ihy conference “the sun, the heliosphere, and the earth” bad honnef, may 14-18 2007...

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!!!


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)


The proof Deubner 1975

The proof Deubner 1975


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


Mode trappingMode trapping

Eigenfunction oscillates as function of r when


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.


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


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


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


HELIOSEISMIC APPROACHESHELIOSEISMIC APPROACHES

Model Observables

Forward approach

Inverse approach

Aim of inversion: to make inferences about localized properties of the solar interior


ACTUAL SOUND-SPEED DIFFERENCE

ACTUAL SOUND-SPEED DIFFERENCE

SUN-MODEL S


Turbulent diffusionTurbulent diffusion

Christensen-Dalsgaard & Di Mauro 2007 in press


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!!


RELATIVE DENSITY DIFFERENCESRELATIVE DENSITY DIFFERENCESSUN-MODEL S


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


EOS in the surfaceEOS in the surfaceDifference between SUN and Model S

MDI data l<1000


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


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


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


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


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


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


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


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


ConclusionConclusion

•Magnetic fields•EOS •2D model

•Rotation•Convection

•Diffusion•Non adiabatic effects

• Longer series of oscillations data• g modes

Improve model

Observations


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:???


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

ihy conference “the sun, the heliosphere, and the earth” bad honnef, may 14-18 2007...

Documents

solar surface

origin of solar magnetism

solar interior changes

fluid dynamics stellar

basic physics

indipendent modes excited

stellar evolution

dynamics of pieces