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Nicolas GREVESSE*

The Chemical Composition of the SUN. Nicolas GREVESSE* Centre Spatial de Liège and Institut d´Astrophysique et de Géophysique, Université de Liège, Belgium. *Corresponding Astronomer of the Royal Observatory of Belgium, Brussels. New Solar Chemical Composition.

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Nicolas GREVESSE*

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  1. The Chemical Composition of the SUN Nicolas GREVESSE* Centre Spatial de Liège and Institut d´Astrophysique et de Géophysique, Université de Liège, Belgium *Corresponding Astronomer of the Royal Observatory of Belgium, Brussels

  2. New SolarChemical Composition Martin ASPLUND – Max-Planck-Institut für Astrophysik – Garching- Germany A. Jacques SAUVAL – Observatoire Royal de Belgique - Brussels Pat SCOTT - Dept. of Physics – Stockholm University - Sweden M. Asplund, N. Grevesse, A.J. Sauval, P. Scott, Annual Rev. Astron. Astrophys. 47, 481, 2009

  3. Re-determination of the abundances of nearly all availableelements • BASIC INGREDIENTS • New 3D model instead of the classical 1D model of the • lower solar atmosphere • Careful and very demanding selection of the spectral • lines… AVOID blends!!! NOT TRIVIAL!!! • Careful choice of the atomic and molecular data • NOT TRIVIAL!!!! • NLTE instead of the classical LTE hypothesis… • WHEN POSSIBLE !!! • Use of ALL indicators (atoms as well as molecules,CNO)

  4. END RESULT: a COMPREHENSIVEandHOMOGENEOUSre-determination of the abundances of nearly all the elements in the sun. Wealso compare our new photosphericresultswithotherphotospheric data, with data fromothersolar sources …, meteorites and the SolarNeighborhood

  5. j i HOW ? Absorption depends on ratio κline/κcont i.e. ÷(Nel/NH) • Ni* x Aji (or gfij-values) • Physical processes (LTE-NLTE) • Physical conditions :T,P=f(z)…Model Iline(W)depends * Number of atoms or ions that are in the level i

  6. NLTE – both radiative and collisional processes contribute to the excitation and ionization. We have therefore to know the data (transition probabilities, ….) for all the radiative processes that populate and depopulate the level i as well as the cross-sections for all the collisional processes (collisions with electrons, rather well known in a few cases, but also with the neutral hydrogen atoms, very uncertain, from an old formula by Drawin) Data available for very few elements!!! Physical Conditions: LTE versus NLTE

  7. 1D solar atmosphere models • Theoretical models: • Hydrostatic • Time-independent • 1-dimensional • Convection a la mixing length • theory • LTE • Detailed radiative transfer • MARCS, Kurucz etc • Semi-empirical models: • Temperature structure from • observations • Holweger-Müller (1974)

  8. Models have to take the effect of convection into account: the GRANULES (dimensions : 1000-3000 km, lifetime : 10 min)

  9. Hydrodynamics …

  10. … are coupledwithtransfer of radiation along various directions  (6000*6000*3600km; ~10 granules; Stein & Nordlund 1998)

  11. Padova - November 21, 2007

  12. Balance 1D-3D Various ways to test models Q : Does the model reproduce … ? • Test 1D 3D • Ic=F() YesYes • C/L variation No Yes • H line profiles No Yes • Granulation No Yes • Widths of lines Yes* Yes • Shifts of lines No Yes • Asymmetries No Yes • ≠ indicators No Yes • Dependence I,EExNo Yes • High freq oscillations No Yes * Thanks to fake parameters: micro- and macroturbulence

  13. Center to limb variations of Ic versus 

  14. 3D successes ! (continued) • Topology and convective motions For the first time, line profiles are perfectly reproduced • But computing time !

  15. SHAPES of the LINES • Observations : All line profiles* show … • Widths much larger than thermal widths • (with 1D models…microturbulence!!!) • centerblueshifted (2 mA ~ 100 m/s at 600 nm) • Asymmetries (C shapes : ~ 300 m/s i.e. 6 mA) * NON BLENDED LINES, of course

  16. 1-Averaged line profiles 1D vs Sun 3D vs Sun Shift! No micro- and macroturbulence needed in 3D!

