Analysis of delta Librae including Hipparcos astrometry
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol.370, no.4, pp.1935-1945, 2006 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 370 Issue: 4
- Publication Date: 2006
- Doi Number: 10.1111/j.1365-2966.2006.10619.x
- Journal Name: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.1935-1945
- Keywords: binaries : close, stars : individual : delta Lib, ECLIPSING BINARIES, ALGOL SYSTEM, STARS, PHOTOMETRY, EVOLUTION, VELOCITY, CURVES
- Open Archive Collection: AVESIS Open Access Collection
- Akdeniz University Affiliated: No
Abstract
New spectroscopy of the classical Algol system delta Lib, combined with high-quality optical and infrared photometry, provides the basis for a good understanding of the close binary system's main parameters. Detailed analysis of the photometry reveals the significant role of a third light source, pointing to the existence of a companion to the eclipsing system of mass similar to 1 M-circle dot.
We review the methodology of applying high-accuracy positional information, available from the Hipparcos Intermediate Astrometric Data archive, to stars that may have such companions. Analysis of the astrometry of delta Lib also points to a third star similar to the one already identified by Worek from radial-velocity data, although with slightly revised parameters. O-C data do not contradict this, but their general precision (while confirming the close pair's Algol status) fails to allow a decision on the third orbit parameters: Worek's or revised ones. Taking the photometry, spectroscopy and astrometry together, however, the existence of a third star of comparable mass to the Sun, as a relatively close companion to the eclipsing binary (similar to 4 au), is confirmed.