Solar models Composition neutrinos accretion Aldo Serenelli MPA

Solar models Composition, neutrinos & accretion Aldo Serenelli (MPA) INT - 08. 10

Outline Abundances from solar photosphere 3 D-atmosphere model line formation Effects on helioseismology and neutrinos can n experiments tell something about Z? Accretion onto the Sun? Surface/core composition difference INT - 08. 10

Revision of solar abundances Solar atmosphere: convection 3 -D models Improved atomic and molecular trans. prob. Relaxation of LTE assumption INT - 08. 10

Solar atmosphere 1 D 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 - 08. 10 Credit: N. Brummell

3 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 1 D) LTE not good opacities (e. g Mg I, Ca I, Si I, Fe I) 1 D models used as benchmark effects on 3 D may be different However… it looks good Credit: Bob Stein INT - 08. 10

3 D models – testing the model Good handle on granulation topology timescales convective velocities intensity brightness contrast Credit: Bob Stein INT - 08. 10

3 D models – testing the model Line shapes: bisectors Asplund et al. 2000 INT - 08. 10

3 D models – testing the model Limb darkening Asplund et al. 2009 Credit: Matt Carlsson INT - 08. 10

3 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. 2010 Comparison of structure between models undergoing (slowly) INT - 08. 10

3 D models – line formation 3 D background model atmosphere Asplund et al. 2009 detailed radiation transfer for line formation determination of abundances INT - 08. 10

3 D models – line formation Formal requirement: 3 D background model + 3 D-RT and 3 D-NLTE In practice 3 D-RT + 3 D-NLTE only for O Different combinations 3 D-RT + 1 D-NLTE (e. g. C) Multi 1 D + 1 D-NLTE (e. g. Fe) 1 D + 1 D-NLTE 1 D + LTE Warning: e- and H collision rates (crucial for NLTE) missing for almost all elements, including C & N INT - 08. 10

3 D models – line formation Pros: identification of blends Asplund et al. 2009 But be aware of inconsistent treatment of lines in blends e. g. [OI] and Ni INT - 08. 10

3 D models – line formation Pros: consistency (after some massage), e. g. atomic and molecular (very T sensitive) indicators Asplund et al. 2009 INT - 08. 10

3 D models – line formation Agreement with meteoritic abundances Si used as reference D=0. 00 +- 0. 05 dex Asplund et al. 2009 INT - 08. 10

3 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, x 2 for C INT - 08. 10

Effect on solar models: Helioseismology Reduction in CNONe (30 -40%) boundary in RCZ Reduction in Ne + Si, S, Fe (10%) YS Sound speed Z/X= 0. 0229 (GS 98), 0. 0178 (AGSS 09) INT - 08. 10 Density

Effect on solar models: Helioseismology Estimation of uncertainties in sound speed and density from MC simulations (5000 models) AGS 05 Density profile: excellent example of correlated differences INT - 08. 10

Effect on solar models: Helioseismology Low degree modes (l=0, 1, 2, 3) from +4700 days Bi. SON Separation ratios Enhance effects in the core INT - 08. 10

Effect on solar models: Helioseismology INT - 08. 10

Effect on solar models: Helioseismology GS 98 models me averaged over R < 0. 2 R 8 Both compositions me = 0. 723± 0. 003 AGS 05 models Chaplin et al. (2007) INT - 08. 10

Effect on solar models: Helioseismology Christensen-Dalsgaard (2009) INT - 08. 10

Effect on solar models: neutrino fluxes Direct measurements of 7 Be and 8 B from Borexino and SNO INT - 08. 10

Effect on solar models: neutrino fluxes Gonzalez-Garcia et al. arxiv: 0910. 4584 Global analysis of solar & terrestrial n data 3 flavor-mixing framework Basic constraints from pp-chains and CNO cicles Luminosity constraint (optional) Exhaustive discussion of importance of Borexino INT - 08. 10

Effect on solar models: neutrino fluxes No luminosity constraint No Borexino INT - 08. 10 Luminosity constraint

Effect on solar models: neutrino fluxes Gonzalez-Garcia et al. arxiv: 0910. 4584 GS 98 AGS 05 P(GS 98) = 43% P(AGS 05)= 20% INT - 08. 10

Effect on solar models: neutrino fluxes 2= GS 98 5. 2 (74%) AGS 05 5. 7 (68%) Is comparison fair? INT - 08. 10 AGS 09 5. 05 (76%)

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 INT - 08. 10

Additional motivation to measure CN fluxes (V/R)8 ~ 0. 05 -0. 08 dex > (V/R)twins IF evidence for accretion after planet formation Volatiles solar interior solar twins interior ≠ surface (eg AGS 09) INT - 08. 10 Refractories

Additional motivation to measure CN fluxes Accretion: schematic composition stratification “Solar comp. ” Transition Twins composition INT - 08. 10 (V/R) 0. 05 -0. 10 dex contrast between interior and surface in addition to overall Z contrast CN fluxes affected linearly

Conclusions Abundances 3 D atmosphere models big step forward line formation still mostly 1 D NLTE effects: sometimes, not in 3 D 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? INT - 08. 10