  17. 2- Line asymmetries Theasymmetries and shiftsof spectral lines are very well reproduced Observations 3D model

  18. Dependence on Eexc or ionization 1- ATOMS-IONS 3D: perfect agreement FeI - FeII and no dependence on Eexc  FeI  FeII 1D: A(Fe) fromFeIlinesdepends on Eexc and isquitedifferentfrom A(Fe) fromFeIIlines

  19. 2- OH vib-rot lines in IR • Revised solar O abundance: log O=8.69+/-0.03 • Asplund et al. (2009) • 1D : dependence on Eexc • 3D : No trends with line strength or Eexc 3D Holweger-Müller(1D)

  20. Balance 1D-3D Various ways to test models Q : Does the model reproduce … ? NO DOUBT about the REALISM of 3D MODELS • Test 1D 3D • Ic=F() YesYes • C/L variation Yes Yes • Granulation No Yes • Widths of lines Yes* Yes • Shifts of lines No Yes • Asymmetries No Yes • ≠ indicators No Yes • Dependence I,EexcNo Yes • High freq oscillations No Yes * Thanks to fake parameters: micro- and macroturbulence

  21. HT TPICS  Solar O ( recent papers …) Solar Neon? C, N, Mg, Fe, Ar,… Padova - November 21, 2007

  22. Oxygen diagnostics • Discordant results in 1D: log O~8.6-8.9 • Excellent agreement in 3D: log O=8.69+/-0.05 • O isotopic abundances: 16O/18O=480+/-30 *OH lines have the same sensitivity to T as the high Exc O I lines but they are formed higher in the photosphere Padova - November 21, 2007

  23. Beautiful lines - no blends at all - not more sensitive to T than the high excitation (>9eV) O I lines v=1 N=20 v=1 N=20 v=1 N=20 v=0 N=19 v=0 N=19 OH – pure rotation ATMOS solar spectrum from space Padova - November 21, 2007

  24. OH P.R. v ´´= 0 N´´= 25 cm-1 ATMOS solar spectrum Farmer & Norton 1989 Padova - November 21, 2007

  25. O I Lines 3D and NLTE effects * Total equivalent widths (center of the disc) including blends but 2.92 and 1.1 mA when blends are removed Padova - November 21, 2007

  26. O I lines * Level population at 9 eV (permitted lines) is 10-9 of level population in the ground state level (forbidden lines). Padova - November 21, 2007

  27. Forbidden [O I] lines LTE… BUT… 6300 blend with Ni I line 6363 blend with two CN lines 5577 blend with C2 and CN lines We estimated the contributions of the blends independently of any model, in a purely empirical way, from observations of other lines of Ni I, C2 and CN Padova - November 21, 2007

  28. Permitted O I lines High excitation lines LARGE NLTE effects [Δ~-0.25(F) to -0.15(I) dex] Strongly dependent on collisions with H atoms Cross sections not well known* * We estimated them from C/L observations and predictions made with different values of these cross sections Padova - November 21, 2007

  29. Calibration of the cross-sections for collisions with H T.Pereira, M. Asplund, D. Kiselman (2009) Padova - November 21, 2007

  30. Oxygen Results • Discordant results in 1D: log O~8.69-8.86 • Excellent agreement in 3D: log O=8.69+/-0.05 • O isotopic abundances: 16O/18O=480+/-30 If LTE (O I): log O=8.82+/-0.10 [Δ(NLTE)=-0.13 dex] !!! Δ(NLTE) depends strongly on collisions with H atoms Padova - November 21, 2007

  31. O I+[O I]: another 3D analysis(1) • Caffau, Ludwig, Steffen, Ayres, Bonifacio, Cayrel, Freytag, Plez 2008 • O I lines with CO5BOLD:log O = 8.76 ± 0.05 • - Choice of H collisions: log O ≈ -0.03 dex • Equivalent widths:log O ≈ -0.02dex • Weights:log O ≈ -0.02 dex The two 3D models are in very good agreement; abundance results differ by less than 5% 777.1nm 777.4nm 777.5nm Caffau Padova - November 21, 2007

  32. O I+[O I]: another 3D analysis(2) New abundances New equivalent widths+… 8.69 (Caffau) 8.69 (us) 777.1nm New New 777.4nm 777.5nm New Caffau Padova - November 21, 2007

  33. O: 8.76(Caf et al)-8.69(Asp et al)? • Caf et al -0.02 dex for weighting • Caf et al -0.03 dex for NLTE • Caf et al -0.03 dex for equivalent widths and blends for forbidden lines • Total Caf et al -0.08 dex = 8.68 in perfect agreement with us and the low O abundance! Padova - November 21, 2007

