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Spectral diagnostics of massive stars

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Title: Spectral diagnostics of massive stars


1
Spectral diagnostics of massive stars
  • diagnostic problem
  • high luminosity ? enormous energy and
    momentum
  • density of
    radiation field

NLTE
stellar winds
  • Model atmospheres and radiative transfer
  • detailed NLTE treatment
  • radiation-hydrodynamics of line-driven winds
  • spherical extension

2
UV spectrum of O4 supergiant z Puppis
Pauldrach, Puls, Kudritzki et al. 1994, SSRev,
66, 105
3
P Cygni profiles and vinfinity
fit of v8 5 accuracy
Kudritzki Puls, 2000, AARA 38, 613
4
Ha emission O-star
  • Model calculation

Variation of by 20
Kudritzki Puls, 2000, AARA 38, 613
5
FUV- and IR- excess through winds
winds
effects on ionization!
Gabler, Gabler, Kudritzki, Puls, Pauldrach, 1989,
AA 226, 162
6
Spectral diagnostics of massive stars
  • diagnostic problem
  • high luminosity ? enormous energy and
    momentum
  • density of
    radiation field

NLTE
stellar winds
  • Model atmospheres and radiative transfer
  • detailed NLTE treatment
  • radiation-hydrodynamics of line-driven winds
  • spherical extension

7
LTE vs NLTE
LTE each volume element separately in
thermodynamic equilibrium at temperature T(r)
1. f(v) dv Maxwellian with T T(r) 2. Saha
(np ne)/n1 / T3/2 exp(-h?1/kT) 3. Boltzmann ni /
n1 gi / g1 exp(-h?1i/kT)
However volume elements not closed systems,
interactions by photons ? LTE non-valid if
absorption of photons disrupts equilibrium
8
LTE vs NLTE
NLTE if rate of photon absorptions gtgt rate of
electron collisions I? (T) T?, ? gt 1
ne T1/2
LTE valid low temperatures high
densities non-valid high temperatures low
densities
9
LTE vs NLTE in hot stars
Kudritzki 1978
10
NLTE 1. f(v) dv remains Maxwellian 2. Boltzmann
Saha replaced by dni / dt 0 (statistical
equilibrium) for a given level i the rate of
transitions out rate of transitions in
rate out rate in
i
rate equations Pi,j transition probabilities
11
NLTE
recombination
lines
ionization
lines
Transition probabilities radiative collisional
absorption
emission
Radiative transition probabilities depend on
intensities !!!
12
NLTE 1. f(v) dv remains Maxwellian 2. Boltzmann
Saha replaced by dni / dt 0 (statistical
equilibrium) for a given level i the rate of
transitions out rate of transitions in
rate out rate in
i
rate equations Pi,j transition probabilities
13
complex atomic models for O-stars (Pauldrach
et al., 2001)
14
NLTE Atomic Models in modern model
atmosphere codes lines, collisions, ionization,
recombination Essential for occupation numbers,
line blocking, line force
Accurate atomic models have been
included 26 elements 149 ionization
stages 5,000 levels ( 100,000 ) 20,000 diel.
rec. transitions 4 106 b-b line
transitions Auger-ionization recently
improved models are based on Superstructure

Eisner et al., 1974, CPC
8,270
15
(No Transcript)
16
Recent Improvements on Atomic Data
  • requires solution of Schrödinger equation
  • for N-electron system
  • efficient technique
  • R-matrix method in CC approximation
  • Opacity Project Seaton et al. 1994, MNRAS, 266,
    805
  • IRON Project Hummer et al. 1993, AA, 279,
    298
  • accurate radiative/collisional
    data
  • to 10 on the mean

