Highlighted Research
By A. Biswas, B. Das, J. Barron, G.A. Wade, and G. Holgado
The Astrophysical Journal, in press
HR 5907 (HD 142184) stands out among magnetic OB stars for its rapid rotation, exceptionally hard X-ray emission, and strong magnetic field. High-frequency (>5 GHz) radio emission from the star exhibits an approximately flat spectrum that can be attributed to gyrosynchrotron emission from a dense centrifugal magnetosphere. In a survey of radio emission from massive stars at sub-GHz frequencies, we noticed remarkable low-frequency radio emission from this star, characterized by high circular polarization and brightness temperature, which is inconsistent with the gyrosynchrotron model. We present a follow-up low-frequency radio study of this star with the upgraded Giant Metrewave Radio Telescope (uGMRT) in search of emission mechanisms that can go undiagnosed at higher frequencies. We detect variable radio emission characterized by varying degrees of circular polarization (15-45%) throughout the rotation cycle. The broad-band spectral fitting also suggests additional emission components at lower frequencies. We show that the observed emission is likely auroral emission via electron cyclotron maser emission (ECME), and identify this star as a Main-sequence Radio Pulse emitter (MRP). For MRPs, ECME is usually observed as short polarized enhancements near the magnetic nulls of the star. The detection of a high degree of circular polarization (>15%) at all times makes HR 5907 unique among MRPs. This is only the second MRP after Rho Oph C (detected polarization fraction: 0-60%) that exhibits persistent coherent radio emission attributed to the nearly aligned stellar magnetic and rotational axes.
Research
Dr. Wade investigates the structure, evolution, origin and impact of magnetic fields in stars. His research concentrates on intermediate and high mass stars, which are the evolutionary progenitors of most white dwarfs, neutron stars and stellar-mass black holes. He is the Principal Investigator (PI) of the Magnetism in Massive Stars (MiMeS) collaboration, co-PI of the Binarity and Magnetic Interactions in Stars (BinaMIcS) project, and past-Chair of the international BRITE Executive Science Team (BEST) for the BRITE-Constellation mission.
In the context of RMC’s Space Surveillance Research Laboratory (SSRL), Dr. Wade has also directed research related to the characterization of the structure, surface composition, and rotation of artificial satellites.
Dr. Wade was awarded RMC’s Cowan Prize for Excellence in Research in 2019. His current research is focused on exploring exotic pathways to magnetic field generation in massive stars, understanding magnetic field properties and implications at later evolutionary phases of intermediate-mass and massive stars, and understanding non-thermal X-ray and radio emission from magnetic hot stars.
Recent Publications
- “HD 34736: an intensely magnetised double-lined spectroscopic binary with rapidly rotating chemically peculiar B-type components”, Semenko, E., Kochukhov, O., Mikulášek, Z., Wade, G. A., Alecian, E., Bohlender, D., Das, B., Feliz, D. L., Janík, J., Kolář, J., Krtička, J., Kudryavtsev, D. O., Labadie-Bartz, J. M., Mkrtichian, D., Monin, D., Petit, V., Romanyuk, I. I., Shultz, M. E., Shulyak, D., Siverd, R. J., Tkachenko, A., Yakunin, I. A., Zejda, M., and the BinaMIcS collaboration (2024) Monthly Notices of the Royal Astronomical Society, 535, 2812-2836
- “First Observation of the Complete Rotation Period of the Ultraslowly Rotating Magnetic O Star HD 54879”, Erba, C., Folsom, C. P., David-Uraz, A., Wade, G. A., Seadrow, S., Bellotti, S., Fossati, L., Petit, V., and Shultz, M. E. (2024) The Astrophysical Journal, 977, 84
- “XMM-Newton Perspective of the Unique Magnetic Binary Epsilon Lupi”, Biswas, Ayan, Wade, Gregg A., Chandra, Poonam, Petit, Veronique, Das, Barnali, and Shultz, Matthew E. (2024) The Astrophysical Journal, 974, 182
- “NIRPS near-infrared spectrograph: AITV phase at ESO3.6m/La Silla”, Malo, Lison, Baron, Frédérique, Poulin-Girard, Anne-Sophie, Vallée, et al. Including Wade, Gregg A. (2024) Ground-based and Airborne Instrumentation for Astronomy X, 13096, 1309646
- “ANDES, the high resolution spectrograph for the ELT: science goals, project overview, and future developments”, Marconi, A., Abreu, M., Adibekyan, V., Alberti, V., et al. Including Wade, G.A. (2024) Ground-based and Airborne Instrumentation for Astronomy X, 13096, 1309613
- “NIRPS first light and early science: breaking the 1 m/s RV precision barrier at infrared wavelengths”, Artigau, Étienne, Bouchy, François, Doyon, René, et al. Including Wade, Gregg A. (2024) Ground-based and Airborne Instrumentation for Astronomy X, 13096, 130960C
