Our Sun has a strong magnetic field but there are stars out there with much strong magnetic fields, way beyond what they should have. Stars many times the size and mass of the Sun are expected to have proportionally larger magnetic fields, but these stars go way beyond. They are hypermagnetic stars! Up until recently we were at a loss to explain how they come to exist.
Magnetic fields are produced in stars due to their spinning cores propagating electrical charges. Moving electrical charges produce a magnetic field. In the case of stars, layers just outside the core are also spinning, but more slowly and they produce magnetic fields as well. Layers above move more slowly still. These differential motions from the core upward cause magnetic fields to get very twisted and as they emerge from the star’s surface, they produce a variety of phenomena. Prominences, spots, even coronal mass ejections occur when these magnetic fields merge and explode out of a star’s surface. They make stars like our Sun the dynamos they are.
Recent research by a German-British team has shed some light on how hypermagnetic stars form. Seems it takes two stars to make one. On the surface it doesn’t seem intuitive that two stars come much closer to hypermagnetic status than one. Things get interesting when two run of the mill stars (like our Sun) merge into one bigger star. This merger juices up the magnetic field of the resulting star so much it becomes a wild child with a magnetic field one hundred times or more than the Sun’s. These stars make our Sun appear lame. That’s one wild star!
Their research produced additional finds.
One regards stars called Blue Stragglers. Blue stragglers are oddball stars. They are main sequence stars that appear too young for their makeup – they contain more heavier elements than a young star should. This team has proposed the merger solution for explaining blue stragglers. Two older, red giant main sequence stars could merge with a resulting reboot of hydrogen fusion, making them bigger, hotter, and blue!
Another find might explain the existence of the most intense magnetic field we know, that of the magnetar. Magnetars appear to be perverse neutron stars, with magnetic fields so strong and wild they can barely contain themselves enough to keep from coming apart at the seams. They spew x-rays and gamma rays like a screaming, spittle spewing politician. Magnetars might be the result of monster blue stragglers going supernova. The unanswered question is whether the magnetic field can survive the core collapse and supernova blast resulting in a neutron star.
So, a merger of red giants might ultimately explain the phenomenon of Fast Radio Bursts, short, extremely energetic signals coming from deep space.
What’s in the Sky?
February 3; after sunset; southeast: A waxing Moon is in Taurus, close to Aldebaran
February 7; after sunset; west-southwest: Venus high and Mercury close to the horizon