Mark Megahan
Scientists from New York City to Amsterdam are pacing around like nervous fathers in the waiting room of the maternity ward, as they await the birth of mind-bogglingly powerful magnetic fields. A magical “magnetar” is “on the cusp of forming.”
Massively magnetic objects
Astrophysicists are attracted to magnetar research by their magnetic personalities. These “deceptively pint-sized” stars have no hope of ever becoming a black hole, even though they’re almost as dense. What little mass they have is packed into a tiny ball “no bigger than a city.” What they lack in size, they make up in raw power. We only know of about 30 of them in our galaxy.
Until now, they were considered a type of neutron star. What everyone is waiting for is “HD 45166’s abnormally magnetic Wolf-Rayet star will end its life in a neutron-star-forming supernova, giving rise to a brand-new magnetar.” It can happen anytime “a few million years from now.”
Magnetars are attention grabbing here on earth because of the “mind-bogglingly powerful magnetic fields” they produce. Ones which “are trillions of times stronger than the one that encompasses our planet.” It’s so strong, experts relate, that “it can crack open the star’s surface to release powerful bursts of energy that may be visible across billions of light-years.”
They’re a whole lot more fun to watch than anything else in the universe. Putting it in perspective, “If such a magnetar were placed in the moon’s orbit around Earth, it would wipe most credit cards and hard disk drives on the planet.”
Until now, the experts weren’t really sure how they manage to actually form. As Christopher White of the Flatiron Institute in New York City explains, they “have too many ideas, and we’re not sure which ones are right.” What they just found looks to them like a baby magnetar still in the womb.
Researchers, he notes, “may have pinned down one possible pathway to a magnetar by finding an unusually massive and magnetic star that might be on the cusp of forming one of these enigmatic objects.”
Amsterdam eyeing HD 45166
Tomer Shenar of the University of Amsterdam and his colleagues are focused on “a pair of stars about 3,000 light-years from Earth that are collectively called HD 45166.” One of them has “previously been identified as a Wolf-Rayet star—a very rare, hot and massive star in the final stages of its life.” When they started taking detailed observations they noticed “a magnetic field of 43,000 gauss.” That’s huge.
What makes those stars so interesting is the way they “have exhausted their hydrogen fuel and instead burn helium, which makes them shine brighter and raises intense stellar winds that can blow off their outer layers.” They’ve seen those type of objects before but not like this.
Earth has a magnetic field which protects us from solar flares. Our planet generates 0.5 gauss. The sun’s fusion reaction produces 1.0 gauss. “This makes the star, whose mass is twice that of our sun, the most magnetic massive star ever discovered.” When they got the readings back, the Amsterdam team headed to the closest coffee shop for a bong. Their best guess is that “the star was likely the result of two helium-rich stars merging together.”
Not only that, “We think it was quite a complicated merger. One that possibly involved a helium-rich lower mass star spiraling into the puffy stellar atmosphere of an accompanying red supergiant.” That would work as an amplifier.
“We have never detected magnetic fields in these types of stars,” Shenar says. “It turned out to have an extremely powerful magnetic field, and it is a prime candidate for becoming a magnetar.” They gathered the data with “the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii—along with data from Brazil’s National Laboratory for Astrophysics, La Silla Observatory in Chile and the Roque de los Muchachos Observatory in Spain’s Canary Islands.”
Once they had the numbers, they crunched them with “a process called Zeeman-Doppler imaging, which can tease out details of a stellar magnetic field from subtle changes the magnetism imparts to the polarization of a star’s light.“