17
Confrontation with Reality
Photoionization
Electron Collision
Nahar 2003, ASP Conf. Proc.Ser. 288, in press
Williams 1999, Rep. Prog.
Phys., 62, 1431
ü high-precision atomic data ü
18
Improved Modelling for Astrophysics
e.g. photoionization cross-sections for carbon
model atom
Przybilla, Butler Kudritzki 2001b, AA, 379, 936
19
N I/II Model Atom N I 235 levels / 89 terms
757 radiative transitions 210
detailed collisions N II 151 levels / 77 terms
539 radiative transitions 242
detailed collisions Przybilla Butler,
Kudritzki, Becker, 2001
20
LTE vs NLTE departure coefficients - hydrogen
? Orionis (B8 Ia) Teff 12,000 K log g 1.75
(Przybilla 2003)
21
NLTE departure coefficients
biniNLTE/niLTE light a-process
elements overpopulation of metastable
levels Iron Group overionization
Przybilla Butler 2001c, AA, 379, 955
22
LTE vs NLTE line fits nitrogen lines
23
LTE vs NLTE line fits hydrogen lines in IR
Brackett lines
24

log ni/niLTE
FeII
Przybilla, Butler, Kudritzki, Becker, AA, 2005
25
Basic equations
Input
Hydrodyn.
Rateequations
Radiative transfer
energy equation
Non-linear coupling ? complex iteration !!!
26
Dramatic improvements of diagnostics
  • atmospheres millions of metal lines in NLTE
  • Hubeny Lanz ? TLUSTY (no wind)
  • Werner et al. ? Tuebingen-code (no wind)
  • Hillier ? CMFGEN (winds)
  • Pauldrach et al.? WMBasic (winds)
  • Puls et al. ? FASTWIND (winds)
  • Hamann et al. ? Potsdam-code (winds)
  • Hauschildt et al.? Phoenix-code
  • 10m O/IR, FUSE, HST, Chandra, XMM, Spitzer
  • ? enormous potential for quantitative studies

27
HD 93129A O3Ia
Taresch, Kudritzki et al. 1997, AA, 321, 531
28
consistent treatment of expanding atmospheres
along with spectrum synthesis techniques allow
the determination of stellar parameters, wind
parameters, and abundances
Pauldrach, 2003, Reviews in Modern Astronomy,
Vol. 16
29
AV 232 - SMC
Crowther et al. 2002, ApJ, 579, 774
30
Optical spectrum synthesis M33 B-supergiants
M33 UIT103 (B0.7Ia) ESI/Keck II R5000 S/N80
a/H-0.4 dex
Urbaneja, Herrero, Kudritzki et al., 2005, ApJ
635, 311
31
Optical spectrum synthesis A supergiants
32
HRD MW
Model analysis ? Teff vs. sp. Type ? radii,
masses, luminosities ? mass-loss rates,
wind velocities ? chem. Composition ? ioniz.
fluxes
33
3. Parameters and winds of massive stars
  • diagnostic effects of NLTE metal line-blanketing
  • the new Teff-scale of massive stars
  • wind diagnostics with blanketed models
  • winds at low and very low metallicity
  • unsolved problems

34
Massive stars
O I -V
B0-3 I
B4-A3 I
Tracks by Maeder Meynet (with and without
rotational mixing)
35
Metal line-blanketing
  • thousands of strong metal lines absorb flux in
  • outer atmospheric layers ? less flux in UV
  • ? SED,
    ionizing fluxes
  • 50 photons scattered back ? backwarming,
    photosphere
  • hotter,
    ionization equilibr.
  • Teff
    diagnostic
  • dense wind envelopes enhance effects ?
    wind-blanketing

