Some Considerations in making full Use of the Hipparcos Catalogue

TL;DR

This paper provides a practical guide for non-experts on effectively using the Hipparcos Catalogue, discussing error sources, data interpretation, bias correction, and statistical considerations in astrometric data analysis.

Contribution

It offers a comprehensive overview of how to properly utilize Hipparcos data, including error analysis, bias correction, and statistical methods, which was lacking in prior literature.

Findings

Hipparcos Catalogue currently shows no identified systematic errors.

Guidelines for interpreting parallaxes in terms of stellar distances and luminosities.

Methods for accounting for error covariances and correlations in astrometric data.

Abstract

This contribution is intended as a `rough guide' to the Hipparcos Catalogue for the non-expert user. Some general aspects of the use of astrometric data are discussed as well as Hipparcos-specific applications. We discuss when and at what level one may expect systematic errors to occur in the Hipparcos Catalogue. Next we discuss the question of the interpretation of the measured parallaxes in terms of distances and luminosities of stars. What are the biases one should be aware of and how can these be corrected? When using the astrometric data to study the statistics of stars one should take the full covariance matrix of the errors on the astrometric parameters into account. We explain how to do this and discuss the specific case of a moving cluster. Finally, we address the question of the correlation of astrometric parameters over a given region of the sky. At present the Hipparcos Catalogue contains no identified systematic errors.