There are an estimated 1,000,000,000,000,000,000,000 (a billion trillion) stars in the observable universe. So, it’s only right that many of them are very different from the norm. Whilst most stars are red dwarfs, main sequence or red super giants – there are a whole collection of star categories that lie outside of the usual. From incredible magnets that could wipe your laptop hard drive from 100 million miles away, to literal ‘strange’ matter, here are just a few of the weirdest and rarest star types in the Universe.
Binary star systems, in which two stars orbit a common central point, are not a special occurrence in our Universe. In fact, the second nearest star to our Sun, Alpha Centauri, is a binary star system that appears as one point of light when viewed from Earth. Contact binaries however, are very special. In these rare cases, two massive stars orbit so close to each other that their gaseous envelopes actually overlap and touch with each other. Although it has never directly been observed, scientists have theorised that some contact binaries may actually have a period of direct surface contact – before they either merge into one supergiant star or explode into a supernova and create a black hole.
Neutron stars are created as a stellar remnant, after a supernova explosion of a giant star. To become a Neutron Star, the exploding giant must have a mass above the Chandrasekar Limit. Below that, the gravitational force of its weight is not enough to force a collapse – meaning the star’s gas will simply leak away into space leaving behind a White Dwarf. If, however, the star is above 8 solar masses it may collapse in on itself and create a Neutron Star or, if it is even heavier, a black hole. These stars may contain 10 times the mass of the Sun, or millions of times that of Earth, in a space barely 10 to 15 miles wide.
Although scientists are not 100% certain exactly what is inside Neutron Stars, we know they are mostly neutrons crushed into a super dense state. One thimbleful of neutron degenerate matter (as it called) would weigh three billion tonnes on Earth, which is roughly the same as a 1.2-mile cubed chunk of Earth.
Magnetars are Neutron Stars with extreme magnetic fields. A typical magnetar has a magnetic field strength of around 1017 Tesla, which is the unit of measurement for magnetic fields. For scale reference, a fridge magnet will have a strength of roughly 0.05 Tesla and Magnetic Resonance Imaging machine, or MRI, will have up to 7. 16 Tesla. A field of around 16 teslas is enough to magnetise the water inside a living animal, such as a frog, causing it to levitate. Even at ten million miles away, the magnetic force of a magnetar would be enough to cause you some serious damage. At thousands of miles away or less, your atoms would be permanently ripped apart. This makes Magnetars one of the most dangerous, and also least understood, objects in the known Universe – and fitting place to end our article.