The binary star HD 45166 includes a peculiar Wolf-Rayet star, which is unusual even by the standards of this group of extreme stars. It dramatically spews matter into the surrounding space and at the same time is gripped by a magnetic field with an induction of 43 thousand gauss, which makes it a magnetic record holder among massive stars in the known universe. When it explodes as a supernova, it will probably end up as a brutally magnetic neutron star, or magnetar.
Extreme pair HD 45166. Credit: NOIRLab/AURA/NSF/P. Marenfeld/M.
We have known the star HD 45166 for over 100 years. It is a Wolf-Rayet star, or a wild star monster in the final phase of its very short life, which in this case we observe at a distance of about 3 thousand light years in the constellation of the Unicorn. It contains a large amount of helium and has its own stellar companion. All of Wolf-Rayet’s stars are exceptional and, frankly, pretty scary too. Like a big star being possessed by a demon.
Tom Shenar. Credit: T. Shenar.
However, HD 45166 is exceptional even among Wolf-Rayet stars. It ejects even more matter than is usual for these wild giants and does it in a different way. Experts have long puzzled over what this star actually is. A team of astronomers led by Tomer Shenar from the Netherlands’ University of Amsterdam has come up with a remarkable answer.
Researchers found that this special star monster has an amazingly strong magnetic field, the magnetic induction of which reaches 43 thousand gauss.
Magnetic monster. Credit: ESO/L. Calçada
Regarding the Sun, for example, there is a magnetic field with an induction of around 1,500 gauss in the sunspot region. The star HD 45166 has just officially become the most magnetic of all known massive stars in the universe. According to Shenar, this is a new category of stellar objects that have been hiding from our eyes.
Observations by Shenar’s team also showed that the Wolf-Rayet star in question is lighter than originally thought. Weighs like 2 Suns. With its companion, which is a blue-white hot and bright star of spectral class B, it orbits once every 8,200 Earth days. Scientists are not clear how this particular Wolf-Rayet star became so extremely magnetic. They believe that this could happen, for example, after the collision and merger of two smaller stars. In such a case, the question is whether magnetars can be created only by this very exceptional scenario or by other paths as well.
What’s next for the exceptional Wolf-Rayet star? It should explode as a supernova within a few million years. Its core collapses in on itself and concentrates the existing magnetic field of this star into a confined space. The result should be an absolutely stunning magnetic field with an induction of around 100 trillion gauss. In other words, in the case of the star HD 45166, we seem to have encountered the first known magnetar precursor.
Video: Artist’s animation of HD 45166, the most magnetic massive star ever found
Literature
2023-08-20 07:42:02
#magnetic #star #universe #dies #magnetar
