New type of star gives clues to mysterious origin of magnetars

Magnetars are the strongest magnets within the universe. These super-dense useless stars with ultra-strong magnetic fields could be discovered throughout our galaxy however astronomers do not know precisely how they kind.

Now, utilizing a number of telescopes all over the world, together with European Southern Observatory (ESO) amenities, researchers have uncovered a residing star that’s prone to turn into a magnetar. This discovering marks the invention of a brand new kind of astronomical object—huge magnetic helium stars—and sheds mild on the origin of magnetars.

Regardless of having been noticed for over 100 years, the enigmatic nature of the star HD 45166 couldn’t be simply defined by typical fashions, and little was recognized about it past the truth that it’s considered one of a pair of stars, is wealthy in helium and is a number of occasions extra huge than our sun.

“This star turned a little bit of an obsession of mine,” says Tomer Shenar, the lead creator of a examine on this object revealed in Science and an astronomer on the College of Amsterdam, the Netherlands. “Tomer and I discuss with HD 45166 because the ‘zombie star,'” says co-author and ESO astronomer Julia Bodensteiner, primarily based in Germany. “This isn’t solely as a result of this star is so distinctive, but additionally as a result of I jokingly stated that it turns Tomer right into a zombie.”

Having studied related helium-rich stars earlier than, Shenar thought magnetic fields may crack the case. Certainly, magnetic fields are recognized to affect the conduct of stars and will clarify why conventional fashions failed to explain HD 45166, which is positioned about 3,000 light-years away within the constellation Monoceros. “I bear in mind having a Eureka second whereas studying the literature: ‘What if the star is magnetic?’,” says Shenar, who’s presently primarily based on the Middle for Astrobiology in Madrid, Spain.

Shenar and his group got down to examine the star utilizing a number of amenities across the globe. The primary observations have been performed in February 2022 utilizing an instrument on the Canada-France-Hawaii Telescope that may detect and measure magnetic fields. The group additionally relied on key archive knowledge taken with the Fiber-fed Prolonged Vary Optical Spectrograph (FEROS) at ESO’s La Silla Observatory in Chile.

As soon as the observations have been in, Shenar requested co-author Gregg Wade, an knowledgeable on magnetic fields in stars on the Royal Navy Faculty of Canada, to look at the info. Wade’s response confirmed Shenar’s hunch: “Nicely my buddy, no matter this factor is—it’s positively magnetic.”

Shenar’s group had discovered that the star has an extremely sturdy magnetic discipline, of 43,000 gauss, making HD 45166 essentially the most magnetic huge star discovered up to now. “Your complete floor of the helium star is as magnetic because the strongest human-made magnets,” explains co-author Pablo Marchant, an astronomer at KU Leuven’s Institute of Astronomy in Belgium.

This commentary marks the invention of the very first huge magnetic helium star. “It’s thrilling to uncover a brand new kind of astronomical object,” says Shenar, “particularly when it has been hiding in plain sight all alongside.”

Furthermore, it gives clues to the origin of magnetars, compact useless stars laced with magnetic fields no less than a billion occasions stronger than the one in HD 45166. The group’s calculations counsel that this star will finish its life as a magnetar. Because it collapses below its personal gravity, its magnetic discipline will strengthen, and the star will ultimately turn into a really compact core with a magnetic field of round 100 trillion gauss—essentially the most highly effective kind of magnet within the universe.

Shenar and his group additionally discovered that HD 45166 has a mass smaller than beforehand reported, round twice the mass of the sun, and that its stellar pair orbits at a far bigger distance than believed earlier than. Moreover, their analysis signifies that HD 45166 shaped by the merger of two smaller helium-rich stars. “Our findings utterly reshape our understanding of HD 45166,” concludes Bodensteiner.