neglected in most of model work until end of last
decade!!
36
Basic equations
Input
Hydrodyn.
Rateequations
Radiative transfer
energy equation
neglect of blanketing in this eq.
37
Metal line-blanketing and local T(t)
log T
--- unblanketed blanketed
log t
38
Metal line-blanketing and Pgas(t)
--- unblanketed blanketed
log P
effective gravity geffg-grad reduced in
blanketed models, larger grad
log t
39
Metal line-blanketing and model flux
log ?3F?
--- unblanketed blanketed
log ?
40
Metal line-blanketing
Trad/Teff
--- unblanketed blanketed
log ?
41
Diagnostics of hot stars
O-stars HeI/II B-supergiants
SiII/III/IV A-supergiants MgI/II OI/II
NI/II SII/III
log g
ionization equilibrium
higher Balmer lines
log Teff
42
Balmer lines, gravity and luminosity
gravity ? atmospheric density ? line
broadening ? Balmer lines
? stellar
luminosities
43
B-supergiant gravity determination
44
O-star spectral types
45
B-star spectral types
SiIII
SiIV
B0Ia
B0.5Ia
B1Ia
B1.5Ia
SiII
B2Ia
B3Ia
B5Ia
B8Ia
B9Ia
46
O-stars
O I -V
Tracks by Maeder Meynet (with and without
rotational mixing)
47
O-star spectral types
48
line blanketing ? HeI/HeI equilibrium ?
Teff O-stars
log W?(HeI4471)/ W?(HeII4542)
-0.2
0.0
-0.7
-0.4
blanketed models ? cooler Teff
shifts depend on metallicity and mass-loss
49
HeI/HeII equilibrium depends also on
log W?(HeI4471)/ W?(HeII4542)
Massey, Puls, Pauldrach, Bresolin, Kudritzki,
Simon, 2005, ApJ 627, 477 Sellmaier, Puls,
Kudritzki, Gabler, Voels, 1993, AA 273, 533
50
metal line blanketing ? H? line strength ?
log g
blanketed models ? higher log g
51
effects of metal line blanketing ionizing fluxes
Z 1.0
Z 10-4
Kudritzki, ApJ 577, 389, 2002
52
effects of metal line blanketing ionizing fluxes
HeII NeII HeI
H
CIII OII
bound-free edges for ionizing photons
Kudritzki, ApJ 577, 389, 2002
53
effects of metal line blanketing ionizing fluxes
H-photons
red with metals blue without
no effects
Kudritzki, ApJ 577, 389, 2002
54
effects of metal line blanketing ionizing fluxes
HeI-photons
red with metals blue without
significant effects
55
effects of metal line blanketing ionizing fluxes
OII-photons
red with metals blue without
huge effects
56
effects of metal line blanketing ionizing fluxes
CIII-photons
red with metals blue without
huge effects
57
effects of metal line blanketing ionizing fluxes
NeII-photons
red with metals blue without
huge effects
58
effects of metal line blanketing ionizing fluxes
HeII-photons
red with metals blue without
huge effects
59
ionizing fluxes dependence stellar wind strength
Teff 30000K
H HeI OII CIII NeII HeII
Kudritzki, ApJ 577, 389, 2002
60
ionizing fluxes dependence stellar wind strength
Teff 50000K
H, HeI OII, CIII NeII
HeII
Kudritzki, ApJ 577, 389, 2002
61
number ofionizing photonspredicted by models
Martins et al., 2005
62
Teff scale of O-stars
  • Galactic O-stars NLTE studies by
  • Pauldrach, Hoffmann, Lennon, 2001, AA
    375, 161
  • Herrero, Puls, Najarro, 2002, AA 396,
    949
  • Martins, Schaerer, Hillier, 2002, AA
    382, 999
  • Bianchi Garcia, 2002, ApJ 581, 610
  • Garcia Bianchi, 2004, ApJ 606, 497
  • Repolust, Puls, Herrero, 2004, AA
    415, 349
  • Markova, Puls, Repolust. Markov, 2004,
    AA 413, 693
  • Martins, Schaerer, Hillier, 2005, AA
  • Mokiem, deKoter, Puls et al., 2005,
    AA 441, 711
  • Bouret, Lanz, Hillier, 2005, AA 438,
    301

10 to 15 cooler than old scale!!!
(Vacca, Garmany, Shull, 1996, ApJ 460, 914)
63
shifts in ( log,Teff ) - plane
  • blanketed models
  • cooler O-stars
  • effects largest
  • at high Teff

Repolust, Puls, Herrero, 2004, AA 415, 349
64
new/old Teff - scales
V, III
I, II
5000 K cooler!!!
Repolust, Puls, Herrero, 2004, AA 415, 349
65
Martins, Schaerer, Hillier, 2004, AA 436, 1049
provides also average luminosities
masses BCs
ionizing fluxes
66
Quantitative infrared H and K band NLTE
spectroscopy of O-stars
  • Galactic O-stars Subaru H and K band high S/N
    spectra
  • Hanson, Kudritzki,
    Kenworthy, Puls, Tokunaga, 2005,

