Publications (35)
Analysis of eight magnetic chemically peculiar stars with rotational modulation
O. Kobzar, V. Khalack, D. Bohlender +9
Since the end of 2018, the Transiting Exoplanet Survey Satellite (TESS) has provided stellar photometry to the astronomical community. We have used TESS data to study rotational mo…
Vertical abundance stratification in the blue horizontal branch star HD135485
V. R. Khalack, F. LeBlanc, D. Bohlender +2
It is commonly believed that the observed overabundances of many chemical species relative to the expected cluster metallicity in blue horizontal branch (BHB) stars appear as a res…
Searching for Star-Planet interactions within the magnetosphere of HD 189733
R. Fares, J. -F. Donati, C. Moutou +7
HD 189733 is a K2 dwarf, orbited by a giant planet at 8.8 stellar radii. In order to study magnetospheric interactions between the star and the planet, we explore the large-scale m…
Search for vertical stratification of metals in atmospheres of blue horizontal-branch stars
V. R. Khalack, F. LeBlanc, B. B. Behr +2
The observed abundance peculiarities of many chemical species relative to the expected cluster metallicity in blue horizontal-branch (BHB) stars presumably appear as a result of at…
The magnetic field of the planet-hosting star Bootis
C. Catala, J. -F. Donati, E. Shkolnik +2
We have obtained high resolution spectropolarimetric data for the planet-hosting star Bootis, using the ESPaDOnS spectropolarimeter at CFHT. A weak but clear Stokes signat…
Study of slowly rotating CP stars observed with TESS
O. Kobzar, V. Khalack, D. Bohlender +10
Since the end of 2018, the Transiting Exoplanet Survey Satellite (TESS) provides high-quality space data on stellar photometry to the astronomical community. We present the results…
MOBSTER -- VI. The crucial influence of rotation on the radio magnetospheres of hot stars
M. E. Shultz, S. P. Owocki, A. ud-Doula +13
Numerous magnetic hot stars exhibit gyrosynchrotron radio emission. The source electrons were previously thought to be accelerated to relativistic velocities in the current sheet f…
Magnetic cycles of the planet-hosting star Tau Bootis: II. a second magnetic polarity reversal
R. Fares, J. -F. Donati, C. Moutou +7
In this paper, we present new spectropolarimetric observations of the planet-hosting star Tau Bootis, using ESPaDOnS and Narval spectropolarimeters at Canada-France-Hawaii Telescop…
gamma Peg: testing Vega-like magnetic fields in B stars
C. Neiner, D. Monin, B. Leroy +2
gam Peg is a bright B pulsator showing both p and g modes of beta Cep and SPB types. It has also been claimed to be a magnetic star by some authors while others do not detect a mag…
Magnetic cycles of the planet-hosting star tauBootis
J. F. Donati, C. Moutou, R. Fares +7
We have obtained new spectropolarimetric observations of the planet-hosting star tauBootis, using the ESPaDOnS and NARVAL spectropolarimeters at the Canada-France-Hawaii Telescope…
Discovery of magnetic fields in the very young, massive stars W601 (NGC 6611) and OI 201 (NGC 2244)
E. Alecian, G. A. Wade, C. Catala +8
Context: Recent spectropolarimetric observations of Herbig Ae/Be stars have yielded new arguments in favour of a fossil origin for the magnetic fields of intermediate mass stars. A…
The Magnetic Early B-type Stars IV: Breakout or Leakage? H emission as a diagnostic of plasma transport in centrifugal magnetospheres
M. E. Shultz, S. Owocki, Th. Rivinius +15
Rapidly rotating early-type stars with strong magnetic fields frequently show H emission originating in Centrifugal Magnetospheres (CMs), circumstellar structures in which cent…
Magnetic Doppler Imaging of He-strong star HD 184927
I. Yakunin, G. Wade, D. Bohlender +3
We have employed an extensive new timeseries of Stokes I and V spectra obtained with the ESPaDOnS spectropolarimeter at the 3.6-m Canada-France-Hawaii Telescope to investigate the…
The BinaMIcS project: understanding the origin of magnetic fields in massive stars through close binary systems
E. Alecian, C. Neiner, G. A. Wade +11
It is now well established that a fraction of the massive (M>8 Msun) star population hosts strong, organised magnetic fields, most likely of fossil origin. The details of the gener…
MOST Observations of sigma Ori E: Challenging the Centrifugal Breakout Narrative
R. H. D. Townsend, Th. Rivinius, J. F. Rowe +11
We present results from three weeks' photometric monitoring of the magnetic helium-strong star sigma Ori E using the MOST microsatellite. The star's light curve is dominated by twi…
Magnetic field, differential rotation and activity of the hot-Jupiter hosting star HD 179949
R. Fares, J. -F. Donati, C. Moutou +9
HD 179949 is an F8V star, orbited by a giant planet at ~8 R* every 3.092514 days. The system was reported to undergo episodes of stellar activity enhancement modulated by the orbit…
Relationship between low and high frequencies in Delta Scuti stars: Photometric Kepler and spectroscopic analyses of the rapid rotator KIC 8054146
M. Breger, L. Fossati, L. Balona +9
Two years of Kepler data of KIC 8054146 (delta Sct/gamma Dor hybrid) revealed 349 statistically significant frequencies between 0.54 and 191.36 c/d (6.3 microHz to 2.21 mHz). The 1…
HD 34736: An intensely magnetised double-lined spectroscopic binary with rapidly-rotating chemically peculiar B-type components
