1. Seismic diagnostics of the equation of state and element abundances in the solar envelope S. V. Vorontsov 1,2, V. A. Baturin 3, S. V. Ayukov 3, V. K. Gryaznov 4 1 Astronomy Unit, Queen Mary, University of London 2 Institute of Physics of the Earth, Moscow 3 Sternberg State Astronomical Institute of Lomonosov Moscow State University 4 Institute of Problems of Chemical Physics RAS, Chernogolovka, Russia

2. Calibration with p-mode frequencies (MDI 15 years)

3. Calibration with p-mode frequencies (MDI 1 year)

5. Inversion for the adiabatic exponent, SAHA-S3

6. Inversion for the adiabatic exponent, SAHA-S5

7. Inversion for the adiabatic exponent, SAHA-S5 mixture OPAL

8. Inversion for the adiabatic exponent, OPAL-2005

9. Effects of heavy elements in the adiabatic exponent

10. Group velocity of surface waves

11. First-order asymtotic description:

12. Inversion with model S Residuals Before and after inversion

13. Inversion for the adiabatic exponent Residuals before the inversion

14. Calibration with group velocities (MDI 1year)

15. Superadiabatic temperature gradient

16. Conclusions SAHA-S equation of state allows to achieve better agreement with seismic data, when compared with OPAL equation of state All our results support the downward revision of solar metallicity. Further work Seismic measurement of C- and O abundances. This will require reduction of systematic errors in frequency measurements, with possible extension of the degree range

18. p-mode frequency data sets SOHO MDI ‘Medium-l’ program (1) 15-years frequency averaging (2) 5-yrs averaging, high activity (3) First year, low solar activity (4) as (3) but with new measurement described in Vorontsov, Jefferies, Giebink, Schou, 2009, Toward Eliminating Systematic Errors in Intermediate-Degree p-Mode Measurements, ASP Conf. Series 416, 301

20. Envelope calibration: blue-data set 1 (15yrs), red-data set 2 (5yr high activity)

21. Envelope calibration: blue-data set 3, red-data set 4 (1yr low activity)

22. Blue: mass coordinate: data set 4 (1yr low activity)

23. Inversion data set 1 (15 years )

24. Inversion: SAHA-S3 data set 1 (15 years )

25. Inversion: Model S data set 1 (15 years )

26. Conclusions Despite of systematic errors, and limitations in degree range, p-mode data allows to compare the performance of modern versions of the equation of state, and allows simultaneous measurement of solar Y and Z values The best agreement with seismic data is provided by the most recent SAHA-S3 equation of state All our results support the downward revision of solar Z value.