TY - JOUR A1 - Richardson, Noel D. A1 - Shenar, Tomer A1 - Roy-Loubier, Olivier A1 - Schaefer, Gail A1 - Moffat, Anthony F. J. A1 - St-Louis, Nicole A1 - Gies, Douglas R. A1 - Farrington, Chris A1 - Hill, Grant M. A1 - Williams, Peredur M. A1 - Gordon, Kathryn A1 - Pablo, Herbert A1 - Ramiaramanantsoa, Tahina T1 - The CHARA Array resolves the long-period Wolf-Rayet binaries WR 137 and WR 138 JF - Monthly notices of the Royal Astronomical Society N2 - We report on interferometric observations with the CHARAArray of two classical Wolf-Rayet (WR) 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 (fWR, 137 = 0.59 +/- 0.04; fWR, 138 = 0.67 +/- 0.01), which is confirmed through both comparisons with estimated fundamental parameters for WR stars and O dwarfs, as well as through spectral modelling of each system. Our spectral modelling 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 edgeon. 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. KW - binaries: visual KW - stars: individual: WR 137 KW - stars: individual: WR 138 KW - stars: mass-loss KW - stars: winds, outflows KW - stars: Wolf-Rayet Y1 - 2016 U6 - https://doi.org/10.1093/mnras/stw1585 SN - 0035-8711 SN - 1365-2966 VL - 461 SP - 4115 EP - 4124 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Munoz, Melissa A1 - Moffat, Anthony F. J. A1 - Hill, Grant M. A1 - Shenar, Tomer A1 - Richardson, Noel D. A1 - Pablo, Herbert A1 - St-Louis, Nicole A1 - Ramiaramanantsoa, Tahina T1 - WR 148: identifying the companion of an extreme runaway massive binary JF - Monthly notices of the Royal Astronomical Society N2 - WR 148 (HD 197406) is an extreme runaway system considered to be a potential candidate for a short-period (4.3173 d) rare WR + compact object binary. Provided with new high-resolution, high signal-to-noise spectra from the Keck observatory, we determine the orbital parameters for both the primary WR and the secondary, yielding respective projected orbital velocity amplitudes of 88.1 ± 3.8 km s−1 and 79.2 ± 3.1 km s−1 and implying a mass ratio of 1.1 ± 0.1. We then apply the shift-and-add technique to disentangle the spectra and obtain spectra compatible with a WN7ha and an O4-6 star. Considering an orbital inclination of ∼67°, derived from previous polarimetry observations, the system's total mass would be a mere 2–3M⊙⁠, an unprecedented result for a putative massive binary system. However, a system comprising a 37M⊙ secondary (typical mass of an O5V star) and a 33M⊙ primary (given the mass ratio) would infer an inclination of ∼18°. We therefore reconsider the previous methods of deriving the orbital inclination based on time-dependent polarimetry and photometry. While the polarimetric results are inconclusive requiring better data, the photometric results favour low inclinations. Finally, we compute WR 148’s space velocity and retrace the runaway's trajectory back to the Galactic plane (GP). With an ejection velocity of 198 ± 27 km s−1 and a travel time of 4.7 ± 0.8 Myr to reach its current location, WR 148 was most likely ejected via dynamical interactions in a young cluster. KW - binaries: spectroscopic KW - stars: individual: WR 148 KW - stars: kinematics and dynamics KW - stars: mass-loss KW - stars: winds, outflows KW - stars: Wolf-Rayet Y1 - 2017 U6 - https://doi.org/10.1093/mnras/stw2283 SN - 0035-8711 SN - 1365-2966 VL - 467 SP - 3105 EP - 3121 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Richardson, Noel D. A1 - Russell, Christopher M. P. A1 - St-Jean, Lucas A1 - Moffat, Anthony F. J. A1 - St-Louis, Nicole A1 - Shenar, Tomer A1 - Pablo, Herbert A1 - Hill, Grant M. A1 - Ramiaramanantsoa, Tahina A1 - Corcoran, Michael A1 - Hamuguchi, Kenji A1 - Eversberg, Thomas A1 - Miszalski, Brent A1 - Chene, Andre-Nicolas A1 - Waldron, Wayne A1 - Kotze, Enrico J. A1 - Kotze, Marissa M. A1 - Luckas, Paul A1 - Cacella, Paulo A1 - Heathcote, Bernard A1 - Powles, Jonathan A1 - Bohlsen, Terry A1 - Locke, Malcolm A1 - Handler, Gerald A1 - Kuschnig, Rainer A1 - Pigulski, Andrzej A1 - Popowicz, Adam A1 - Wade, Gregg A. A1 - Weiss, Werner W. T1 - The variability of the BRITE-est Wolf-Rayet binary, gamma(2) Velorum-I. Photometric and spectroscopic evidence for colliding winds JF - Monthly notices of the Royal Astronomical Society N2 - We report on the first multi-colour precision light curve of the bright Wolf-Rayet binary gamma(2) Velorum, obtained over six months with the nanosatellites in the BRITE-Constellation fleet. In parallel, we obtained 488 high-resolution optical spectra of the system. In this first report on the data sets, we revise the spectroscopic orbit and report on the bulk properties of the colliding winds. We find a dependence of both the light curve and excess emission properties that scales with the inverse of the binary separation. When analysing the spectroscopic properties in combination with the photometry, we find that the phase dependence is caused only by excess emission in the lines, and not from a changing continuum. We also detect a narrow, high-velocity absorption component from the He perpendicular to lambda 5876 transition, which appears twice in the orbit. We calculate smoothed-particle hydrodynamical simulations of the colliding winds and can accurately associate the absorption from He perpendicular to to the leading and trailing arms of the wind shock cone passing tangentially through our line of sight. The simulations also explain the general strength and kinematics of the emission excess observed in wind lines such as C III lambda 5696 of the system. These results represent the first in a series of investigations into the winds and properties of gamma(2) Velorum through multi-technique and multi-wavelength observational campaigns. KW - stars: early type KW - stars: individual: gamma(2) Vel KW - stars: mass loss KW - stars: winds KW - outflows KW - stars: Wolf-Rayet Y1 - 2017 U6 - https://doi.org/10.1093/mnras/stx1731 SN - 0035-8711 SN - 1365-2966 VL - 471 SP - 2715 EP - 2729 PB - Oxford Univ. Press CY - Oxford ER -