INT Solar models Composition, neutrinos & accretion Aldo Serenelli (MPA)

INT Outline Abundances from solar photosphere 3D-atmosphere model line formation Effects on helioseismology and neutrinos can experiments tell something about Z? Accretion onto the Sun? Surface/core composition difference

INT Revision of solar abundances Solar atmosphere: convection  3-D models Improved atomic and molecular trans. prob. Relaxation of LTE assumption

INT Solar atmosphere Credit: N. Brummell 1D models do not capture basic 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

INT D 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 benchmark effects on 3D may be different However… it looks good Credit: Bob Stein

INT D models – testing the model Good handle on granulation topology timescales convective velocities intensity brightness contrast Credit: Bob Stein

INT D models – testing the model Line shapes: bisectors Asplund et al. 2000

INT D models – testing the model Limb darkening Credit: Matt Carlsson Asplund et al. 2009

INT D models – testing the model Other models CO 5 BOLD (aka Paris group) Max Planck for Solar System Research (coming from solar MHD) Ludwig et al Comparison of structure between models undergoing (slowly)

INT Asplund et al D background model atmosphere  detailed radiation transfer for line formation  determination of abundances 3D models – line formation

INT D models – line formation Formal requirement: 3D background model + 3D-RT and 3D-NLTE In practice 3D-RT + 3D-NLTE only for O Different combinations 3D-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

INT D models – line formation Pros: identification of blends Asplund et al But be aware of inconsistent treatment of lines in blends e.g. [OI] and Ni

INT D models – line formation Pros: consistency (after some massage), e.g. atomic and molecular (very T sensitive) indicators Asplund et al. 2009

INT D models – line formation Agreement with meteoritic abundances Asplund et al Si used as reference  = dex

INT D 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

INT Effect on solar models: Helioseismology Reduction in CNONe (30-40%)  boundary in R CZ Reduction in Ne + Si, S, Fe (10%)  Y S Sound speedDensity Z/X= (GS98), (AGSS09)

INT Effect on solar models: Helioseismology Esti mat ion of uncertainties in sound speed and density from MC simulations (5000 models) Density profile: excellent example of correlated differences AGS05

INT Effect on solar models: Helioseismology Low degree modes (l=0, 1, 2, 3) from days BiSON Separation ratios Enhance effects in the core

INT Effect on solar models: Helioseismology

INT Effect on solar models: Helioseismology GS98 models AGS05 models  e averaged over R < 0.2R  Both compositions  e = 0.723±0.003 Chaplin et al. (2007)

INT Effect on solar models: Helioseismology Christensen-Dalsgaard (2009)

INT Effect on solar models: neutrino fluxes Direct measurements of 7 Be and 8 B from Borexino and SNO

INT Effect on solar models: neutrino fluxes Gonzalez-Garcia et al. arxiv: 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

INT Effect on solar models: neutrino fluxes Luminosity constraintNo luminosity constraint No Borexino Borexino

INT Effect on solar models: neutrino fluxes Gonzalez-Garcia et al. arxiv: GS98 AGS05 P(GS98) = 43% P(AGS05)= 20%

INT Effect on solar models: neutrino fluxes GS98 AGS05 AGS09  2 = 5.2 (74%) 5.7 (68%) 5.05 (76%) Is comparison fair?

INT Additional motivation to measure CN fluxes Solar vs. solar twins ( Melendez et al. 2009, Ramirez et al ) same Teff, same gravity, same Fe abundance  same systematics  differential study

INT Additional motivation to measure CN fluxes Volatiles Refractories (V/R)  ~ dex > (V/R) twins IF evidence for accretion after planet formation  solar interior  solar twins interior ≠ surface (eg AGS09)

INT Additional motivation to measure CN fluxes Twins composition Transition “Solar comp.” (V/R) dex contrast between interior and surface in addition to overall Z contrast CN fluxes affected linearly Accretion: schematic composition stratification

INT Conclusions Abundances 3D atmosphere models big step forward line formation still mostly 1D NLTE effects: sometimes, not in 3D atm. model inconsistent treatment of different elements and lines systematics not well understood different groups – different results (abundances and errors) Solar models: helioseismology nothing fits in low-Z models different constraints sensitive to different abundances Solar models: neutrinos current experiments do not discriminate between Z CN measurement needed test of accretion?