May 16, 2024

Magnetic Destiny: How a Wolf-Rayet Star Might Morph Into a Magnetar

This artists impression shows HD 45166, a massive star recently discovered to have a powerful magnetic field of 43,000 gauss, the strongest magnetic field ever discovered in a huge star. Extreme winds of particles blowing away from the star are trapped by this magnetic field, enshrouding the star in a gaseous shell as highlighted here.
Magnetar Origins Explored
New findings fixated observations and outstanding advancement designs of a hot, helium-rich Wolf-Rayet star recommend that it is set to produce a magnetar when it undergoes a supernova explosion. These findings provide a deeper understanding of the formation process of magnetars, which are considered the most magnetic entities in the Universe.
Understanding Magnetars and Neutron Stars
A magnetar is a specific kind of neutron star defined by a tremendously effective magnetic field. Normally, neutron stars originate from supernovae occasions where the core of a massive star collapses. Nevertheless, the origins of magnetars stay unclear.
One theory proposes that throughout a supernova explosion, the amplification of an electromagnetic field within the massive core of the progenitor star could result in the development of a magnetar. Such powerful magnetic fields have actually not been previously found in evolved stars that have the possible to turn into neutron stars post-explosion.

This artists impression highlights how, in a couple of million years, HD 45166 will blow up as a very bright, however not particularly energetic, supernova. During this surge, its core will contract, trapping and concentrating the stars already daunting magnetic field lines. Credit: NOIRLab/AURA/NSF/ P. Marenfeld/M. Zamani
The Discovery of HD 45166
Tomar Shenar and his research study group turned their attention to HD 45166, a double star including a primary series star and a hot Wolf-Rayet star companion. Wolf-Rayet stars are the exposed helium core of a massive star, having lost its outer hydrogen layers. Through using spectropolarimetric observations from the Canada-France-Hawaii Telescope and archival spectra from numerous other instruments, Shenar and his colleagues determined that the Wolf-Rayet element of HD 45166 has a mass equivalent to 2 solar masses and has a considerable electromagnetic field of 43 kilogauss.
This artists impression highlights the ultimate fate of HD 45166 after its core has collapsed, resulting in a neutron star with an electromagnetic field of around 100 trillion gauss– the most powerful type of magnet in the Universe. Credit: NOIRLab/AURA/NSF/ P. Marenfeld/M. Zamani
From Observations to Stellar Evolution Models
Depending on outstanding advancement designs and integrating the gotten information, the research study group inferred that this Wolf-Rayet component is destined to collapse into a neutron star. Their estimations recommend that the preservation of magnetic flux throughout this core collapse would magnify the magnetic fields strength, putting it within the series of what is observed for magnetars.
The authors conclude, “Our observations and stellar-evolution designs for that reason suggest that the Wolf-Rayet component could be an immediate progenitor of a magnetar.”
For more on this research:

This artists impression shows HD 45166, a massive star recently found to have an effective magnetic field of 43,000 gauss, the strongest magnetic field ever discovered in a massive star. Extreme winds of particles blowing away from the star are caught by this magnetic field, enshrouding the star in a gaseous shell as highlighted here. Typically, neutron stars originate from supernovae events where the core of an enormous star collapses. Tomar Shenar and his research study team turned their attention to HD 45166, a binary system consisting of a primary series star and a hot Wolf-Rayet star buddy. Wolf-Rayet stars are the exposed helium core of an enormous star, having actually lost its outer hydrogen layers.

Reference: “A massive helium star with a sufficiently strong electromagnetic field to form a magnetar” by Tomer Shenar, Gregg A. Wade, Pablo Marchant, Stefano Bagnulo, Julia Bodensteiner, Dominic M. Bowman, Avishai Gilkis, Norbert Langer, André Nicolas-Chené, Lidia Oskinova, Timothy Van Reeth, Hugues Sana, Nicole St-Louis, Alexandre Soares de Oliveira, Helge Todt and Silvia Toonen, 17 August 2023, Science.DOI: 10.1126/ science.ade3293.