7 papers · 1 filter
Gaia First Look
S. Jordan, U. Bastian, H. Lenhardt +3
A complicated and ambitious space mission like Gaia needs a careful monitoring and evaluation of the functioning of all components of the satellite. This has to be performed on dif…
A Finding List for Delta_mu Binaries derived from a Comparison of HIPPARCOS Proper Motions with Long-term Averaged Data
Roland Wielen, Christian Dettbarn, Hartmut Jahreiss +3
The comparison of quasi-instantaneously measured HIPPARCOS proper motions with long-term averaged proper motions, derived from ground-based data, allows the identification of many…
Polaris: astrometric orbit, position, and proper motion
R. Wielen, H. Jahreiss, C. Dettbarn +2
We derive the astrometric orbit of the photo-center of the close pair alpha UMi AP (=alpha UMi Aa) of the Polaris multiple stellar system. The orbit is based on the spectroscopic o…
Indications on the binary nature of individual stars derived from a comparison of their HIPPARCOS proper motions with ground-based data I. Basic principles
R. Wielen, C. Dettbarn, H. Jahreiss +2
We present a method which provides some information on the possible binary nature on an appararently single star. The method compares the instantaneously measured HIPPARCOS proper…
The combination of ground-based astrometric compilation catalogues with the HIPPARCOS Catalogue I. Single-star mode
R. Wielen, H. Lenhardt, H. Schwan +1
The combination of ground-based astrometric compilation catalogues, such as the FK5 or the GC, with the results of the ESA Astrometric Satellite HIPPARCOS produces for many thousan…
The Sixth Catalogue of Fundamental Stars (FK6) and the Problem of Double Stars
R. Wielen, H. Schwan, C. Dettbarn +2
The Sixth Catalogue of Fundamental Stars (FK6) combines the ground-based astrometric data of the basic fundamental stars, obtained over more than two centuries and summarized in th…