Volume 600, April 2017
|Number of page(s)||15|
|Section||Stellar structure and evolution|
|Published online||24 March 2017|
Physical properties of seven binary and higher-order multiple OB systems⋆
1 Astronomical Institute of the Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, 180 00 Praha 8, Czech Republic
2 Astronomisches Institut, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum, Germany
3 Instituto de Astronomía, Universidad Católica del Norte, Avenida Angamos 0610, Casilla 1280, Antofagasta, Chile
4 Dr. Karl Remeis-Observatory & ECAP, Astronomical Institute, Friedrich-Alexander-University Erlangen-Nuremberg, Sternwartstr. 7, 96049 Bamberg, Germany
5 Department of Physics, High Point University, One University Way, High Point, NC 27268, USA
6 Royal Observatory of Belgium, Avenue circulaire 3, 1180 Brussels, Belgium
7 Astronomical Institute, Academy of Sciences of the Czech Republic, 251 65 Ondřejov, Czech Republic
Received: 4 May 2016
Accepted: 14 December 2016
Analyses of multi-epoch, high-resolution (R ~ 50 000) optical spectra of seven early-type systems provided various important new insights with respect to their multiplicity. First determinations of orbital periods were made for HD 92206 C (2022), HD 112244 (27665), HD 164438 (1025), HD 123056 A (~1314 d) and HD 123056 B (<2 d); the orbital period of HD 318015 could be improved (23445975). Concerning multiplicity, a third component was discovered for HD 92206 C by means of He i line profiles. For HD 93146 A, which was hitherto assumed to be SB1, lines of a secondary component could be discerned. HD 123056 turns out to be a multiple system consisting of a high-mass component A (≈O8.5) displaying a broad He ii 5411 Å feature with variable radial velocity, and of an inner pair B (≈B0) with double He i lines. The binary HD 164816 was revisited and some of its system parameters were improved. In particular, we determined its systemic velocity to be −7 km s-1, which coincides with the radial velocity of the cluster NGC 6530. This fact, together with its distance, suggests the cluster membership of HD 164816. The OB system HD 318015 (V1082 Sco) belongs to the rare class of eclipsing binaries with a supergiant primary (B0.5/0.7). Our combined orbital and light-curve analysis suggests that the secondary resembles an O9.5 III star. Our results for a limited sample corroborate the findings that many O stars are actually massive multiple systems.
Key words: binaries: spectroscopic / stars: massive / stars: fundamental parameters / stars: general
Based on spectra from observations made with ESO telescopes at La Silla and Paranal Observatories under programs 065.1-0526(A), 073.C-0337(A), 074.D-0300(A), 075.D-0103(A), 077.D-0705(A), 077.B-0348(A), 079.D-0564(A), 081.D-2008(A), 083.D-0589(A), 085.D-0262(A), 086.D-0997(A), 087.C-0012(A), 087.D-0946(A), 089.C-0415(A), 089.D-0097(B), 089.D-0975(A), 090.C-0280(A), 091.D-0145(A), 095.A-9032(A), and 178.D-0361(E), program TYCHO P2, on the BESO spectra and spectra from CTIO, and on the Hipparcos Hp and ASAS3 V photometry.
© ESO, 2017
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