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.

11 pages, 4 tables, 7 figures, accepted to MNRAS

References in corpus (12)

• Binary interaction dominates the evolution of massive stars
• Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
• The Galactic WN stars: Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation
• UBVJHK synthetic photometry of Galactic O stars
• Separated Fringe Packet Observations with the CHARA Array II: $\omega$ Andromeda, HD 178911, and ξ Cephei
• On the consistent treatment of the quasi-hydrostatic layers in hot star atmospheres
• Spatial distribution of Galactic Wolf-Rayet stars and implications for the global population
• The prototype colliding-wind pinwheel WR 104
• γ^2 Velorum: Orbital Solution and Fundamental Parameter Determination with SUSI
• Direct constraint on the distance of y2 Velorum from AMBER/VLTI observations
• The Expanding Fireball of Nova Delphini 2013
• Asymptotic Opening Angles for Colliding-Wind Bow Shocks: the Characteristic-Angle Approximation

Cited by in corpus (8)

• The impact of companions on stellar evolution
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars. I. The northern WC 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
• 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