- “Magnetic Fields of Massive Stars, on and after the Main Sequence”, Wade, Gregg (2024) Bulletin de la Societe Royale des Sciences de Liege, 93, 514-527
- “A magnetic massive star has experienced a stellar merger”, Frost, A. J., Sana, H., Mahy, L., Wade, G., Barron, J., Le Bouquin, J. -B., Mérand, A., Schneider, F. R. N., Shenar, T., Barbá, R. H., Bowman, D. M., Fabry, M., Farhang, A., Marchant, P., Morrell, N. I., and Smoker, J. V. (2024) Science, 384, 214-217
- “The discovery space of ELT-ANDES. Stars and stellar populations”, Roederer, Ian U., Alvarado-Gómez, Julián D., Allende Prieto, Carlos, et al. Including Wade, Gregg A.(2024) Experimental Astronomy, 57, 17
- “Catalogue of BRITE-Constellation targets. I. Fields 1 to 14 (November 2013-April 2016)”, Zwintz, K., Pigulski, A., Kuschnig, R., Wade, G. A., Doherty, G., Earl, M., Lovekin, C., Müllner, M., Piché-Perrier, S., Steindl, T., Beck, P. G., Bicz, K., Bowman, D. M., Handler, G., Pablo, B., Popowicz, A., Różański, T., Mikołajczyk, P., Baade, D., Koudelka, O., Moffat, A. F. J., Neiner, C., Orleański, P., Smolec, R., Louis, N. St., Weiss, W. W., Wenger, M., and Zocłońska, E. (2024) Astronomy and Astrophysics, 683, A49
- “The large-scale magnetic field of the M dwarf double-line spectroscopic binary FK Aqr”, Tsvetkova, S., Morin, J., Folsom, C. P., Le Bouquin, J. -B., Alecian, E., Bellotti, S., Hussain, G., Kochukhov, O., Marsden, S. C., Neiner, C., Petit, P., Wade, G. A., and BinaMIcS Collaboration (2024) Astronomy and Astrophysics, 682, A77
A complete list of publications is available at: The SAO/NASA Astrophysics Data System .
In the News
- Scientists unlock mysteries of magnetars, the most magnetic objects in the universe
- New type of star gives clue to mysterious origin of magnetars
- A Companion for Regulus
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NGC 1624-2 has a complex magnetospheric structure, observations reveal
- BRITE-Constellation helps to reveal the power of shock waves in a nova explosion
- BRITE-Constellation: Tiny Satellites for Big Science (video)
- A new star in the sky
- Spots on supergiant star drive spirals in stellar wind
- Iota Orionis: pulsating beacon of a constellation
- Magnetic stars responsible for LIGO’s “heavy” stellar-mass black holes?
- Measuring stellar magnetic fields with HARPSpol in the Southern Hemisphere
- X ray emission (and absorption) from the giant magnetosphere of the star NGC 1624-2
- Discovery of a magnetic field in epsilon Lupi: the first double-magnetic massive binary system
- Monitoring stellar magnetospheres
- Discovery of the most strongly magnetized O-type star
- Spots spotted on the bright star Vega
Graduate students
Current students
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Iris Bermejo Lozano (PhD, Charles)
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Lindsay Holmes (PhD, RMC)
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James Barron (PhD, Queen's)
- Ayan Biswas (PhD, Queen’s)
Past students
- Angelo Hollett (MSc, Queen’s)
- Erik Stacey (MSc, RMC)
- James Barron (MSc, Queen's)
- Melissa Munoz (PhD, Queen’s) - withdrew
- Giuseppe Ramacieri (MSc, RMC) - Canadian Forces
- James Sikora (PhD, Queen's) - Postdoctoral Fellow, Sherbrooke university
- Zsolt Keszthelyi (PhD, Queen's) - Postdoctoral Fellow, University of Amsterdam
- Michael Earl (PhD, RMC) - Assistant Professor, RMC
- Jason Shaw (MSc, RMC) (with Dr. Donald Bédard) - Canadian Forces
- Matthew Shultz (PhD, Queen's) - Annie Jump Cannon Postdoctoral Fellow, University of Delaware
- Carl Clancy (MSc, RMC) (with Dr. Donald Bédard) - Flt Lt, Australian Air Force
- Alexandre David-Uraz (PhD, Queen's) - NSERC Postdoctoral fellow, University of Delaware
- Alex Willison (MSc) (with Dr. Donald Bédard)
- James Silvester (PhD)
- Andrew Jolley (MSc) - Australian Air Force
- Donald Bédard (PhD) - Canadian Forces
- Michael Earl (MSc)
- Jason Grunhut (PhD) - Data Scientist, Telus Canada
- Matthew Shultz (MSc)
- M. Oksala (PhD) (with Prof. Stanley Owocki) - Assistant Professor, California Lutheran University
- Véronique Petit (PhD) (with Prof. Laurent Drissen) - Assistant Professor, University of Delaware
- Katherine Likuski (MSc) - Canadian Forces
- Jason Grunhut (MSc)
- Mouhamadou Thiam (MSc) (with Prof. Francis LeBlanc) - PhD Candidate, Moncton University
- Jennifer Power (MSc) - Observing assistant, LBTO, USA
- Colin Folsom (MSc) - Postdoc, Toulouse, France
- James Silvester (MSc)
- Dominic Drouin (MSc) - Canadian Forces
- Noémie Johnson (MSc) - MD graduate, Canadian Forces physician
Comments
Comments or suggestions are welcomed at: bryce.bennett@rmc-cmr.ca