HELIOSEISMOLOGY. Maria Pia Di Mauro INAF- Istituto di Astrofisica Spaziale e Fisica Cosmica Rome (Italy). 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.
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IHY Conference “The Sun, the Heliosphere, and the Earth” Bad Honnef, May 14-18 2007
Periodic Motions P 5 min
of the absorption lines of the photospheric spectrum
(Leighton et al. 1962)
PULSATIONS OF THE PHOTOSPHERE!!!
Acoustic waves trapped
in resonant cavities p modes
(Ulrich 1971, Leibacher & Stein 1972)
n radial order
l harmonic degree
These data from the
on board the SOHO
over visible disk
One Million of indipendent modes excited. Each mode with a different tone!!
Eigenfunction oscillates as function of r when
to probe the structure and the dynamics of the Sun
Study of oscillations in the Sun in a similar way as geoseismology is the study of earthquakes
The technique is very similar to trying to determine the shape of musical instruments from the sound they make.
-Equation of state, opacities, neutrinos, general relativity, fluid dynamics
-Stellar evolution, differential rotation, origin of solar magnetism, nature of spatial and temporal inhomogeneitities
-Origin of magnetic storms
Aim of inversion: to make inferences about localized properties of the solar interior
Christensen-Dalsgaard & DiMauro 2007 in press
Grevesse & Noels 1993New solar surface abundances
Asplund et al. (2004 A&A 417, 751)
Unfortunately this model has a too small CZ and lower He abundance than inferred one!!
Montalban et al. 2004
First adiabatic exponent
1 5/3 in the interior
except in the H and He ionization zones
Difference between SUN and Model S
MDI data l<1000
Rotation breaks spherical simmetry of the Sun and splits the frequency of oscillations
Howe et al. 2000
rc/R = 0.67 +/- 0.05 (Di Mauro et al 1997)
Deviations from the mean rotation profile as a function of latitude and time Howe et al. 2000The Solar Cycle
TORSIONAL OSCILLATIONS latitude and time Howe et al. 2000
Differences between inversions of data taken at
successive times reveal the “torsional oscillation”
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
The rotation rate appears to show quasi-periodic oscillations of 1.3 year period near the base of the convection zone at mid-latitudes
Di Mauro et al. 1998
News!!! latitude and time Howe et al. 2000
10 years of observations from GOLF
Solar Gravity Modes detected with GOLF!!!
Garcia et al. 2007 on Science last week
Observed g mode is consistent with a model with a rotationrate 3 or 5 times higher than radiative interior
PICARD latitude and time Howe et al. 2000CNES Launch: 2009 PREMOS (low l and g modes) to study of the Earth climate and Sun variabilityrelationship
SO Solar OrbiterESA 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 EarthThe future…
SDO Solar Dynamics Observatory, HMI (local helioseismology)NASA launch: 2008 tounderstand variation of magnetic fields dynamical processes and solar structureand its impact on Earth
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
More information http://www.helas-eu.org