Massive star feedback

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Massive star feedback from the first stars to
the present
Jorick Vink (Keele University)
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Outline

• Why predict Mass-loss rates?
• (as a function of Z)
• Monte Carlo Method
• Results OB, Be, LBV WR winds
• Cosmological implications?
• Look into the Future

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Why predict Mdot ?

• Energy Momentum input into ISM

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Massive star feedback
NGC 3603
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Why predict Mdot ?

• Energy Momentum input into ISM

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution

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Evolution of a Massive Star
Be
O
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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Explosions SN, GRBs

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Progenitor for Collapsar model

• Rapidly rotating
• Hydrogen-free star (Wolf-Rayet star)
• But

Woosley (1993)
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Progenitor for Collapsar model

• Rapidly rotating
• Hydrogen-free star (Wolf-Rayet star)
• But
• Stars have winds

Woosley (1993)
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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Explosions SN, GRBs
• Final product Neutron star, Black hole

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Explosions SN, GRBs
• Final product Neutron star, Black hole
• X-ray populations in galaxies

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Stellar Spectra

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Stellar Spectra
• Analyses of starbursts

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Stellar Spectra
• Analyses of starbursts
• Ionizing Fluxes

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Stellar Spectra

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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Stellar Spectra
• Stellar Cosmology

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From Scientific American
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The First Stars
Credit V. Bromm
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The Final products of Pop III stars
(Heger et al. 2003)
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From Scientific American
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Why predict Mdot ?

• Energy Momentum input into ISM
• Stellar Evolution
• Stellar spectra
• Stellar cosmology

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Observations of the first stars
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Goal quantifying mass loss a function of Z (and
z)

• What do we know at solar Z ?

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Radiation-driven wind by Lines
Lucy Solomon (1970) Castor, Abbott Klein
(1975) CAK
Wind
STAR
Fe

• dM/dt f (Z, L, M, Teff)

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Radiation-driven wind by Lines
Abbott Lucy (1985)

• dM/dt f (Z, L, M, Teff)

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Momentum problem in O star winds
A systematic discrepancy
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Monte Carlo approach
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Approach

• Assume a velocity law
• Compute model atmosphere, ionization
  stratification, level populations
• Monte Carlo to compute radiative force

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Mass loss parameter study
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Monte Carlo Mass loss comparison
(Vink et al. 2000)
No systematic discrepancy anymore !
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Lamers et al. (1995) Crowther et al.
(2006)
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Monte Carlo Mass-loss rates
? dM/dt increases by factor 3-5
(Vink et al. 1999)
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The bi-stability Jump

• HOT
• Fe IV
• low dM/dt
• high Vinf
• Low density

• COOL
• Fe III
• high dM/dt
• low Vinf
• High density

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Stars should pass the bistable limit

• During evolution from O ? B
• LBVs on timescales of years

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LBVs in the HRD
Smith, Vink de Koter (2004)
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The mass loss of LBVs
Models
Data
Stahl et al. (2001) Vink de
Koter (2002)
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Stars should pass the bistable limit

• During evolution from O ? B
• LBVs on timescales of years
• Implications for circumstellar medium (CSM)
• Mass-loss rate up 2
• wind velocity down 2
• CSM density variations 4

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SN-CSM interaction ? radio
Weiler et al. (2002)
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Mass Loss Results from Radio SNe
OB star? WR?
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SN 2001ig 2003bg
2003bg
2001ig
Soderberg et al. (2006)
Ryder et al. (2004)
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Progenitors

• AGB star
• Binary WR system
• WR star
• LBV

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Progenitors

• AGB star
• Binary WR system
• WR star
• LBV

Kotak Vink (2006)
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Assumptions in line-force models

• Stationary
• One fluid
• Spherical

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Polarimetry from disks
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Depolarisation
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Asphericity in LBV HR CAR
(Davies, Oudmaijer Vink 2005) SURVEY
asphericity found in 50
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Variable polarization in AG CAR
(Davies, Oudmaijer Vink 2005) ?
RANDOM CLUMPS!!
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Assumptions in line-force models

