Hipparcos Contribution to Binary Evolution Research

Abstract

The Hipparcos space mission is one of the most fascinating experiment in astrometry never realised. Its importance from a general point of view has not to be recalled but it may be interesting to here examine the part it might have for double star astronomy and more precisely for our research on the evolution of the binaries.In this introductory lecture, we first recall the theories that have been proposed in the past and how we to-day may consider the problem on the basis of our present knowl- edge from a somewhat personal point of view. In that respect we shall here consider the histogram of the real separations of the components, the period-eccentricity relation, the mass-ratio distribution and the HR diagram for binaries. The evolution by secular mass- loss is finally considered with its different possible consequences.Finally the Hipparcos contribution to binary star evolution is discussed on the basis of the different output of the satellite, as the positions (absolute and relative), the parallaxes, the proper motions, the photometric data and the discovery of new systems.From a personal point of view, it appears that beside the parallaxes (the original duty of the mission), the most important result of the satellite is the discovery of new systems due to the general survey of the sky by the mission as well as the photometric data that will be provided for the individual components of the close pairs.KeywordsProper MotionBinary StarMonthly NoticeClose PairDouble StarThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.