Photocentre offset in ultraprecise astrometry: Implications for barycentre determination and asteroid modelling

¹ Rolf Nevanlinna Institute, University of Helsinki, PO Box 4, 00014 Helsinki, Finland
² Observatory, University of Helsinki, PO Box 14, 00014 Helsinki, Finland
³ Observatoire de la Côte d'Azur, Laboratoire Cassini UMR 6529/CNRS, BP 4229, 06304 Nice Cedex 04, France

Corresponding author: M. Kaasalainen, Mikko.Kaasalainen@rni.helsinki.fi

Received: 2 July 2003
Accepted: 1 December 2003

Abstract

We investigate the magnitude and characteristics of the photocentre offset phenomenon of small solar system bodies, and compare different scenarios for correcting for it. We discuss the corresponding implications and limitations to the inverse problem of model construction based on astrometry with instruments such as GAIA.