The CHARA Array resolves the long-period Wolf-Rayet binaries WR 137 and WR 138

Abstract

We report on interferometric observations with the CHARA Array of two classical Wolf-Rayet stars in suspected binary systems, namely WR 137 and WR 138. In both cases, we resolve the component stars to be separated by a few milliarcseconds. The data were collected in the H-band, and provide a measure of the fractional flux for both stars in each system. We find that the WR star is the dominant H-band light source in both systems ($f_{\mathrm{WR},137}=0.59\pm 0.04$; $f_{\mathrm{WR},138}=0.67\pm 0.01$), which is confirmed through both comparisons with estimated fundamental parameters for WR stars and O dwarfs, as well as through spectral modeling of each system. Our spectral modeling also provides fundamental parameters for the stars and winds in these systems. The results on WR 138 provide evidence that it is a binary system which may have gone through a previous mass-transfer episode to create the WR star. The separation and position of the stars in the WR 137 system together with previous results from the IOTA interferometer provides evidence that the binary is seen nearly edge-on. The possible edge-on orbit of WR 137 aligns well with the dust production site imaged by the Hubble Space Telescope during a previous periastron passage, showing that the dust production may be concentrated in the orbital plane.

arXiv comment11 pages, 4 tables, 7 figures, accepted to MNRAS

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Cited by in corpus (13)

• The impact of companions on stellar evolution
• A Modern Search for Wolf-Rayet Stars in the Magellanic Clouds. IV. A Final Census
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars. I. The northern WC sequence
• The orbit and stellar masses of the archetype colliding-wind binary WR 140
• The Tarantula Massive Binary Monitoring V. R 144: a wind-eclipsing binary with a total mass > 140 Msun
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars: II. The northern WNE sequence
• The First Dynamical Mass Determination of a Nitrogen-rich Wolf-Rayet Star using a Combined Visual and Spectroscopic Orbit
• The variability of the BRITE-est Wolf-Rayet binary, ${\gamma }^2$ Velorum I. Photometric and spectroscopic evidence for colliding winds
• Constraints on the multiplicity of the most massive stars known: R136 a1, a2, a3, and c
• Investigating 39 Galactic Wolf-Rayet stars with VLTI/GRAVITY: Uncovering A Long Period Binary Desert
• An extensive spectroscopic time series of three Wolf-Rayet stars -- II. A search for wind asymmetries in the dust-forming WC7 binary WR137
• A Speckle-Imaging Search for Close and Very Faint Companions to the Nearest and Brightest Wolf-Rayet Stars
• Revisiting the orbital motion of WR 138