The Massive Wolf-Rayet Binary SMC WR7

Abstract

We present a study of optical spectra of the Wolf--Rayet star AzV 336a (= SMC WR7) in the Small Magellanic Cloud. Our study is based on data obtained at several Observatories between 1988 and 2001. We find SMC WR7 to be a double lined WN+O6 spectroscopic binary with an orbital period of 19.56 days. The radial velocities of the He absorption lines of the O6 component and the strong He{\sc ii} emission at $\lambda$4686Åof the WN component describe antiphased orbital motions. However, they show a small phase shift of $\sim$ 1 day. We discuss possible explanations for this phase shift. The amplitude of the radial velocity variations of He {\sc ii} emission is twice that of the absorption lines. The binary components have fairly high minimum masses, $\sim$ 18 $\modot$ and 34 $\modot$ for the WN and O6 components, respectively.

Accepted by MNRAS

References in corpus (2)

• A Search for Wolf-Rayet Stars in the Small Magellanic Cloud
• Orbits of Four Very Massive Binaries in the R136 Cluster

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• WR bubbles and HeII emission
• Exploring the borderline between stable mass transfer and mergers in close binary evolution
• Constraints on the Binarity of the WN3/O3 Class of Wolf-Rayet Stars
• Empirical correlation between masses of black holes and Wolf-Rayet stars derived from their mass distributions in spectroscopic binaries