IHY Conference “The Sun, the Heliosphere, and the Earth” Bad Honnef, May 14-18 2007
HELIOSEISMOLOGYHELIOSEISMOLOGY
Maria Pia Di Mauro INAF- Istituto di Astrofisica Spaziale e Fisica Cosmica
Rome (Italy)
Maria Pia Di Mauro INAF- Istituto di Astrofisica Spaziale e Fisica Cosmica
Rome (Italy)
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
The story.....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 14-18 2007
Normal Modes Normal Modes Acoustic waves trapped
in resonant cavities p modes
Normal modes n radial orderl harmonic degreemazimuthal order
(Ulrich 1971, Leibacher & Stein 1972)
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
The proof Deubner 1975
The proof Deubner 1975
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
One Million of indipendent modes excited. Each mode with a different tone!!
These data from theSOI/MDI instrument on board the SOHOsatellite
1024x1024 points over visible disk
1-minute cadenceor better
These data from theSOI/MDI instrument on board the SOHOsatellite
1024x1024 points over visible disk
1-minute cadenceor better
Patches of the solar surface oscillate up and downPatches of the solar surface oscillate up and down
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
Mode trappingMode trapping
Eigenfunction oscillates as function of r when
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
HelioseismologyHelioseismology
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 surfaceto 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 14-18 2007
Why helioseismology?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 inhomogeneititiesSolar-terrestrial physics addressed
-Origin of magnetic storms
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
Local Helioseismology•Structure and dynamics of pieces of the solar interior & changes with time•Travel time of running sound waves
Helioseismic MethodsHelioseismic 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 14-18 2007
Notable Successes of Helioseismology
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 14-18 2007
HELIOSEISMIC APPROACHESHELIOSEISMIC APPROACHES
Model Observables
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 14-18 2007
ACTUAL SOUND-SPEED DIFFERENCE
ACTUAL SOUND-SPEED DIFFERENCE
SUN-MODEL S
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
Turbulent diffusionTurbulent diffusion
Christensen-Dalsgaard & Di Mauro 2007 in press
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
New solar surface abundancesNew solar surface abundances
Asplund et al. (2004 A&A 417, 751)
Improvements:
Non-LTE analysis
3D atmosphere models
Montalban et al. 2004
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 14-18 2007
RELATIVE DENSITY DIFFERENCESRELATIVE DENSITY DIFFERENCESSUN-MODEL S
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
EQUATION OF STATEEQUATION OF STATE
1
ln
lnad
p
First adiabatic exponent1 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 14-18 2007
EOS in the surfaceEOS in the surfaceDifference between SUN and Model S
MDI data l<1000
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
HELIUM ABUNDANCE IN CZ
Y cannot be directly obtained by spectroscopyY by solar Models matching L Y 0.27-0.28
Now: Helioseismic inversionsREFERENCE DATA Y MHD Y OPAL
Basu & Antia (1995)
HLH 100l 1200
0.24560.007
0.24890.0028
Kosovichev (1996) BBSO 4 l140 0.2320.006 0.2480.006
Richard et al. (1998)
MDI 0 l140 0.2420.002 0.2480.002
Basu (1998) MDI l194 0.25240.0001
0.24880.0001
Di Mauro et al. (2002)
MDI l1000 0.24570.0005
0.25390.0005
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
Internal RotationInternal Rotation
Di Mauro et al. 1998 Howe et al. 2000
rc/R = 0.67 +/- 0.05 (Di Mauro et al 1997)
tachoclinetachocline
Rotation breaks spherical simmetry of Rotation breaks spherical simmetry of the Sun and splits the frequency of the Sun and splits the frequency of oscillationsoscillations
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
The Solar CycleThe 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 14-18 2007
Differences between inversions of data taken at successive times reveal the “torsional oscillation”
MDIOLA0.99 R 0.95 R 0.90 R 0.84 R
TORSIONAL OSCILLATIONSTORSIONAL OSCILLATIONS
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
Torsional oscillations of whole CZ
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. 2002 Science
Maria Pia Di Mauro - IHY Conference Bad Honnef, May 14-18 2007
Tachocline OscillationsTachocline OscillationsHowe 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 14-18 2007
ROTATION IN THE COREROTATION IN THE COREMDI 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 14-18 2007
Solar Gravity Modes detected with GOLF!!!Garcia et al. 2007 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 14-18 2007
ConclusionConclusion
•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 14-18 2007
The future…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 14-18 2007
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, 2006Duration: 48 months
Coordinator: Oskar von der Lühe, Kiepenheuer-Institut für Sonnenphysik, Freiburg
European Helio and Asteroseismology
Network
European Helio and Asteroseismology
Network
More information http://www.helas-eu.org
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