TY  - JOUR
A1  - Pablo, Herbert
A1  - Richardson, Noel D.
A1  - Moffat, Anthony F. J.
A1  - Corcoran, Michael
A1  - Shenar, Tomer
A1  - Benvenuto, Omar
A1  - Fuller, Jim
A1  - Naze, Yael
A1  - Hoffman, Jennifer L.
A1  - Miroshnichenko, Anatoly
A1  - Apellaniz, Jesus Maiz
A1  - Evans, Nancy
A1  - Eversberg, Thomas
A1  - Gayley, Ken
A1  - Gull, Ted
A1  - Hamaguchi, Kenji
A1  - Hamann, Wolf-Rainer
A1  - Henrichs, Huib
A1  - Hole, Tabetha
A1  - Ignace, Richard
A1  - Iping, Rosina
A1  - Lauer, Jennifer
A1  - Leutenegger, Maurice
A1  - Lomax, Jamie
A1  - Nichols, Joy
A1  - Oskinova, Lida
A1  - Owocki, Stan
A1  - Pollock, Andy
A1  - Russell, Christopher M. P.
A1  - Waldron, Wayne
A1  - Buil, Christian
A1  - Garrel, Thierry
A1  - Graham, Keith
A1  - Heathcote, Bernard
A1  - Lemoult, Thierry
A1  - Li, Dong
A1  - Mauclaire, Benjamin
A1  - Potter, Mike
A1  - Ribeiro, Jose
A1  - Matthews, Jaymie
A1  - Cameron, Chris
A1  - Guenther, David
A1  - Kuschnig, Rainer
A1  - Rowe, Jason
A1  - Rucinski, Slavek
A1  - Sasselov, Dimitar
A1  - Weiss, Werner
T1  - A coordinated X-Ray and optical campaign of the nearest massive eclipsing binary, delta ORIONIS Aa. III. Analysis of optical photometric (most) and spectroscopic (ground based) variations
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report on both high-precision photometry from the Microvariability and Oscillations of Stars (MOST) space telescope and ground-based spectroscopy of the triple system delta Ori A, consisting of a binary O9.5II+early-B (Aa1 and Aa2) with P = 5.7 days, and a more distant tertiary (O9 IV P > 400 years). This data was collected in concert with X-ray spectroscopy from the Chandra X-ray Observatory. Thanks to continuous coverage for three weeks, the MOST light curve reveals clear eclipses between Aa1 and Aa2 for the first time in non-phased data. From the spectroscopy, we have a well-constrained radial velocity (RV) curve of Aa1. While we are unable to recover RV variations of the secondary star, we are able to constrain several fundamental parameters of this system and determine an approximate mass of the primary using apsidal motion. We also detected second order modulations at 12 separate frequencies with spacings indicative of tidally influenced oscillations. These spacings have never been seen in a massive binary, making this system one of only a handful of such binaries that show evidence for tidally induced pulsations.
KW  - binaries: close
KW  - binaries: eclipsing
KW  - stars: early-type
KW  - stars: individual (delta Ori A)
KW  - stars: mass-loss
KW  - stars: variables: general
Y1  - 2015
U6  - https://doi.org/10.1088/0004-637X/809/2/134
SN  - 0004-637X
SN  - 1538-4357
VL  - 809
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Ramiaramanantsoa, Tahina
A1  - Moffat, Anthony F. J.
A1  - Harmon, Robert
A1  - Ignace, R.
A1  - St-Louis, Nicole
A1  - Vanbeveren, Dany
A1  - Shenar, Tomer
A1  - Pablo, Herbert
A1  - Richardson, Noel D.
A1  - Howarth, Ian D.
A1  - Stevens, Ian R.
A1  - Piaulet, Caroline
A1  - St-Jean, Lucas
A1  - Eversberg, Thomas
A1  - Pigulski, Andrzej
A1  - Popowicz, Adam
A1  - Kuschnig, Rainer
A1  - Zoclonska, Elzbieta
A1  - Buysschaert, Bram
A1  - Handler, Gerald
A1  - Weiss, Werner W.
A1  - Wade, Gregg A.
A1  - Rucinski, Slavek M.
A1  - Zwintz, Konstanze
A1  - Luckas, Paul
A1  - Heathcote, Bernard
A1  - Cacella, Paulo
A1  - Powles, Jonathan
A1  - Locke, Malcolm
A1  - Bohlsen, Terry
A1  - Chené, André-Nicolas
A1  - Miszalski, Brent
A1  - Waldron, Wayne L.
A1  - Kotze, Marissa M.
A1  - Kotze, Enrico J.
A1  - Böhm, Torsten
T1  - BRITE-Constellation high-precision time-dependent photometry of the early O-type supergiant zeta Puppis unveils the photospheric drivers of its small- and large-scale wind structures
JF  - Monthly notices of the Royal Astronomical Society
N2  - From 5.5 months of dual-band optical photometric monitoring at the 1 mmag level, BRITE-Constellation has revealed two simultaneous types of variability in the O4I(n)fp star ζ Puppis: one single periodic non-sinusoidal component superimposed on a stochastic component. The monoperiodic component is the 1.78-d signal previously detected by Coriolis/Solar Mass Ejection Imager, but this time along with a prominent first harmonic. The shape of this signal changes over time, a behaviour that is incompatible with stellar oscillations but consistent with rotational modulation arising from evolving bright surface inhomogeneities. By means of a constrained non-linear light-curve inversion algorithm, we mapped the locations of the bright surface spots and traced their evolution. Our simultaneous ground-based multisite spectroscopic monitoring of the star unveiled cyclical modulation of its He ii λ4686 wind emission line with the 1.78-d rotation period, showing signatures of corotating interaction regions that turn out to be driven by the bright photospheric spots observed by BRITE. Traces of wind clumps are also observed in the He ii λ4686 line and are correlated with the amplitudes of the stochastic component of the light variations probed by BRITE at the photosphere, suggesting that the BRITE observations additionally unveiled the photospheric drivers of wind clumps in ζ Pup and that the clumping phenomenon starts at the very base of the wind. The origins of both the bright surface inhomogeneities and the stochastic light variations remain unknown, but a subsurface convective zone might play an important role in the generation of these two types of photospheric variability.
KW  - techniques: photometric
KW  - techniques: spectroscopic
KW  - stars: massive
KW  - stars: rotation
KW  - starspots
KW  - supergiants
KW  - stars: winds, outflows
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx2671
SN  - 0035-8711
SN  - 1365-2966
VL  - 473
IS  - 4
SP  - 5532
EP  - 5569
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  -