  • ApJS, 161,
    154
  • Repolust, Puls, Hanson,
    Kudritzki, Mokiem, 2005,

  • AA 440,
    261
  • (see also
    Lenorzer et al., 2004, AA 422, 275)
  • excellent agreement with optical spectroscopy
  • Teff , log g, N(He)/N(H),

enormous potential for future work!!! ? higly
dust obscured star forming regions
67
O dwarfs
NIII, V
Hanson, Kudritzki, Kenworthty, Puls, Tokunaga,
2005, ApJS 161, 154 Repolust, Puls, Hanson,
Kudritzki, Mokiem, 2005, AA 440, 261
68
O giants
69
O supergiants
70
Late O, B dwarfs
71
late O, B supergiants
72
O/IR Teff agree
73
O/IR log g agree
74
O/IR mass loss rates agreee
75
Teff metallicity? LMC, SMC
Massey, Bresolin, Kudritzki, Puls, Pauldrach,
2004, ApJ 608, 1001 Massey, Puls, Pauldrach,
Bresolin, Kudritzki, Simon, 2005, ApJ 627, 477
76
SMC O-stars hotter!!
Massey, Bresolin, Kudritzki, Puls, Pauldrach,
2004, ApJ 608, 1001 Massey, Puls, Pauldrach,
Bresolin, Kudritzki, Simon, 2005, ApJ 627, 477
77
MW/SMC Teff - scales
V, III
I, II
Massey et al., 2004, ApJ 608, 1001 Massey et al.,
2005, ApJ 627, 477
78
SMC O-star analysis by Mokiem et al.
AA 2006, in press using VLT-FLAMES
V
III
I
MW dwarfs
See also Martins et al., 2004, AA 420, 1087
79
bolometric correction
BC-6.90logTeff27.99
Massey et al., 2005, ApJ 627, 477 see
also Martins et al., 2005 Heap et al., 2006
80
Teff scale dependence on analysis method ?
  • use of UV metal lines rather than HeI/II only
  • Pauldrach, Hoffmann, Lennon, 2001, AA
    375, 161 ? MW
  • Bianchi Garcia, 2002, ApJ 581, 610
    ? MW
  • Garcia Bianchi, 2004, ApJ 606, 497
    ? MW
  • Crowther, Hillier, Evans, et al.,
    2002, ApJ 579, 774 ? SMC
  • Hillier, Lanz, Heap et al., 2003, ApJ
    588, 1039 ? SMC
  • Evans, Crowther, Fullerton, Hillier,
    2004, ApJ 2004, 610
  • Bouret, Lanz, Hillier, Heap, 2003, ApJ
    595, 1182 ? SMC
  • Bouret, Lanz, Hillier, 2005, AA 438,
    301 MW
  • Martins, Schaerer, Hillier et al.,
    2005, AA 441, 735 MW
  • Heap, Lanz, Hubeny, 2006, ApJ 638, 409
    ? SMC

