The variability of the BRITE-est Wolf–Rayet binary, γ2 Velorum–I. Photometric and spectroscopic evidence for colliding winds

Noel D. Richardson, Christopher M. P. Russell, Lucas St-Jean, Anthony F. J. Moffat, Nicole St-Louis, Tomer Shenar, Herbert Pablo, Grant M. Hill, Tahina Ramiaramanantsoa, Michael Corcoran, Kenji Hamuguchi, Thomas Eversberg, Brent Miszalski, André-Nicolas Chené, Wayne Waldron, Enrico J. Kotze, Marissa M. Kotze, Paul Luckas, Paulo Cacella, Bernard Heathcote & 9 others Jonathan Powles, Terry Bohlsen, Malcolm Locke, Gerald Handler, Rainer Kuschnig, Andrzej Pigulski, Adam Popowicz, Gregg A. Wade, Werner W. Weiss

Research output: Contribution to journalArticle

Abstract

We report on the first multi-colour precision light curve of the bright Wolf–Rayet binary γ2 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 i λ5876 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 i 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 λ5696 of the system. These results represent the first in a series of investigations into the winds and properties of γ2 Velorum through multi-technique and multi-wavelength observational campaigns.
LanguageEnglish
Pages2715-2729
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume471
Issue number3
DOIs
StatePublished - 1 Nov 2017

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wolves
light curve
nanosatellites
orbits
constellations
line of sight
simulation
photometry
optical spectrum
cones
kinematics
shock
continuums
wavelength
color
high resolution
wavelengths

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Richardson, N. D., Russell, C. M. P., St-Jean, L., Moffat, A. F. J., St-Louis, N., Shenar, T., ... Weiss, W. W. (2017). The variability of the BRITE-est Wolf–Rayet binary, γ2 Velorum–I. Photometric and spectroscopic evidence for colliding winds. Monthly Notices of the Royal Astronomical Society, 471(3), 2715-2729. DOI: 10.1093/mnras/stx1731
Richardson, Noel D. ; Russell, Christopher M. P. ; St-Jean, Lucas ; Moffat, Anthony F. J. ; St-Louis, Nicole ; Shenar, Tomer ; Pablo, Herbert ; Hill, Grant M. ; Ramiaramanantsoa, Tahina ; Corcoran, Michael ; Hamuguchi, Kenji ; Eversberg, Thomas ; Miszalski, Brent ; Chené, André-Nicolas ; Waldron, Wayne ; Kotze, Enrico J. ; Kotze, Marissa M. ; Luckas, Paul ; Cacella, Paulo ; Heathcote, Bernard ; Powles, Jonathan ; Bohlsen, Terry ; Locke, Malcolm ; Handler, Gerald ; Kuschnig, Rainer ; Pigulski, Andrzej ; Popowicz, Adam ; Wade, Gregg A. ; Weiss, Werner W./ The variability of the BRITE-est Wolf–Rayet binary, γ2 Velorum–I. Photometric and spectroscopic evidence for colliding winds. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 471, No. 3. pp. 2715-2729
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abstract = "We report on the first multi-colour precision light curve of the bright Wolf–Rayet binary γ2 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 i λ5876 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 i 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 λ5696 of the system. These results represent the first in a series of investigations into the winds and properties of γ2 Velorum through multi-technique and multi-wavelength observational campaigns.",
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Richardson, ND, Russell, CMP, St-Jean, L, Moffat, AFJ, St-Louis, N, Shenar, T, Pablo, H, Hill, GM, Ramiaramanantsoa, T, Corcoran, M, Hamuguchi, K, Eversberg, T, Miszalski, B, Chené, A-N, Waldron, W, Kotze, EJ, Kotze, MM, Luckas, P, Cacella, P, Heathcote, B, Powles, J, Bohlsen, T, Locke, M, Handler, G, Kuschnig, R, Pigulski, A, Popowicz, A, Wade, GA & Weiss, WW 2017, 'The variability of the BRITE-est Wolf–Rayet binary, γ2 Velorum–I. Photometric and spectroscopic evidence for colliding winds' Monthly Notices of the Royal Astronomical Society, vol 471, no. 3, pp. 2715-2729. DOI: 10.1093/mnras/stx1731

