J/ApJ/743/24 Solar models with accretion. I. (Serenelli+, 2011) ================================================================================ Solar models with accretion. I. Application to the solar abundance problem. Serenelli A.M., Haxton W.C., Pena-Garay C. =2011ApJ...743...24S ================================================================================ ADC_Keywords: Sun ; Models Keywords: accretion, accretion disks - neutrinos - Sun: abundances - Sun: helioseismology - Sun: interior Abstract: We generate new standard solar models using newly analyzed nuclear fusion cross sections and present results for helioseismic quantities and solar neutrino fluxes. The status of the solar abundance problem is discussed. We investigate whether nonstandard solar models with accretion from the protoplanetary disk might alleviate this problem. We examine a broad range of models, analyzing metal-enriched and metal-depleted accretion and three scenarios for the timing of accretion. Only partial solutions are found. For metal-rich accreted material (Z_ac_>~0.018) there exist combinations of accreted mass and metallicity that bring the depth of the convective zone into agreement with the helioseismic value. For the surface helium abundance, the helioseismic value is reproduced if metal-poor or metal-free accretion is assumed (Z_ac_<~0.09). In both cases a few percent of the solar mass must be accreted. Precise values depend on when accretion takes place. We do not find a simultaneous solution to both problems but speculate that changing the hydrogen-to-helium mass ratio in the accreted material may lead to more satisfactory solutions. We also show that, with current data, solar neutrinos are already a very competitive source of information about the solar core and can help constraining possible accretion histories. Even without helioseismic constraints, solar neutrinos rule out the possibility that more than 0.02M_{sun}_ from the protoplanetary disk were accreted after the Sun settled on the main sequence. Finally, we discuss how measurements of neutrinos from the CN cycle could shed light on the interaction between the early Sun and its protoplanetary disk. Description: The new standard solar model (SSM) calculations presented here were done with GARSTEC (Weiss & Schlattl 2008Ap&SS.316...99W), including the updates and modifications in the input physics described in Serenelli et al. (2009ApJ...705L.123S). The new models, in addition, adopt the nuclear reaction rates that were recently recommended in SFII (Solar Fusion II; Adelberger et al. 2011RvMP...83..195A). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table5.dat 150 291 Main properties of solar models including accretion -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 A4 --- Model Model (E1 to L95) (1) 6- 7 I2 Myr tauacc Time when accretion begins (5, 15 or 30) 9- 15 E7.2 Msun Macc Accreted mass 17- 22 F6.4 --- Zacc [0/1] Metallicity of accreted matter 24- 29 F6.4 --- Yacc [0/1] Helium mass fraction of accreted matter 31- 36 F6.4 --- Zini [0/1] Initial metallicity 38- 43 F6.4 --- Yini [0/1] Initial helium mass fraction 45- 50 F6.4 --- aMLT Mixing Length Parameter {alpha}_MLT_ 52- 57 F6.4 --- Zs [0/1] Final surface metallicity 59- 64 F6.4 --- Ys [0/1] Final surface helium mass fraction 66- 71 F6.4 Rsun Rcz Depth of convective envelope 73- 78 F6.4 --- Average rms of relative sound speed difference <{delta}c/c> 80- 85 F6.4 --- Zc [0/1] Central metallicity Z_c_ 87- 92 F6.4 --- Yc [0/1] Central helium mass fraction Y_c_ 94- 98 F5.2 MK Tc Central temperature T_c_ 100-104 F5.1 g/cm3 rho.c Central density {rho}_c_ 106-110 F5.3 10+10/cm2/s pp neutrino flux from pp reaction 112-116 F5.3 10+8/cm2/s pep neutrino flux from pep reaction 118-122 F5.3 10+9/cm2/s Be7 neutrino flux from ^7^Be 124-129 F6.3 10+8/cm2/s B8 neutrino flux from ^8^B 131-136 F6.3 10+8/cm2/s N13 neutrino flux from ^13^N 138-143 F6.3 10+8/cm2/s O15 neutrino flux from ^15^O 145-150 F6.2 --- chi2 Global {chi}^2^ for neutrino fluxes -------------------------------------------------------------------------------- Note (1): Selected models (table 4; see paper for AGSS09 values): ---------------------------------------------------------------------------- Solar GS98 Early accr. Interm. accr. Late accr. E10 E100 I10 I98 L4 L78 L56 ---------------------------------------------------------------------------- M_ac_ --- --- 0.0600 0.0600 0.0600 0.0360 0.0067 0.0360 0.0180 Z_ac_ --- --- 0.0000 0.0300 0.0000 0.0300 0.0000 0.0180 0.0093 Y_ac_ --- --- 0.2710 0.2523 0.2850 0.2374 0.2838 0.2205 0.2837 Z_ini_ --- 0.0187 0.0169 0.0128 0.0196 0.0111 0.0180 0.0093 0.0185 Y_ini_ --- 0.2724 0.2664 0.2568 0.2794 0.2421 0.2787 0.2224 0.2810 a_MLT_ --- 2.161 2.106 2.210 2.021 2.289 2.111 2.266 2.097 Z_s_ 0.0168 0.0170 0.0134 0.0135 0.0132 0.0137 0.0132 0.0141 0.0131 Y_s_ 0.2485 0.2429 0.2352 0.2274 0.2459 0.2147 0.2477 0.1952 0.2498 R_CZ_ 0.713 0.712 0.727 0.719 0.734 0.713 0.726 0.716 0.727 --- 0.0009 0.0053 0.0018 0.0083 0.0025 0.0030 0.0068 0.0035 Z_c_ --- 0.0200 0.0181 0.0137 0.0210 0.0074 0.0193 0.0099 0.0199 Y_c_ --- 0.6333 0.6230 0.6158 0.6337 0.5681 0.6366 0.5769 0.6388 T_c_ --- 15.62 15.57 15.39 15.74 14.87 15.71 14.99 15.75 rho_c_ --- 151.4 148.3 151.6 148.5 146.3 151.4 144.6 151.5 pp 6.05 5.98 6.01 6.07 5.93 6.10 5.94 6.17 5.93 pep 1.46 1.44 1.44 1.51 1.39 1.52 1.42 1.55 1.41 ^7^Be 4.82 5.00 4.76 4.33 5.22 3.85 5.18 3.30 5.27 ^8^B 5.00 5.58 5.09 4.06 6.19 3.21 6.01 2.36 6.25 ---------------------------------------------------------------------------- Notes: M_ac_ in solar units, R_CZ_ in R_{sun}_, T_c_ in 10^6^K, and rho_c_ in g/cm^3^. Neutrino fluxes are given in units of 10^10^(pp), 10^9^(^7^Be), 10^8^(pep), 10^6^(^8^B). ---------------------------------------------------------------------------- -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 26-Apr-2013