? cooler than HeI/II scale !!!!
81
UV excited lines of CIII/IV
Heap, Lanz, Hubeny, 2006, ApJ 638, 409
82
Teff vs. FeV/FeIV index
CIII/IV vs. Teff
Heap, Lanz, Hubeny, 2006, ApJ 638, 409
83
fit of optical and UV lines
Heap, Lanz, Hubeny, 2006, ApJ 638, 409
84
SMC HeI/II-scale vs. UV analysis
HeI/II scale Massey et al., 2005
V, III
I, II
85
MW HeI/II-scale vs. UV analysis
V, III
I, II
HeI/II scale Massey et al., 2005
86
The O-star mass discrepancy
2 ways to determine masses method 1
spectral analysis ? Teff, log g
distance, photometry ? radius, luminosity
M gR2 ? mass
method 2 spectral analysis ? Teff
distance, photometry ? radius,
luminosity
stellar evolution HRD ? mass
87
HRD after spectral analysis
Location in HRD use evol. Tracks ? stellar mass
88
The O-star mass discrepancy
2 ways to determine masses method 1
spectral analysis ? Teff, log g
distance, photometry ? radius, luminosity
M gR2 ? mass
method 2 spectral analysis ? Teff
distance, photometry ? radius,
luminosity
stellar evolution HRD ? mass
89
Disagreement between 2 methods
Herrero, Kudritzki et al., 1992 evolutionary
masses much larger
90
Blanketed models HRD LMC/SMC
Mokiem et al., 2005, 2006
LMC
SMC
91
2 methods MW
92
2 methods LMC
93
2 methods SMC
94
Early/mid B supergiants
B0-3 I
95
B-supergiants in M33, optical fit
(Keck/ESI)
M33 UIT103 (B0.7Ia) ESI/Keck II R5000 S/N80
a/H-0.4 dex
Urbaneja, Herrero, Kudritzki et al., 2005, ApJ
635, 311
96
M33 0755 A1-A2 I ISIS/WHT R5000
97
UV fits SMC B-supergiants, Evans et al., 2004
98
UV fits MW B-supergiants, Crowther et al., 2006
99
Teff -scale of BIa supergiants
old
new
Crowther, Lennon, Walborn 2006, AA
446, 279 Trundle, Lennon, 2005,AA 434,
677 Trundle, Lennon et al., 2004, AA
Lennon, 1997, AA 317, 871 metallicity
independent classification
100
bolometric correction
BC-5.13logTeff20.15
101
late B, early A supergiants
B4-A3 I
102
Przybilla, Butler, Kudritzki, Becker, AA, 2006
Spectrum synthesis
103
Teff -scale of B8-A4 Ia supergiants
Kudritzki, Bresolin, Przybilla, 2003,
ApJ Letters, 582, L83 See also Evans
Howarth, 2003,
MNRAS 345, 1223
104
Winds of massive stars
all massive hot stars with L/Lsun gt 104
? highly supersonic,
strong winds basic properties explained
by theory of line driven winds Kudritzki
Puls, 2000, ARAA 38, 613
105
Hydrodynamics of stationary line driven winds
106
Contribution by one line i at ?i
ti
107
line force multiplier
line optical depth
line strength
optical depth parameter
108
depth dependence of line force M(t)
2 extreme cases kmax max
ki, kmin min ki
optical thickness of lines is crucial !
109
line strength distribution function
atomic line lists, NLTE ki for some 106
lines ? power law
Teff 40000 K
a 0.65
see Puls et al. 2000, AAS 141, 23 for detailed
discussion
110
depth dependence of line force
log M(t)
log n(k)
Mmax
slope a - 2
slope -a
log k
log t
ts
kmax 108
111
non-linear eq. of motion
analytic solutions, scaling relations Castor,
Abbott, Klein, 1975 Kudritzki et al. 1989, Puls,
Kudritzki et al., 1996, Kudritzki Puls, 2000
112
Ha fits with hydrodynamic NLTE models
Variation of by 20
Kudritzki Puls, 2000, AARA 38, 613
113
fit of v8 5 accuracy
Kudritzki Puls, 2000, AARA 38, 613
114
Kudritzki Puls, 2000, AARA 38, 613 data from
Prinja Massa (1998), Lamers
et al., (1995)
115
Stellar wind momenta O-stars and CSPN
Kudritzki Puls, 2000 Kudritzki et al., 1997
116
Stellar wind momenta B and A
supergiants
Kudritzki Puls, 2000 Kudritzki et al., 1999
117
WLR for A-supergiants ? distances
Kudritzki et al., 1999 Bresolin et al., 2001
118
Effects of NLTE metal line blanketing
Results shown so far are based on
atmospheric NLTE models with winds
but without metal line
blanketing What are the effects of NLTE metal
line blanketing ???
119
WLR shift to lower luminosities
wind momentum
lower Teff ? lower log L !!
Repolust, Puls, Herrero, 2004, AA 415, 349
Markova, Puls, Repolust, Markov, 2004, AA
120
New WLR O-stars and CSPN
Repolust, Puls, Herrero, 2004 Markova, Puls,
Repolust, Markov, 2004 Kudritzki, Urbaneja, Puls,
2006
121
theoretical wind momenta
observed regressions
calculated
calculations by Kudritzki, 2002, ApJ 577, 389
122
line driven winds calculation of wind
momenta
observed regressions
calculated
calculations by Vink et al., 2002, AA 362, 295
calculations by Kudritzki, 2002, ApJ 577, 389
123
metallicity
log M(t)
log n(k)
Mmax
ZZsun
ZZsun
ZltZsun
ZltZsun
log k
log t
kmax
ts
Abbot, 1982 Kudritzki et al., 1989 Puls,
Kudritzki et al., 1996
124
curvature of line strength distribution function
contribution to M(t) mostly from lines with t
kt 1
log n(k)
real distribution
a-2
a-2
average power law fit
  • for lower metallicity
  • weaker winds
  • larger k contribute
  • a smaller
  • k Z/Zsun
  • distribution shifts
  • a smaller

