Evidence of a third star orbiting the eclipsing binary delta Librae

Authors
Citation
Tf. Worek, Evidence of a third star orbiting the eclipsing binary delta Librae, PUB AST S P, 113(786), 2001, pp. 964-969
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
0004-6280 → ACNP
Volume
113
Issue
786
Year of publication
2001
Pages
964 - 969
Database
ISI
SICI code
0004-6280(200108)113:786<964:EOATSO>2.0.ZU;2-3
Abstract
Radial velocity observations obtained at the Kitt Peak National Observatory in 1981, 1983, 1984, and 1991 confirm the suggestion made by McLaughlin si x decades ago that the bright Algol-type binary delta Librae has a long-per iod companion. An analysis of this eclipsing system's barycentric velocity for these four epochs and four earlier ones where published observations we re available yield these spectroscopic elements for its center of mass: P=2 .762 +/-0.001 yr, K = 5.46 +/-0.15 km s(-1), e = 0.28 +/-0.05, omega = 198 degrees +/-7 degrees, and t = 1983.24 +/-0.04. From these results, it can b e inferred that the the third star's mass and spectral type are 0.95 +/-0.0 4 M-circle dot and G9 and the entire delta Lib system is even more similar to the archetypal eclipsing binary beta Persei (Algol) than was previously recognized. The spectroscopic orbital elements for the B9.5 V primary star in the eclipsing system are also update.