E. Semenko, O. Kochukhov, Z. Mikulášek +21
We report the results of a comprehensive study of the spectroscopic binary (SB2) system HD 34736 hosting two chemically peculiar (CP) late B-type stars. Using new and archival obse…
New Insights from Revisiting the Rotation Period of the Strongly Magnetic O Star, NGC 1624-2
S. Seadrow, V. Petit, G. A. Wade +5
NGC 1624-2 hosts the strongest surface magnetic field found on an O star thus far. When applied across several epochs of observations, the star's currently accepted rotation period…
An Inexpensive Liquid Crystal Spectropolarimeter for the Dominion Astrophysical Observatory Plaskett Telescope
D. Monin, D. Bohlender, T. Hardy +2
A new, inexpensive polarimetric unit has been constructed for the Dominion Astrophysical Observatory (DAO) 1.8-m Plaskett telescope. It is implemented as a plug-in module for the t…
An Analysis of the Rapidly Rotating Bp Star HD 133880
J. D. Bailey, J. Grunhut, M. Shultz +8
HD 133880 is a rapidly rotating Bp star and host to one of the strongest magnetic fields of any Bp star. A member of the Upper Centaurus Lupus association, it is a star with a well…
Regular frequency patterns in the young delta Scuti star HD 261711 observed by the CoRoT and MOST satellites
K. Zwintz, L. Fossati, D. B. Guenther +14
We concentrate on an asteroseismological study of HD 261711, a rather hot delta Scuti type pulsating member of the young open cluster NGC 2264 located at the blue border of the ins…
New Observations of the Strongly Magnetic O-star NGC 1624-2 Reveal Its Magnetic South Pole
S. Seadrow, V. Petit, D. Bohlender +6
NCG 1624-2 has the strongest detected magnetic field of all known main-sequence O-type stars. It was originally found that its magnetospheric emission lines followed a 5 mont…
The Magnetic Early B-type Stars III: A main sequence magnetic, rotational, and magnetospheric biography
M. E. Shultz, G. A. Wade, Th. Rivinius +10
Magnetic confinement of stellar winds leads to the formation of magnetospheres, which can be sculpted into Centrifugal Magnetospheres (CMs) by rotational support of the corotating…
Discovery of new magnetic early-B stars within the MiMeS HARPSpol survey
E. Alecian, O. Kochukhov, V. Petit +8
To understand the origin of the magnetic fields in massive stars as well as their impact on stellar internal structure, evolution, and circumstellar environment, within the MiMeS p…
Towards an understanding of the Of?p star HD 191612: optical spectroscopy
Ian D. Howarth, Nolan R. Walborn, Danny J. Lennon +17
We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is highly reprod…
The Magnetic Early B-type Stars I: Magnetometry and Rotation
M. E. Shultz, G. A. Wade, Th. Rivinius +7
The rotational and magnetic properties of many magnetic hot stars are poorly characterized, therefore the MiMeS and BinaMIcS collaborations have collected extensive high-dispersion…
A detailed spectropolarimetric analysis of the planet hosting star WASP-12
L. Fossati, S. Bagnulo, A. Elmasli +9
The knowledge of accurate stellar parameters is paramount in several fields of stellar astrophysics, particularly in the study of extrasolar planets, where often the star is the on…
Discovery of a magnetic field in the O9 sub-giant star HD 57682 by the MiMeS Collaboration
J. H. Grunhut, G. A. Wade, W. L. F. Marcolino +11
We report the detection of a strong, organised magnetic field in the O9IV star HD 57682, using spectropolarimetric observations obtained with ESPaDOnS at the 3.6-m Canada-France-Ha…
Vertical stratification of iron abundance in atmospheres of blue horizontal-branch stars
V. Khalack, F. LeBlanc, B. B. Behr +2
The observed slow rotation and abundance peculiarities of certain blue horizontal branch (BHB) stars suggests that atomic diffusion can be important in their stellar atmospheres an…
The surface magnetic field and chemical abundance distributions of the B2V helium-strong star HD184927
I. Yakunin, G. Wade, D. Bohlender +8
A new time series of high-resolution Stokes I and V spectra of the magnetic B2V star HD 184927 has been obtained in the context of the Magnetism in Massive Stars (MiMeS) Large Prog…
Discovery of the binary nature of the magnetospheric B-type star Oph A
M. E. Shultz, I. Berry, D. Bohlender +11
The nearby B-type star Oph A was recently identified as a rapidly rotating magnetic B-type star with variable radio and X-ray emission consistent with a magnetospheric origin.…
Absorbing gas around the WASP-12 planetary system
L. Fossati, T. R. Ayres, C. A. Haswell +3
Near-UV observations of the planet host star WASP-12 uncovered the apparent absence of the normally conspicuous core emission of the Mg2 h&k resonance lines. This anomaly could be…
A coordinated optical and X-ray spectroscopic campaign on HD179949: searching for planet-induced chromospheric and coronal activity
G. Scandariato, A. Maggio, A. F. Lanza +10
HD179949 is an F8V star, orbited by a close-in giant planet with a period of ~3 days. Previous studies suggested that the planet enhances the magnetic activity of the parent star,…
Discovery of a strong magnetic field in the rapidly rotating B2Vn star HR 7355
M. E. Oksala, G. A. Wade, W. L. F. Marcolino +5
We report the detection of a strong, organized magnetic field in the helium-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on the 3.6-m Ca…