10 papers
The evolution of the Milky Way monitored in the solar neighbourhood
B. Fuchs, C. Dettbarn, H. Jahreiss +1
In this review we concentrate on the dynamical evolution of the Milky Way as monitored in the solar neighbourhood. The relevant data sets are presented and discussed in detail. In…
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…
The nearby M-dwarf system Gliese 866 revisited
Jens Woitas, Christoph Leinert, Hartmut Jahreiß +3
We present an improved orbit determination for the visual pair in the M-dwarf triple system Gliese 866 that is based on new speckle-interferometric and HST observations. The system…
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 contribution of brown dwarfs to the local mass budget of the Galaxy
B. Fuchs, H. Jahreiss, C. Flynn
Based on the recent discoveries of free floating brown dwarfs we derive estimates of the local mass density of this population of objects. Mass density estimates from various surve…