Multi-Facility Study of the Algol-Type Binary δ Librae

Various branches of observational information, and related physical problems concerning the bright, relatively close, Algol binary δ Lib are discussed. Times of minimum light confirm the classical Algol status, which, combined with the optical and IR photometry of Lazaro et al. (2002), provide the basis for a good understanding of the system’s basic parameters. New spectroscopy from the Coudé spectrograph of the Rozhen Observatory (Bulgaria) allows further information on the model and the mass transfer process. Very high resolution radio observations would also have much to reveal about astrophysics of the semi-detached configuration, not only directly, by informing about the outermost envelopes of the components, but indirectly through high accuracy positional information. We show how this may be related to careful period and astrometric studies. δ Lib thus provides a rich source of information on the astrophysics of the Algol configuration.