  34. Carbon Results • Discordant results in 1D: log C~8.41-8.69 • Excellent agreement in 3D: log O=8.43+/-0.05 • C isotopic abundances: 12C/13C=87+/-4 Padova - November 21, 2007

  35. E. Caffau, H. Ludwig, M. Steffen et al. Large number of C I lines. Many strong IR lines. Shapes indicate blends. Large NLTE, not well known for these lines. Very large dispersion, A(C)=8.50+-0.11, with Min 8.24, Max 8.80 (factor 3.5 !!) Asplund, Grevesse, Sauval & Scott(ARAA) Limited number of fainter lines less sensitive to NLTE. Smaller A(C)=8.43+-0.05 and much smaller dispersion ! Padova - November 21, 2007

  36. Nitrogen Results • 1D: log N=7.97+/-0.08 • 3D: log N=7.83+/-0.05 • 3D-1D= -0.14 dex Caffau et al (2009)7.86+/-0.12 – N I lines BLENDS !!! Padova - November 21, 2007

  37. Solar CNO abundances • 3D solar model atmosphere • Non-LTE line formation when possible • Atomic and molecular lines with improved data • Asplund et al. (2000a,b, 2004, 2005a,b, 2009) Padova - November 21, 2007

  38. Solar CNO abundances • 3D solar model atmosphere • Non-LTE line formation when possible • Atomic and molecular lines with improved data • Asplund et al. (2000a,b, 2004, 2005a,b, 2009) Padova - November 21, 2007

  39. Summary C,N,O Other elements • 3D : Granulation and line profiles • NLTE when possible • All indicators agree • No dependence on I or Eexc …but some increase! (see next slide a comparison New-Old with AG(Grevesse and Anders,1989) ans GS(Grevesse and Sauval,1998) Padova - November 21, 2007

  40. Synergies between solar and stellar modeling, Rome, 22-26 June 2009 Padova - November 21, 2007

  41. These modifications in the abundances are due to the combined effects of…. • New 3D model instead of the classical 1D model of the • lower solar atmosphere • Careful and very demanding selection of the spectral • lines… AVOID blends!!! NOT TRIVIAL!!! • Careful choice of the atomic and molecular data • NOT TRIVIAL!!!! • NLTE instead of the classical LTE hypothesis… • WHEN POSSIBLE !!! • Use of ALL indicators (atoms as well as molecules : CNO) Padova - November 21, 2007

  42. Implications Padova - November 21, 2007

  43. Implications • Significantly lower solar metallicity Z • Z=0.0194 (Anders & Grevesse 1989) • Z=0.0122 (Asplund et al. 2005) Padova - November 21, 2007

  44. New solar metallicity C+N+O ~ 2/3 Z By Mass X+Y+Z=1 X=0.7381 Y=0.2485 Z=0.0134 Z/X=0.0181 Anders, Grevesse 1989 Z=0.019 Z/X=0.027 Grevesse, Noels 1993 Z=0.017 Z/X=0.024 Grevesse, Sauval 1998 By number H  91.3%, He  8.5%,  other elements  0.15% Padova - November 21, 2007

  45. Metallicity Z Padova - November 21, 2007

  46. Implications • Significantly lower solar metallicity Z=0.0122 • Makes Sun normal compared with surroundings • Young O,B stars in solar neighborhood • Local interstellar medium/Orion nebula • Little Galactic Chemical Evolution since 4.5 Gyr ? Padova - November 21, 2007

  47. Implications • Significantly lower solar metallicity Z=0.0122 • Makes Sun normal compared with surroundings • FIP(First Ionization Potential) effect: elements with ionization • potentials smaller than 10 eV are more abundant in the corona Padova - November 21, 2007

  48. FIP:First Ionization Potential Ar Ne Low FIP elements are about a factor 4 more abundant in the Corona than in the photosphere. This factor varies from place to place and with time. Padova - November 21, 2007

  49. Implications • Significantly lower solar metallicity Z=0.0122 • Makes Sun normal compared with surroundings • FIP • Solar NEON ! High or Low? LOW Padova - November 21, 2007

  50. Solar Ne abundance … Ne/O We used Ne/O=0.175 0.031 (Young, 2005; Quiet SUN) ANe = 7.93 0.17 dex (1.5x) smaller than older values • Such ‘low’ Ne/O solar values have been confirmed by • Young (2005) Quiet Sun (EUV, CDS, Soho) • Schmelz et al. (2005) Active regions (X rays) • SEP, SW, Corona at ≠ T Padova - November 21, 2007

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