Search Publications
A Strategy for Identifying the Grid Stars for the Space Interferometry Mission
Quirrenbach, Andreas; Röser, Siegfried; Schilbach, Elena +2 more
We present a strategy to identify several thousand stars that are astrometrically stable at the microarcsecond level for use in the Space Interferometry Mission (SIM) astrometric grid. The requirements on the grid stars make this a rather challenging task. Taking a variety of considerations into account, we argue for K giants as the best type of s…
A Large Spectral Class Dependence of the Wilson-Bappu Effect among Luminous Stars
Parsons, Sidney B.
The striking correlation between Ca II K-line emission width and absolute visual magnitude has not previously been well calibrated for stars more luminous than giants. From a sample of binary systems fit to isochrones, we find deviations of more than 2 mag, correlated with spectral class, between these binarity Mv values and the Wilson-…