UTILISATION OF HIPPARCOS DATA FOR DISTANCE DETERMINATIONS: ERROR, BIAS AND ESTIMATION X. Luri

The Hipparcos astrometric data will allow the determination of a great number of stellar distances. To make a good use of their high accuracy the data have to be used with care to obtain unbiased distance estimations. We discuss in this paper the effects of the observational errors and observational selection criteria on the estimation of distances and we analyse them from a mathematical point of view. Examples are presented using Monte Carlo simulated samples. Key words: barium stars; luminosity calibration; stellar kinematics. 1. INTRODUCTION The goal of the poster presented in the Venice symposium under this title was to illustrate the problems associated with the estimation of distances using trigonometric parallaxes. These difficulties were encountered and highlighted in several presentations and the need for some guidelines on the use of the Hipparcos data was made clear. To cover this need, the inclusion of a `rough guide' to the use of Hipparcos data in these proceedings was d..