IHY Conference “The Sun, the Heliosphere, and the Earth” Bad Honnef, May HELIOSEISMOLOGY Maria Pia Di Mauro INAF- Istituto di Astrofisica Spaziale e Fisica Cosmica Rome (Italy)

Maria Pia Di Mauro - IHY Conference Bad Honnef, May The story..... Periodic Motions P  5 min of the absorption lines of the photospheric spectrum (Leighton et al. 1962) PULSATIONS OF THE PHOTOSPHERE!!!

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Normal Modes Acoustic waves trapped in resonant cavities  p modes Normal modes n radial order l harmonic degree mazimuthal order (Ulrich 1971, Leibacher & Stein 1972)

Maria Pia Di Mauro - IHY Conference Bad Honnef, May The proof Deubner 1975

Maria Pia Di Mauro - IHY Conference Bad Honnef, May One Million of indipendent modes excited. Each mode with a different tone!! These data from the SOI/MDI instrument on board the SOHO satellite 1024x1024 points over visible disk 1-minute cadence or better These data from the SOI/MDI instrument on board the SOHO satellite 1024x1024 points over visible disk 1-minute cadence or better Patches of the solar surface oscillate up and down

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Mode trapping Eigenfunction oscillates as function of r when

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Properties of solar oscillations   Modes are excited stochastically by convection   Periods « τ th  adiabatic approximation   Modes are damped by convective flux and turbulent pressure perturbations   Amplitude  low v r  15 cm/s  <  I  I  10 -6

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Helioseismology Study of oscillations in the Sun in a similar way as geoseismology is the study of earthquakes Study of the solar oscillations observed at the surface to probe the structure and the dynamics of the Sun The technique is very similar to trying to determine the shape of musical instruments from the sound they make.

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Why helioseismology?   Frequencies depend on the structure of the star  (r), p(r),   (r), c(r) but only 2 independent functions: e.g.  (r) and c(r)   Frequencies can be measured with accuracy (10 -5)   Basic physics addressed -Equation of state, opacities, neutrinos, general relativity, fluid dynamics   Stellar physics addressed -Stellar evolution, differential rotation, origin of solar magnetism, nature of spatial and temporal inhomogeneitities   Solar-terrestrial physics addressed -Origin of magnetic storms

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Local Helioseismology Structure and dynamics of pieces of the solar interior & changes with time Travel time of running sound waves Helioseismic Methods Global Helioseismology Structure & dynamics of the longitudinally averaged solar interior & changes with time Frequencies of p modes

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Notable Successes of Helioseismology   Depth of the solar convection zone (Christensen-Dalsgaard 1985)   Opacity   Neutrino Problem   Diffusion of helium and heavy elements (Basu et al. 1996)   Helium abundance   Relativistic effect in the core (Elliot & Kosovichev 1998)   Internal Dynamics

Maria Pia Di Mauro - IHY Conference Bad Honnef, May HELIOSEISMIC APPROACHES ModelObservables Forward approach Inverse approach Aim of inversion: to make inferences about localized properties of the solar interior

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Forward Approach: Comparison MDI l<1000 (Rhodes et al. 1998) and Model S

Maria Pia Di Mauro - IHY Conference Bad Honnef, May ACTUAL SOUND-SPEED DIFFERENCE SUN-MODEL S

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Turbulent diffusion Christensen-Dalsgaard & Di Mauro 2007 in press

Maria Pia Di Mauro - IHY Conference Bad Honnef, May New solar surface abundances Asplund et al. (2004 A&A 417, 751) Improvements:   Non-LTE analysis   3D atmosphere models Montalban et al Grevesse & Noels 1993 Unfortunately this model has a too small CZ and lower He abundance than inferred one!!

