Magnetars are the strongest magnets within the Universe. These super-dense lifeless stars with ultra-strong magnetic fields may be discovered throughout our galaxy however astronomers do not know precisely how they kind. Now, utilizing a number of telescopes around the globe, 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 sort 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 standard fashions, and little was recognized about it past the truth that it’s one among a pair of stars [1], is wealthy in helium and is a number of instances extra huge than our Solar.

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

Having studied comparable helium-rich stars earlier than, Shenar thought magnetic fields may crack the case. Certainly, magnetic fields are recognized to affect the behaviour of stars and will clarify why conventional fashions failed to explain HD 45166, which is situated about 3000 light-years away within the constellation Monoceros. “I keep in mind having a Eureka second whereas studying the literature: ‘What if the star is magnetic?’,” says Shenar, who’s at present based mostly on the Centre for Astrobiology in Madrid, Spain.


Shenar and his staff got down to research the star utilizing a number of amenities across the globe. The primary observations had been performed in February 2022 utilizing an instrument on the Canada-France-Hawaii Telescope that may detect and measure magnetic fields. The staff 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 had been in, Shenar requested co-author Gregg Wade, an knowledgeable on magnetic fields in stars on the Royal Navy School of Canada, to look at the info. Wade’s response confirmed Shenar’s hunch: “Properly my buddy, no matter this factor is — it’s positively magnetic.”

Shenar’s staff had discovered that the star has an extremely robust magnetic subject, of 43,000 gauss, making HD 45166 essentially the most magnetic huge star discovered to this point [2]. “Your entire floor of the helium star has a magnetic subject virtually 100,000 instances stronger than Earth’s,” explains co-author Pablo Marchant, an astronomer at KU Leuven’s Institute of Astronomy in BelgiumThis remark marks the invention of the very first huge magnetic helium star. “It’s thrilling to uncover a brand new sort 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 lifeless stars laced with magnetic fields at the least a billion instances stronger than the one in HD 45166. The staff’s calculations recommend that this star will finish its life as a magnetar. Because it collapses below its personal gravity, its magnetic subject will strengthen, and the star will finally turn into a really compact core with a magnetic subject of round 100 trillion gauss [3] — essentially the most highly effective sort of magnet within the Universe.

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


[1] Whereas HD 45166 is a binary system, on this textual content HD 45166 refers back to the helium-rich star, to not each stars.

[2] The magnetic subject of 43,000 gauss is the strongest magnetic subject ever detected in a star that exceeds the Chandrasekhar mass restrict, which is the crucial restrict above which stars could collapse into neutron stars (magnetars are a sort of neutron star).

[3] On this textual content, a billion refers to at least one adopted by 9 zeros and a trillion refers to at least one adopted by 12 zeros.

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