 2009)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


CMFGEN: concluding remarks

State-of-the-art in 1D spectroscopic analysis of massive stars:

spherically-symmetric, non-LTE, simultaneous treatment of

photosphere and wind, full line blanketing (large database of atomic

data, metals up to Z=30), wind clumping, X-rays.

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


CMFGEN: concluding remarks

State-of-the-art in 1D spectroscopic analysis of massive stars:

spherically-symmetric, non-LTE, simultaneous treatment of

photosphere and wind, full line blanketing (large database of atomic

data, metals up to Z=30), wind clumping, X-rays.

Main limitation: momentum equation of the wind is not solved;

velocity law has to be assumed a priori (but can be constrained from

line profiles).

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


CMFGEN: concluding remarks

State-of-the-art in 1D spectroscopic analysis of massive stars:

spherically-symmetric, non-LTE, simultaneous treatment of

photosphere and wind, full line blanketing (large database of atomic

data, metals up to Z=30), wind clumping, X-rays.

Main limitation: momentum equation of the wind is not solved;

velocity law has to be assumed a priori (but can be constrained from

line profiles).

Multi-wavelength analyses of hot massive stars in different evolutionary

stages: OB, LBVs, WRs, SN.

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011


CMFGEN: concluding remarks

Continuous update of CMFGEN: time-dependent winds (Groh & Vink

2011), application to SNe (Dessart & Hillier 2011), multi-dimensional

studies via separate 2D code (Busche & Hillier 2005, Groh+ 2006, 2009)

(Groh & Vink 2011)

Jose Groh - Modeling the wind and photosphere of massive stars with CMFGEN GREAT-ESF workshop, Brussels, 24 June 2011

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