Massive star feedback

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Massive star feedback from the first stars to
the present
Jorick Vink (Imperial College London, UK)
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Outline

• Why predict dM/dt ?
• (as a function of Z?)
• Methods CAK Monte Carlo
• Results OB, 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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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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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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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
STAR
Fe

• dM/dt f (L, Mass, Temp, Z)

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1. CAK Formalism
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1. CAK Formalism
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1. CAK Formalism
? dM/dt V(r)
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1. CAK Formalism
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Momentum problem in O star winds
A systematic discrepency
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2. Monte Carlo approach
(Abbott Lucy 1985)
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Assumptions in line-force models

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

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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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Monte Carlo Mass loss comparison
(Vink et al. 2000)
No systematic discrepency anymore !
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Wind momentum-Luminosity relation O stars
(Vink et al. 2000)
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B Supergiants Wind-Momenta
Vink et al. (2000)
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The mass loss of LBVs
Vink de Koter (2002)
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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
• ? Monte Carlo mass-loss used in stellar
  models in Galaxy

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dM/dt f(Z) potential effects

• In CAK dM/dt proportional to k f(Z)
• Power-law exponent log(dM/dt) m log(Z)
• More ionization changes? (bi-stability)
• Power-law for all Z?
• Power-law flattening?

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

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Which metals are important?
solar Z
Fe
CNO
H,He
low Z
At lower Z Fe ? CNO
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Z-dependence of WR winds
Vink de Koter (2005) astro-ph/0507352
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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
• Compute Mdot at Z0
• Wind Clumping
• Wind geometry at low Z

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(No Transcript)
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2-step Approach

• Compute model atmosphere, ionization
  stratification, level populations
• Monte Carlo to compute radiative force (line and
  continuum opacity)

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The bistability Jump
? dM/dt increases by factor 5 ? Wind Density by
factor 10
(Vink et al. 1999)
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Mass loss Recipe
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Consistent mass-loss rate
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Non-consistent velocity law
WC8
Beta 1
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The First Stars
Credit V. Bromm
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Why predict Mdot ?

• Stellar evolution
• - X-ray populations in galaxies
• - Gamma-ray bursts
• Stellar spectra ionizing fluxes
• - Analyses of galaxy spectra
• - Reionization of Universe
• Energy Momentum input into ISM