Astronomers have discovered a new type of star, and it appears to be a major clue in solving a long-standing cosmic mystery. This massive helium star has an ultra-strong magnetic field, meaning it could be the preliminary stage of a magnetar – a dense stellar husk that so far has unknown origins.
HD 45166 is a binary star system about 3,000 light-years from Earth, in the constellation of Monoceros. Its primary star is large and mostly made of helium, and observations suggested that it had some unexplained properties. So astronomers investigated it closer, using a range of instruments around the world.
This new data revealed that the star has an ultra-strong magnetic field of 43,000 gauss – the Sun’s, by comparison, is a mere 10 gauss. That makes the primary star of HD 45166 the most magnetic massive star ever found.
“It is exciting to uncover a new type of astronomical object,” said Tomer Shenar, lead author of the study. “Especially when it’s been hiding in plain sight all along.”
Not only is this discovery a brand new kind of star, but it may help explain another astronomical anomaly – neutron stars with incredibly strong magnetic fields, known as magnetars. A few dozen of these objects have been confirmed so far, and while they’re believed to be formed when massive stars collapse, it’s unclear why only some gain intense magnetic fields and become magnetars, while others don’t and become regular neutron stars.
By their calculations, the team believes that HD 45166 will most likely collapse into a magnetar when it dies, gaining an even stronger magnetic field – an unfathomable 100 trillion gauss. Further observations could reveal other, similar stars that seem to be magnetar progenitors, which could answer the question of where they come from.
The research was published in the journal Science. An animation illustrating what the star may look like can be seen in the video below.
Artist’s animation of HD 45166, the most magnetic massive star ever found