Far far away, in a constellation called Monoceros, 3000 light years away from us, lives an unusual star known as HD 45166 - preparing to become the most magnetic powerhouse to exist in the known Universe.
Magnetars are a type of neutron star that holds the ‘universal’ record of the object with the strongest magnetic fields in the cosmos. For a star to become a magnetar, astronomers initially thought that it had to be really massive. Not quite, actually.
Scientists have been studying HD 45166 for more than a century. Little is known about the true nature of this star other than the fact that it is rich in Helium, it is more massive than our Sun and is part of a binary system.
Using several telescopes, including the Canada-France-Hawai‘i Telescope (CFHT), on Mauna Kea, a team of international researchers began to look deeper into the ‘strangeness’ of HD 45166. Its features are strikingly similar to that of a Wolf-Rayet star, but HD 45166 has a different spectral signature altogether. Astronomers became super curious and began to trace the reason behind the unusual nature of this star. Eureka!
It turns out HD 45166 is magnetic. New data of the star when observed from a ‘magnetic point-of-view’ showed it has a powerful magnetic field, about 43,000 gauss — the most powerful ever found in a massive star. Scientists think that this star might as well be on its journey to become a magnetar. A million years from now, HD 45166 will explode as a bright supernova. Its core will shrink and start trapping all the star's powerful magnetic field lines, creating a highly magnetic neutron star —a magnetar — with a magnetic field of 100 trillion gauss.
Using the telescopes, the team also measured HD 45166's exact age and mass. Scientists think the star formed by the merger of a pair of other intermediate-mass stars. The new research sheds light on how these magnetic powerhouses form and how, unlike previously thought, much less massive stars can also become magnetars under the right conditions.
Image: This artist's impression shows a highly unusual star that is destined to become one of the most magnetic objects in the Universe: a variant of a neutron star known as a magnetar. Credits: NOIRLab/AURA/NSF/P. Marenfeld/M. Zamani