The variability of the BRITE-est Wolf–Rayet binary, γ2 Velorum–I. Photometric and spectroscopic evidence for colliding winds. / Richardson, Noel D.; Russell, Christopher M. P.; St-Jean, Lucas; Moffat, Anthony F. J.; St-Louis, Nicole; Shenar, Tomer; Pablo, Herbert; Hill, Grant M.; Ramiaramanantsoa, Tahina; Corcoran, Michael; Hamuguchi, Kenji; Eversberg, Thomas; Miszalski, Brent; Chené, André-Nicolas; Waldron, Wayne; Kotze, Enrico J.; Kotze, Marissa M.; Luckas, Paul; Cacella, Paulo; Heathcote, Bernard; Powles, Jonathan; Bohlsen, Terry; Locke, Malcolm; Handler, Gerald; Kuschnig, Rainer; Pigulski, Andrzej; Popowicz, Adam; Wade, Gregg A.; Weiss, Werner W.

In: Monthly Notices of the Royal Astronomical Society, Vol. 471, No. 3, 01.11.2017, p. 2715-2729.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The variability of the BRITE-est Wolf–Rayet binary, γ2 Velorum–I. Photometric and spectroscopic evidence for colliding winds

AU - Richardson,Noel D.

AU - Russell,Christopher M. P.

AU - St-Jean,Lucas

AU - Moffat,Anthony F. J.

AU - St-Louis,Nicole

AU - Shenar,Tomer

AU - Pablo,Herbert

AU - Hill,Grant M.

AU - Ramiaramanantsoa,Tahina

AU - Corcoran,Michael

AU - Hamuguchi,Kenji

AU - Eversberg,Thomas

AU - Miszalski,Brent

AU - Chené,André-Nicolas

AU - Waldron,Wayne

AU - Kotze,Enrico J.

AU - Kotze,Marissa M.

AU - Luckas,Paul

AU - Cacella,Paulo

AU - Heathcote,Bernard

AU - Powles,Jonathan

AU - Bohlsen,Terry

AU - Locke,Malcolm

AU - Handler,Gerald

AU - Kuschnig,Rainer

AU - Pigulski,Andrzej

AU - Popowicz,Adam

AU - Wade,Gregg A.

AU - Weiss,Werner W.

PY - 2017/11/1

Y1 - 2017/11/1

N2 - We report on the first multi-colour precision light curve of the bright Wolf–Rayet binary γ2 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 i λ5876 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 i 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 λ5696 of the system. These results represent the first in a series of investigations into the winds and properties of γ2 Velorum through multi-technique and multi-wavelength observational campaigns.

AB - We report on the first multi-colour precision light curve of the bright Wolf–Rayet binary γ2 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 i λ5876 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 i 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 λ5696 of the system. These results represent the first in a series of investigations into the winds and properties of γ2 Velorum through multi-technique and multi-wavelength observational campaigns.

U2 - 10.1093/mnras/stx1731

DO - 10.1093/mnras/stx1731

M3 - Article

VL - 471

SP - 2715

EP - 2729

JO - Monthly Notices of the Royal Astronomical Society

T2 - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -

Richardson ND, Russell CMP, St-Jean L, Moffat AFJ, St-Louis N, Shenar T et al. The variability of the BRITE-est Wolf–Rayet binary, γ2 Velorum–I. Photometric and spectroscopic evidence for colliding winds. Monthly Notices of the Royal Astronomical Society. 2017 Nov 1;471(3):2715-2729. Available from, DOI: 10.1093/mnras/stx1731