log k
a smaller !
but no unique exponent !
consequences
125
numerical calculations
Kudritzki et al., 1987 Z/Z_sun
0.1 1.0
Leitherer et al., 1992 Z/Z_sun
0.01 3.0
Vink et al., 2001 Z/Z_sun
0.03 3.0
126
data from Puls Kudritzki, 2000 Crowther et
al., 2002 Hillier et al., 2003, Repolust et al.,
2004 Markova et al., 2004 Evans et al.,
2004 Massey et al., 2004 Massey et al.,
2005 Martins et al., 2004 Bouret et al., 2005
127
data from Puls Kudritzki, 2000 Crowther et
al., 2002 Hillier et al., 2003, Trundle et al.,
2003 2004 Evans et al.,
2004 Massey et al., 2004 Massey et al., 2005
128
O-star wind momenta new MW, LMC, SMC
without wind clumping
LMC
observed
SMC
theory Vink et al., 2001
MW
Mokiem, deKoter, Puls et al. 2006, AA 441, 711
129
O-star wind momenta new MW, LMC, SMC
with wind clumping
LMC
observed
SMC
theory Vink et al., 2001
MW
Mokiem, deKoter, Puls et al. 2006, AA 441, 711
130
WLR theoretical Z dependence
calculations by Vink et al., 2002
calculated
observed SMC regression
calculations by Kudritzki, 2002, ApJ 577, 389
131
B-supergiants wind momenta
Teff gt 23000K agreement with theory lt
23000K disagreement
Crowther, Lennon, Walborn, 2006, AA 446,
279 Trundle Lennon, 2005, AA 627, 477
132
mid-B supergiants
mass-loss theory
Trundle Lennon, 2005, AA 627, 477
mass-loss observed
133
Winds at very low metallicity
theory of line driven winds ? ok for O-stars in
MW, SMC
understand dependence on

luminosity, metallicity etc.
What about very low
metallicity???

Kudritzki, 2002, ApJ 577, 389
134
The first stars in the universe - clues from
hydrodynamic simulations
  • Hydrodynamic simulations by Davé, Katz,
    Weinberg
  • Ly-a cooling radiation (green)
  • Light in Ly-a from forming stars (red, yellow)

z10
z8
z6
135
The first stars - HRD
Bromm, Kudritzki, Loeb, ApJ 552,464 (2001)
136
The first stars - spectra
Bromm, Kudritzki, Loeb, ApJ 552,464 (2001)
137
The first stars integrated cluster light
Bromm, Kudritzki, Loeb, ApJ 552,464 (2001)
138
Stars forming at z10!
1 Mpc (comoving)
As observed through 30-meter telescope R3000,
105 seconds, Barton et al., 2004, ApJ 604, L1
Simulation
139
A possible IMF diagnostic at z10
HeII (l1640 Å) Standard IMF
HeII (l1640 Å) Top-Heavy IMF, zero metallicity
(IMF stellar model fluxes from Bromm,
Kudritzki, Loeb 2001, ApJ 552,464)
140
Winds at very low metallicities a challenge
  • saturation of M(t) at high t
  • kmax t 1
  • ? strong curvature of M(t)
  • ne/W influences curvature
  • ? force multipliers a, d
  • depth dependent

log M(t)
ne/W
log t
new approach needed !!!
141
line driven winds with depth dependent line force
multipliers
For details of numerical of numerical solution
including singularity and regularity conditions
at critical point see
Kudritzki, ApJ 577, 389, 2002
142
wind models for evolved very massive stars
at very low metallicity
  • winds
  • ionizing fluxes
  • spectra