Maria Pia Di Mauro - IHY Conference Bad Honnef, May RELATIVE DENSITY DIFFERENCES SUN-MODEL S

Maria Pia Di Mauro - IHY Conference Bad Honnef, May EQUATION OF STATE First adiabatic exponent  1  5/3 in the interior except in the H and He ionization zones   MHD (Mihalas, Däppen & Hummer 1990)- chemical picture Pressure ionization (Partition equation) NonRelativistic Electron degeneracy Excited states Coulomb correction in the Debye-Hückel approximation   OPAL (Rogers, Swenson & Iglesias 1996) - physical picture Pressure ionization Relativistic Electron degeneracy(OPAL2001) Excited states Partition equation and degree of ionization Coulomb correction (many-body quantum physics) Electron exchange Quantum diffraction

Maria Pia Di Mauro - IHY Conference Bad Honnef, May EOS in the interior Inversion of data with l  100 Di Mauro & Christensen-Dalsgaard 2001

Maria Pia Di Mauro - IHY Conference Bad Honnef, May EOS in the surface Difference between SUN and Model S MDI data l <1000

Maria Pia Di Mauro - IHY Conference Bad Honnef, May HELIUM ABUNDANCE IN CZ G GY cannot be directly obtained by spectroscopy G GY by solar Models matching L  Y  Now: Helioseismic inversions REFERENCEDATA Y MHDY OPAL Basu & Antia (1995) HLH 100  l    Kosovichev (1996) BBSO 4  l    Richard et al. (1998) MDI 0  l    Basu (1998)MDI l    Di Mauro et al. (2002) MDI l   

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Internal Rotation Di Mauro et al. 1998Howe et al r c /R = / (Di Mauro et al 1997) tachocline Rotation breaks spherical simmetry of the Sun and splits the frequency of oscillations

Maria Pia Di Mauro - IHY Conference Bad Honnef, May The Solar Cycle  Activity grows and decays over 11 years  Zones of magnetic activity move towards the equator  Bands of slower and faster rotation also migrate, ahead of the magnetic bands Deviations from the mean rotation profile as a function of latitude and time Howe et al. 2000

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Differences between inversions of data taken at successive times reveal the “torsional oscillation” MDI OLA 0.99 R0.95 R 0.90 R 0.84 R TORSIONAL OSCILLATIONS

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Torsional oscillations of whole CZ Differencing rotation inversions at successive 72-day epochs relative to solar minimum (1996) shows equatorward and poleward migration of torsional oscillations Vorontsov et al Science

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Tachocline Oscillations Howe 2006 The rotation rate appears to show quasi-periodic oscillations of 1.3 year period near the base of the convection zone at mid-latitudes

Maria Pia Di Mauro - IHY Conference Bad Honnef, May ROTATION IN THE CORE MDI l < 100 (Schou et al. 1998)+   IRIS l=1-3 (Lazreck et al. 1996; Gizon et al 1997, Fossat 1998)   GONG l=1-3 (Gavryuseva & Gavryuseva 1998)   BISON +LOWL l=1-4 (Chaplin et al. 1999)   GOLF l=1-2 (Corbard et al. 1998) Di Mauro et al. 1998

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Solar Gravity Modes detected with GOLF!!! Garcia et al on Science last week News!!! News!!! 10 years of observations from GOLF Observed g mode is consistent with a model with a rotation rate 3 or 5 times higher than radiative interior

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Conclusion Magnetic fields EOS 2D model Rotation Convection Diffusion Non adiabatic effects Longer series of oscillations data g modes Improve model Observations

Maria Pia Di Mauro - IHY Conference Bad Honnef, May The future… SDO Solar Dynamics Observatory, HMI (local helioseismology) NASA launch: 2008 to understand variation of magnetic fields dynamical processes and solar structure and its impact on Earth SO Solar Orbiter ESA Launch: 2013 VIM (local helioseismology at high latitude) to study, by approaching as close as 45 solar radii, the polar regions and the side of the Sun not visible from Earth PICARD CNES Launch: 2009 PREMOS (low l and g modes) to study of the Earth climate and Sun variability relationship DYNAMICS Dynamics and Magnetism from the Internal core to the Chromosphere of the Sun, Turck-Chieze et al. Saclay, (France) Launch:???

Maria Pia Di Mauro - IHY Conference Bad Honnef, May Co-ordinated Action funded by FP6 the 6th Framework Programme of the European Union Objective: Bringing together the European research groups active in helio- & asteroseismology. Start date: April 1, 2006 Duration: 48 months Coordinator: Oskar von der Lühe, Kiepenheuer-Institut für Sonnenphysik, Freiburg European Helio and Asteroseismology Network More information