• Stationary
• One fluid
• Spherical
• Homogeneous, no clumps

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Success of Monte Carlo at solar Z

• O-star Mass loss rates
• Prediction of the bi-stability jump
• Mass loss behaviour of LBVs like AG Car
• ? Monte Carlo mass-loss used in stellar
  models in Galaxy

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O star mass-loss Z-dependence
(Vink et al. 2001)
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O star mass-loss Z-dependence
Kudritzki (2002) --- Vink et al. (2001)
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O star mass-loss Z-dependence

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Which metals are important?
Vink et al. (2001)
solar Z
Fe
CNO
H,He
low Z
At lower Z Fe ? CNO
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WR stars produce Carbon !
Geneva models (Maeder Meynet 1987)
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WR stars produce Carbon !
Geneva models (Maeder Meynet 1987)
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Which element drives WR winds?

• C ? WR mass loss not Z(Fe)-dependent
• Fe ? WR mass loss depends on Z host

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Z-dependence of WR winds
WN
WC
Vink de Koter (2005, AA 442, 587)
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Corollary of lower WR mass loss

• ? less angular momentum loss
• ? favouring the collapse of WR stars to produce
  GRBs
• ? Long-duration GRBs favoured at low Z

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Conclusions

• Successful MC Models at solar Z
• O star winds are Z-dependent (Fe)
• WR winds are Z-dependent (Fe) ? GRBs
• Low-Z WC models flattening of this dependence
• Below log(Z/Zsun) -3 ? Plateau
• ? Mass loss may play a role in early Universe

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Future Work

• Solving momentum equation
• Wind Clumping
• Compute Mdot close to Eddington limit

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Mass loss Eddington Limit
Gamma5
Vink (2006) - astro-ph/0511048
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Future Work

• Solving momentum equation
• Wind Clumping
• Compute Mdot close to Eddington limit
• Compute Mdot at subsolar and Z 0

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From Scientific American
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(No Transcript)
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Non-consistent velocity law
WC8
Beta 1
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Wind momenta at low Z
Data (Mokiem)
Models (Vink)
Vink et al. (2001) Mokiem et al.
(2007)
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Two O-star approaches

• 1. CAK-type
• ? Line force approximated
• ? v(r) predicted
• CAK,
  Pauldrach (1986), Kudritzki (2002)
• 2. Monte Carlo
• ? V(r) adopted
• ? Line force computed for all radii
• ? multiple scatterings included
• Abbott
  Lucy (1985)
• 
  Vink, de Koter Lamers (2000,2001)

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Advantages of our method

• Non-LTE
• Unified treatment (no core-halo)
• Monte Carlo line force at all radii
• Multiple scatterings
• ? O stars at solar Z low Z
• LBV variability WR as a function of Z

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The bi-stability Jump

• HOT
• Fe IV
• low dM/dt
• high V(inf)
• Low density

• COOL
• Fe III
• dM/dt 5 dM/dt HOT
• V(inf) ½ vinf HOT
• High density 10 HOT

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The reason for the bi-stability jump

• Temperature drops
• ? Fe recombines from Fe IV to Fe III
• ? Line force increases
• ? dM/dt up
• ? density up
• ? V(inf) drops
• ? Runaway

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Quantifying the effect of the velocity law
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Can we use our approach for WR stars?

• Potential problems
• Are these winds radiatively driven?
• Is Beta 1 a good velocity law?
• Do we miss any relevant opacities?
• What about wind clumping?

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B Supergiants Wind-Momenta
Vink, de Koter Lamers (2000)
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New Developments

• Hot Iron Bump Fe X --- Fe XVI
• Graefener Hamann (2005) can drive
• a WC5 star self-consistently
• ? Use Monte Carlo approach for a differential
  study of Mass loss versus Z

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The bi-stability jump at B1
Lamers et al. (1995) Pauldrach Puls (1990)