Evidence for the nearby F4V star λ Ara as a binary system
Abstract
We report on the spectroscopic evidence for the nearby, bright and supposedly single F4V star λ Ara as a binary system. The basic observational tracer is a discrepancy with the Hipparcos-based astrometric surface gravity as opposed to the spectroscopically derived value from the pressure-dependent Mg Ib triplet lines. We demonstrate how this discrepancy can be met with an equal-mass secondary hidden in the light of the star’s considerable projected rotational velocity vsin i = 15.5 ± 1.0 km s-1 and we expect this scenario to be testable with high-angular resolution direct imaging observations. A major consequence should be the discovery of other nearby binary systems with a similar architecture.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- August 2011
- DOI:
- 10.1111/j.1365-2966.2011.18764.x
- Bibcode:
- 2011MNRAS.415.1240F
- Keywords:
-
- binaries: spectroscopic;
- stars: fundamental parameters;
- stars: individual: λ Ara;
- stars: solar-type