Overview of Multiple-Aperture Interferometry Binary Star Results from the Southern Hemisphere
Abstract
The first multiple-aperture interferometric study of a binary system, in which the power of combining interferometric and spectroscopic data was demonstrated, was made from the Southern Hemisphere. The observations of Alpha Virginis with the Narrabri Stellar Intensity Interferometer (NSII), made in 1966 and 1970, were combined with spectroscopic and photometric data to yield the mass, radius and luminosity of the primary component as well as an accurate distance to the system. The NSII also revealed a number of stars, previously thought to be single, to be binary systems but the instrument lacked the capability to determine their orbits. Several of these systems have subsequently been shown to be spectroscopic binaries and, more recently, the Sydney University Stellar Interferometer (SUSI) has been used to determine interferometric orbits for some of them. In combination with spectroscopic data the SUSI results have led to accurate values for the masses of early type stars and accurate distances to the systems. Gamma 2 Velorum, the brightest Wolf-Rayet binary system, has recently been observed with SUSI to determine its orbit and, in combination with spectroscopic data, to determine the masses for the O-type giant and Wolf-Rayet (WC8) component stars and the distance to the system. The status and future plans for the SUSI programme will be described. The other Southern Hemisphere multiple-aperture optical/IR interferometric instrument is the European Southern Observatory's Very Large Telescope Interferometer (VLTI). To data few observations of binary systems have been made with the VLTI but the status and plans for the future will be outlined.
- Publication:
-
Binary Stars as Critical Tools & Tests in Contemporary Astrophysics
- Pub Date:
- August 2007
- DOI:
- 10.1017/S174392130700378X
- Bibcode:
- 2007IAUS..240...45D