Ground reference for space remote sensing

Laboratory photometry of an asteroid model

¹ Finnish Geodetic Institute, Department of remote sensing and photogrammetry, Geodeetinrinne 2, 02431 Masala, Finland e-mail: Sanna.Kaasalainen@fgi.fi
² Department of Mathematics and Statistics, PO Box 68, 00014 University of Helsinki, Finland e-mail: mjk@rni.helsinki.fi
³ Finnish Geodetic Institute, Department of geodesy and geodynamics, Geodeetinrinne 2, 02431 Masala, Finland e-mail: Jukka.Piironen@fgi.fi

Received: 6 April 2004
Accepted: 25 May 2005

Abstract

We present accurate laboratory CCD photometry of an artificial asteroid sample. The standard inversion method for asteroid lightcurves was implemented to reproduce the measured lightcurves and to derive the global shape, spin state and pole direction to be compared with the known laboratory values. The results imply that the inversion analysis works universally for targets of arbitrary surface composition, i.e., the scattering law does not play a strong role in the analysis. We further investigated the scattering behaviour of the surface material by direct laboratory measurements, and found that the illumination phase angle dependence can be factorized for this material in the same way as for asteroids.