Scientists have discovered the most powerful magnetic star in the universe. The star, known as HD 45166, has a unique helium-rich spectral signature, showing how it formed is particularly unusual. In addition to setting records, this star can be considered a good example of the first stage in the life of a magnetic star – or can be considered a strange type of neutron star.
Neutron stars are the densest known objects in the universe, ‘cramming’ an entire Sun-equivalent mass into a sphere just as wide as a city on Earth. Their highly magnetic versions – known as magneto stars – possess the strongest known magnetic fields in the universe. Neutron stars and magneto stars form after massive supernova explosions, when matter left over from a dead star condenses into an extremely dense and hot object.
But astronomers are still trying to figure out what makes magneto stars compared to regular neutron stars. New research published in Science on August 17 may shed light on that process.
Located 3,000 light-years from Earth in the constellation Monoceros (the Unicorn), HD 45166 has puzzled scientists for more than a century. This star behaves similarly to a class of extremely bright stellar objects known as Wolf-Rayet stars, except that it is smaller, dimmer, and has an unusually high concentration of helium. However, so far no one has come up with a satisfactory hypothesis to account for its strange spectral signature.
Tomer Shenar, an astronomer at the University of Amsterdam and co-author of the new study, said in a statement: “I remember having an Eureka moment when reading the material: ‘What if this star magnetic?'”. Using data from several ground-based observatories, Shenar and his team found that HD 45166 has an extremely strong magnetic field – with a magnetic strength up to 43,000 times stronger than the Sun – a record in the universe.
The researchers suspect that, unlike most helium giants that evolved from red supergiants, HD 45166 was formed during a merger between two smaller stars. They also believe that in a few million years, it will explode into a modest supernova and re-form a magnetic star.
“This is a very specific case,” said astronomer André-Nicolas Chené, co-author of the study.
“It raises the question of how many magneto stars come from similar star systems and how many come from other types of star systems,” he said. Meanwhile, this newly studied magnetron represents a new type of stellar object never seen before – a giant magnetic helium star.
Refer to Live Science