143
the model grid
M/Msun
144
log Mdot vs log Z
M/Msun
300 250 200 150 120 100
not a power law!!!!
analytical formula for Mdot f(L,Z) given
by Kudritzki,2002
Kudritzki, ApJ 577, 389, 2002
145
v8/vesc vs log Z
M/Msun
300 250 200 150 120 100
Kudritzki, ApJ 577, 389, 2002
146
Z/Zsun 1.0 0.2 0.01 0.001 0.0001
wind momentum vs log L
Kudritzki, ApJ 577, 389, 2002
147
effects of metal line blanketing ionizing fluxes
Z 1.0
Z 10-4
Kudritzki, ApJ 577, 389, 2002
148
effects of metal line blanketing ionizing fluxes
HeII NeII HeI
H
CIII OII
bound-free edges for ionizing photons
Kudritzki, ApJ 577, 389, 2002
149
Number of ionizing photonsTeff 50000K, M/Msun
300
Kudritzki, ApJ 577, 389, 2002
150
Teff 50000K, M/Msun 250
Z/Zsun
0.2
10-2
10-4
N V O V
C IV He II
Kudritzki, ApJ 577, 389, 2002
151
Teff 60000K, M/Msun 250
Z/Zsun
0.2
10-2
10-4
N V O V
C IV He II
Kudritzki, ApJ 577, 389, 2002
152
Instabilities
  • a few extremely low Mdot models may suffer from
    de-coupling of
  • H,He and metals (Kudritzki 2002, Krticka et
    al. 2003)
  • ? heating of winds or fallback of material
  • pulsational instabilities important for very
    massive stars, however
  • see Baraffe, Heger Woosley (2001) much
    weaker at low Z
  • rotation ? rotationally induced mass-loss
    (Maeder,Meynet)
  • Meynet, Ekstroem, Maeder
    (2006)
  • Chiappini, Hirschi, Meynet
    et al. (2006)
  • ? very efficient at very
    low Z
  • close to G 1 ? continuum driven winds
  • Shaviv (2001,
    2004)
  • Owocki, Gayley,
    Shaviv (2004)

153
Unsolved problemstellar windclumping
154
Unsolved problems
  • weak wind stars
  • wind clumping

155
Weak wind stars in HRD
Martins, Schaerer, Hillier et al., 2005, AA 441,
735
156
C IV fits for
Martins, Schaerer, Hillier et al., 2005, AA 441,
735
157
Weak wind stars wind momentum
Martins, Schaerer, Hillier et al., 2005, AA 441,
735
158
observed
Martins, Schaerer, Hillier et al., 2005, AA 441,
735
theory
159
possible explanations
  • ionization in UV wrong ? shock emission,
    X-rays, T(r) ?
  • approximations in wind theory? Owocki Puls
    (1999)
  • ion decoupling ? Springmann Pauldrach (1992),
  • Owocki Puls
    (2002), Kudrizki (2002),
  • Krticka et al.
    (2003)
  • different from normal stars? Very young?
  • winds
    not yet developed?

160
effects of stellar wind clumping
line driven winds unstable
see Owocki et al., 1988, ApJ
335, 914
2004, ApJ 616, 525

and references therein ? time
dependent, inhomogeneous, clumping,
filling factors However
amplitude of clumping, filling factors and
clumping length-scales are unknown

161
Radiation hydro simulations snapshot of
density, velocity and

temperature structure
From Runacres Owocki, 2002, AA 381,105
162
The clumping factor
brackets denote temporal averages
100
1
10
r/Rstar
163
Radiative transfer simulation UV wind line
strongly clumped wind Puls, Owocki, Fullerton,
2003, AA 279, 457
  • such profiles are not observed
  • lower clumping amplitude
  • or
  • lower length scale

164
diagnostics of stellar wind clumping
WR- stars very dense winds ?
incoherent electron scattering produces wide
wings of strong emission
lines, effect ?
comparison with ?2 emission lines ? fcl
? clumping diagnostics (Hillier, 1991,
AA 247, 455)
substantial clumping factors fcl
10..20 note diagnostics assume
tiny, optically thin clumps!!!
(many authors, see Crowther, this
meeting)
165
effects of O-star wind clumping
  • O-star winds less dense, no electron
    scattering winds
  • ? diagnostics
    difficult, but
  • tiny HeII 4686 emission time variations

  • (Eversberg et al., 1998)
  • time dependent Discrete Absorption Components
  • in observed UV resonance lines (Howarth
    et al., 1994,
  • Massa et al., 1995,
    Kaper, Henrichs et al., 1994)
  • if substantial clumping exists .

