Diapositive 1

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THE PICARD MISSION and ITS SYNERGY WITH THE
HELIOSEISMIC and MAGNETIC IMAGER Gérard
Thuillier1, Judit Pap2, and Sabatino Sofia3
(3) Yale university HAO (2) GSFC JPL
NRL Valencia U
(1) SA (F) IRMB (B) PMOD (Ch) OCA Nice
University IAS LMD
ILWS
CNES has scheduled the launch of PICARD
microsatellite in October 2008.
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PICARD MISSION MAIN SCIENTIFIC OBJECTIVES
(1) Measure the variability of several global
solar properties. In particular, the solar
diameter with a metrological instrument. (2)
Modelling of the solar machine Role of the
magnetic field, on surface or deeper in the
convective zone. (3) Contribution to solar
luminosity reconstruction (4) Long term
trend (5) Understanding of the ground based
measurements
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Key constraints for validating the physics of
solar models are simultanously measured by
PICARD - solar diameter, limb shape,
asphericity in the photosphere - total solar
irradiance - oscillation modes - Temperature
variations in the photosphere ? HMI and
PICARD have a strong synergy
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Photospheric diameter Measurements From ground
observations, there are several optical methods
(Mercury transits, eclipses, astrolabes, imaging
telescope) showing - in phase, or anti phase
with the 11-year solar cycle, or no
variation. ? contradictory results
MDI/SoHO images are used to determine the radius
variation as a function of time. The recent
results show a maximum change of 15 mas per year
(Kuhn et al., 2004). MDI is not a metrological
instrument, as having no internal means to
control the instrument angular scale. Corrections
by models were made.
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DIAMETER VARIATION FROM STRATOSPHERIC BALLOON
OBSERVATIONS Sofia et al. (1994) have built the
Solar Disk Sextant (SDS) using an angular
reference. Operated on board a stratospheric
balloon, several flights were achieved.
Results of four stratospheric balloons flights
carrying SDS (Egidi et al., 2006) showing a
diameter increase of 0.2 while the solar
activity decreases.


SDS Calern
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Sofia et al, 2005
Avec turbulence, diamètre et activité sont en
antiphase
Sans turbulence, diamètre et activité sont en
phase
No turbulence
Sofia et al., 2005
With turbulence
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6 Depth (Mm)
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THE PICARD MISSION MEASUREMENTS In
orbit Diameter, limb shape and asphericity in
the continuum (535, 607, 782 nm). Diameter (215
nm) refered to stars doublets Precision 3 mas
per single image TSI 2 independent radiometers
as on SoHO 5 spectral channels (2 in UV
relevant of ozone photochemistry) Activity
(215 nm, Ca II) Solar oscillations (535
nm) on the ground - diameter, limb shape and
asphericity, - local atmospheric turbulence
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SOHO TSI, images in visible, UV et EUV,
magnetograms, helioseismology. SORCE TSI and
solar spectrum from 12 to 2500 nm. SOLAR B 
X-Rays-X and EUV STEREO CME SOLAR/ISS TSI and
solar spectrum from 17 to 3000 nm. PROBA 2 EUV
image, EUV spectral irradiances SDO EUV,
magnetograms, heliosismologie, images _at_ several
wavelengths PICARD TSI, diameter, asphericity,
helioseismology NPOESS TSI and minor components
concentration measurements.
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SYNERGY HMI/PICARD PICARD will ensure
continuity with SoHO and SORCE for TSI
measurements. Diameter, asphericity, limb
shape in three photospheric spectral
domains Spectral irradiance in UV, visible and
near IR Activity in near UV and CaII
line Temperature variation Helioseismology
measurements (limb, macropixels, and spectral
channels).
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Themes Measurements Instruments
Solar Physics Variability diameter/luminosity, activity, luminosity SODISM I, SOVAP, PREMOS
Asphericity, limb shape SODISM I
Differential rotation SODISM I
Diameter/ stellar reference SODISM I
Helioseismology SODISM I, PREMOS
Climate Diameter/luminosity SODISM I, SOVAP, PREMOS
Luminosity SOVAP, PREMOS
UV Variability PREMOS, SODISM I
Atmospheric Physics Diameter and limb shape at ground Ozone Ground-based instruments (SODISM II, MISOLFA, ) SODISM I, PREMOS
Space Weather Images _at_ 215 and 393 nm (Ca II) SODISM I
SODISM I diameter measurement in orbit. SODISM
II, on ground SOVAP and PREMOS measurement of
the Total Solar Irradiance (TSI) PREMOS
measurement in 5 spectral domains