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Solar modelsComposition, neutrinos & accretion

Aldo Serenelli (MPA)

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Outline

Abundances from solar photosphere3D-atmosphere modelline formation

Effects on helioseismology and neutrinoscan experiments tell something about Z?

Accretion onto the Sun? Surface/core composition difference

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Revision of solar abundances

Solar atmosphere: convection 3-D models

Improved atomic and molecular trans. prob.

Relaxation of LTE assumption

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Solar atmosphere

Credit: N. Brummell

1D models do not capturebasic structure of atmosphere

Energy transported by convection,radiated away at the top

Flow is turbulent

Up- and downward flows asymmetric

Not unique relation T vs. depth

Magnetic fields

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3D models

“Box in a star”: simultaneous solution of radiative transfer (RT) and hydrodynamic equations

RT is “rudimentary”:

frequency dependent opacities combined in a few (4 to 12) bins(10^5 in 1D)

LTE not good opacities (e.g Mg I, Ca I, Si I, Fe I)

1D models used as benchmarkeffects on 3D may be different

However… it looks goodCredit: Bob Stein

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3D models – testing the model

Good handle on granulation

topology

timescales

convective velocities

intensity brightness contrast

Credit: Bob Stein

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3D models – testing the model

Line shapes: bisectors

Asplund et al. 2000

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3D models – testing the model

Limb darkening

Credit: Matt Carlsson

Asplund et al. 2009

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3D models – testing the model

Other models

CO5BOLD (aka Paris group)

Max Planck for Solar System Research (coming from solar MHD)

Ludwig et al. 2010

Comparison of structure between models undergoing (slowly)

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Asplund et al. 2009

3D background model atmosphere

detailed radiation transfer for line formation

determination of abundances

3D models – line formation

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3D models – line formation

Formal requirement: 3D background model + 3D-RT and 3D-NLTE

In practice

3D-RT + 3D-NLTE only for O

Different combinations3D-RT + 1D-NLTE (e.g. C)Multi 1D + 1D-NLTE (e.g. Fe)1D + 1D-NLTE 1D + LTE

Warning: e- and H collision rates (crucial for NLTE) missing for almost all elements, including C & N

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3D models – line formation

Pros: identification of blends

Asplund et al. 2009

But be aware of inconsistent treatment of linesin blends e.g. [OI] and Ni

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3D models – line formation

Pros: consistency (after some massage), e.g. atomic and molecular (very T sensitive) indicators

Asplund et al. 2009

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3D models – line formation

Agreement with meteoritic abundances

Asplund et al. 2009

Si used as reference

=0.00 +- 0.05 dex

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3D models – last two words of warning

Hydrogen (T sensitive) lines poorly reproduced

Regardless of central values, small uncertainties (too optimistic?)Caffau et al. give systematically larger CNO abundances &uncertainties, x2 for C

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Effect on solar models: Helioseismology

Reduction in CNONe (30-40%) boundary in RCZ

Reduction in Ne + Si, S, Fe (10%) YS

Sound speed Density

Z/X= 0.0229 (GS98), 0.0178 (AGSS09)

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Effect on solar models: Helioseismology

Estimation of uncertainties in sound speed and densityfrom MC simulations (5000 models)

Density profile: excellent exampleof correlated differences

AGS05

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Effect on solar models: Helioseismology

Low degree modes (l=0, 1, 2, 3) from +4700 days BiSON

Separation ratios

r

dr

dr

dc

nr

nrR

nn

nn

nn

nn

0

0,0,1

3,11,13

1,11,

2,10,02

)(

)(

Enhance effects in the core

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Effect on solar models: Helioseismology

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Effect on solar models: Helioseismology

GS98 models

AGS05 models

e averagedover R < 0.2R

Both compositionse = 0.723±0.003

Chaplin et al. (2007)

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Effect on solar models: Helioseismology

Christensen-Dalsgaard (2009)

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Effect on solar models: neutrino fluxes

Direct measurementsof 7Be and 8B from Borexino and SNO

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Effect on solar models: neutrino fluxes

Gonzalez-Garcia et al. arxiv: 0910.4584

Global analysis of solar & terrestrial data

3 flavor-mixing framework

Basic constraints from pp-chains and CNO cicles

Luminosity constraint (optional)

Exhaustive discussion of importance of Borexino

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Effect on solar models: neutrino fluxes

Luminosity constraint

006.0005.0

005.0006.0

014.0

986.0

CNO

pp

L

L

No luminosity constraint

005.0007.0

15.014.0

015.0

98.0

CNO

pp

L

L

No Borexino

Borexino

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Effect on solar models: neutrino fluxes

Gonzalez-Garcia et al. arxiv: 0910.4584

GS98

AGS05

P(GS98) = 43%

P(AGS05)= 20%

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Effect on solar models: neutrino fluxes

GS98 AGS05 AGS092= 5.2 (74%) 5.7 (68%) 5.05 (76%) Is comparison fair?

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Additional motivation to measure CN fluxes

Solar vs. solar twins (Melendez et al. 2009, Ramirez et al. 2009)same Teff, same gravity, same Fe abundance same systematics differential study

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Additional motivation to measure CN fluxes

Volatiles

Refractories

(V/R) ~ 0.05-0.08 dex > (V/R)twins

IF evidence for accretion after planet formation

solar interior solar twins

interior ≠ surface (eg AGS09)

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Additional motivation to measure CN fluxes

Twins composition

Transition

“Solar comp.”

(V/R) 0.05-0.10 dex contrast between interior and surfacein addition to overall Z contrast

CN fluxes affected linearly

Accretion: schematic composition stratification

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Conclusions

Abundances3D atmosphere models big step forwardline formation still mostly 1DNLTE effects: sometimes, not in 3D atm. modelinconsistent treatment of different elements and linessystematics not well understooddifferent groups – different results (abundances and errors)

Solar models: helioseismologynothing fits in low-Z modelsdifferent constraints sensitive to different abundances

Solar models: neutrinoscurrent experiments do not discriminate between ZCN measurement neededtest of accretion?