166
effects of O-star wind clumping
? problem for Ha wind diagnostics
of H is minor ionization stage
depends on recombination from H
? ni (H) nEnP ?2 ? t(Ha)wind ?2
? ?clump lt ? gt fcl , fcl density
clumping factor
(observed) (true) (fcl )0.5
167
UV diagnostics of O-star wind clumping
UV resonance lines of dominating ionization
stages tline ? but
most lines saturated ? no reliable diagnostics
however PV resonance
line _at_ 1118 1128 A (FUSE, Copernicus)
is unsaturated wind line with possibly
t(PV)wind ? ? diagnostics
indicating substantial clumping
Hillier et al., 2003, ApJ
588, 1039
Bouret et al. 2003, ApJ 595, 1182
Bouret et al. 2005, ApJ
438, 301
Fullerton et al. 2006, ApJ, in press
168
P V clumping diagnostics of SMC O-star
X(P) 0.23 solar SMC 0.02 solar
0.1 SMC
fcl 1
X(P) 0.23 solar SMC 0.08
solar 0.4 SMC
Hillier et al., 2003, ApJ 588, 1039
fcl 10
169
HD190429A O4 If
Bouret, Lanz, Hillier, 2003, AA 438, 301
170
HD 96715 O4V((f))
Bouret, Lanz, Hillier, 2003, AA 438, 301
171
Fullerton, Massa, Prinja, 2006, ApJ, in press
fitting PV profiles of large sample of O -stars
172
Fullerton, Massa, Prinja, 2006, ApJ, in press
173
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174
Models PV not dominating ionization stage !!!
Teff 46000K
Teff 43000K
model calculations Urbaneja Kudritzki, 2006
175
Models PV not dominating ionization stage !!!
Teff 40000K
Teff 37000K
model calculations Urbaneja Kudritzki, 2006
176
Models PV dominating ionization stage !!!
Teff 34000K
model calculations Urbaneja Kudritzki, 2006
177
Yes!
No!
178
diagnostics of stellar wind clumping
new method for late O-type with Teff lt 37000K He
II is dominant ? ni (He II)
? ionization stage
t(He II)wind ?
? HeII (4686A) ?

Ha ?2 ?
determination of fcl possible
Kudritzki, Urbaneja Puls, 2006
179
PN
Planetary Nebula
central star very hot ? like massive
O-stars
5
180
He2-131 Teff 32000, log g 3.20, y 0.33
H?
He II
He I
He I
181
He2-131 wind lines with fcl 1
calculated HeII 4686 too strong
?fcl gt 1
182
He2-131 wind lines with fcl 1
HeII 4686 ok
?fcl 8
Mdot 1.310-7 Ms/yr
183
He2-108 Teff 34000, log g 3.40, y 0.09
HeII 4686 ok Ha ok
?fcl 1
Mdot 1.410-7 Ms/yr
184
IC 418 Teff 36000, log g 3.20, y 0.17
calculated HeII 4686 too strong
? fcl gt gt 1
185
IC 418 Teff 36000, log g 3.20, y 0.17
fcl 50 !!!!
Mdot 3.710-8 Ms/yr
186
IC418 FUSE PV profile compared fcl 50 model
Kudritzki, Urbaneja, Fullerton Puls, 2006
187
Summary
  • NLTE line blanketed models ?
  • new Teff scale for massive stars
  • new wind momentum luminosity relationship
  • the puzzle of the weak wind stars
  • the role of wind clumping

188
Summary
  • NLTE line blanketed models ?
  • new Teff scale for massive stars
  • new wind momentum luminosity relationship
  • the role of wind clumping

189
(No Transcript)
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