Solar Physics

, Volume 290, Issue 10, pp 2617–2648

A Novel Technique for Measuring the Solar Radius from Eclipse Light Curves – Results for 2010, 2012, 2013, and 2015

  • Philippe Lamy
  • Jean-Yves Prado
  • Olivier Floyd
  • Patrick Rocher
  • Guillaume Faury
  • Serge Koutchmy
Article

DOI: 10.1007/s11207-015-0787-8

Cite this article as:
Lamy, P., Prado, JY., Floyd, O. et al. Sol Phys (2015) 290: 2617. doi:10.1007/s11207-015-0787-8

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): \(959.94\pm0.02~\mbox{arcsec}\) on 11 July 2010, \(960.02\pm0.04~\mbox{arcsec}\) on 13 November 2012, \(959.99\pm0.09~\mbox{arcsec}\) on 3 November 2013, and \(960.01\pm0.09~\mbox{arcsec}\) 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 \(959.99\pm0.06~\mbox{arcsec}\) (\(696{,}246\pm45~\mbox{km}\)), which agrees excellently well with the most recent data and supports an upward revision of the standard IAU value, as previously suggested.

Keywords

Sun Sun: diameter Sun: eclipses 

Funding information

Funder NameGrant NumberFunding Note
Centre National d’Etudes Spatiales
  • BC U44 & BC U67

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  • Philippe Lamy
    • 1
  • Jean-Yves Prado
    • 2
  • Olivier Floyd
    • 3
  • Patrick Rocher
    • 4
  • Guillaume Faury
    • 1
    • 3
  • Serge Koutchmy
    • 5
  1. 1.Laboratoire d’Astrophysique de Marseille, UMR 7236CNRS & Aix-Marseille UniversitéMarseille cedex 13France
  2. 2.Centre National d’Etudes SpatialesToulouseFrance
  3. 3.AKKA Informatique et SystèmesToulouse cedex 1France
  4. 4.Institut de Mécanique Céleste et de Calcul des Ephémérides, UMR 8028CNRS & Observatoire de ParisParisFrance
  5. 5.Institut d’Astrophysique de Paris, UMR 7095CNRS & Université Pierre et Marie CurieParisFrance

Personalised recommendations