Journal Article

Evidence for the nearby F4V star λ Ara as a binary system

K. Fuhrmann, R. Chini, V. H. Hoffmeister and O. Stahl

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 415, issue 2, pages 1240-1243
Published in print August 2011 | ISSN: 0035-8711
Published online July 2011 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2011.18764.x
Evidence for the nearby F4V star λ Ara as a binary system

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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.

Keywords: binaries: spectroscopic; stars: fundamental parameters; stars: individual: λ Ara; stars: solar-type

Journal Article.  2205 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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