Abstract | En accompagnement de la mission PICARD dont l'objectif principal était la détermination du diamètre solaire, deux méthodes de détermination du diamètre solaire depuis le sol ont été soutenues par le CNES: PICARSOL et l'analyse des courbes de lumières enregistrées à l'occasion des éclipses solaires totales.
Cette dernière méthode a produit des résultats publiés dans Solar Physics en novembre 2015.
Le poster se propose de présenter une synthèse de ce papier et de faire un premier compte-rendu des observations effectuées à l'occasion de l'éclipse solaire totale du 9 mars 2016 depuis l'Indonésie.
A Novel Technique for Measuring the Solar Radius from Eclipse Light Curves - Results for 2010, 2012, 2013 and 2015-P.Lamy,J.Y.Prado,O.Floyd,P.Rocher,G.Faury,S.Koutchmy.
Abstract:
We report on a novel technique for measuring the solar radius during total solar
eclipses that exploits light curves recorded just before and after second and third contacts.
The measurements are performed by pre-programmed photometers that are deployed
over the eclipse paths and are operated without supervision. The recorded light curves
are compared to synthetic light curves calculated from high-accuracy ephemerides and
lunar-limb profiles constructed from the topographic model of the Moon provided by the
Kaguya lunar space mission. A minimization process between the two sets of curves yields
the solar radius. Altogether, seventeen determinations have been obtained during the past
four total eclipses with the following averages (at a wavelength of 540 nm and scaled to 1 AU): 959.94 ± 0.02 arcsec on 11 July 2010, 960.02 ± 0.04 arcsec on 13 November
2012, 959.99 ± 0.09 arcsec on 3 November 2013, and 960.01 ± 0.09 arcsec on 20 March
2015. Part of the differences between these four values may be attributed to weather conditions.
Averaging the whole set of measurements yields a radius of 959.99 ± 0.06 arcsec
(696,246±45 km), which agrees excellently well with the most recent data and supports an
upward revision of the standard IAU value, as previously suggested. |
