Magnetar

A magnetar is a very strong star.

It has a giant pull. This pull is much stronger than a magnet on your fridge.

A big star must die to make one. When the star falls in on itself, it becomes small and heavy.

One tiny spoonful would weigh a lot!

These stars spin very slowly. They also make bright flashes of light. These flashes can be seen from far away.

They are very special stars in space.

A magnetar is a special kind of neutron star.

It has an extremely strong magnetic field. This field is a hundred million times stronger than any magnet made by people.

Magnetars form when a very big star dies. The star collapses in on itself. This makes a small, heavy object. A single tablespoon of this star would weigh over 100 million tons!

These stars spin more slowly than other neutron stars. Most magnetars spin once every two to ten seconds. Their strong magnetic fields also make bright flashes. These are called gamma rays. These rays are a type of high-energy light.

Sometimes, starquakes happen on the surface. These shakes cause huge bursts of light. In 1979, a giant burst was seen from a star far away. Scientists think magnetars might also cause fast radio bursts. These are quick flashes of radio waves from space. We have confirmed 24 magnetars so far.

A magnetar is a very special type of neutron star.

These stars are famous for having extremely powerful magnetic fields. Their magnetism is a hundred million times stronger than any magnet made by people. It is also a trillion times more powerful than the field around Earth. This magnetic force is so strong it can change the shape of atoms. A hydrogen atom would become 200 times narrower than usual. Even from far away, these fields are very intense.

These stars form when a huge star dies and collapses. The original star must have a mass 10 to 25 times that of our Sun. When it collapses, it creates a tiny but very heavy object. A magnetar is about the same diameter as other neutron stars. However, it has a mass of about 1.4 solar masses. The material inside is incredibly dense. Just one tablespoon of this substance would weigh over 100 million tons.

Scientists first proposed the idea of magnetars in 1992. Robert Duncan and Christopher Thompson suggested they existed to explain certain gamma rays. These rays come from sources called soft gamma repeaters, or SGRs. Over the next ten years, most scientists accepted this idea. Later, the theory helped explain something called anomalous X-ray pulsars. In 1979, a massive burst of gamma radiation was detected by many space probes. This event, named GRB 790305b, came from a star in the Large Magellanic Cloud.

There are several interesting facts about how magnetars behave. Most magnetars rotate slowly, once every two to ten seconds. This is much slower than typical neutron stars that spin many times per second. Their active life is quite short, lasting about 10,000 years. After this time, their magnetic fields decay and the bright X-ray light stops. Scientists have confirmed 24 magnetars so far. Some think there might be 30 million inactive magnetars in our Milky Way galaxy.

Magnetars connect to things we see in our own world. For example, a magnetar's field is much stronger than a neodymium magnet. If a magnetar were halfway between Earth and the Moon, it could wipe the information from all credit cards on Earth. They also cause starquakes on their surfaces. These shakes disturb the magnetic field and create huge bursts of light. In 2020, scientists used the ASKAP radio telescope to link magnetars to fast radio bursts. These are quick flashes of radio waves from deep space.

A magnetar is a rare and extreme type of neutron star.

These objects are defined by their incredibly intense magnetic fields. These fields range from approximately 10^9 to 10^11 Tesla. This makes them the most powerful magnetic objects ever detected in the universe. The energy from the decay of these magnetic fields powers the emission of high-energy electromagnetic radiation. This radiation mostly appears as X-rays and gamma rays. Because of this unique energy source, magnetars are vital for understanding high-energy physics in space.

Magnetars form through the dramatic collapse of massive stars. To create one, a star must have a mass between 10 and 25 times that of our Sun. When such a star dies in a supernova, it collapses into a dense neutron star. A magnetar has a mass of about 1.4 solar masses. Despite this mass, its diameter is similar to other neutron stars. The density is staggering. A single tablespoon of magnetar material would weigh over 100 million tons.

There are different ways scientists think these magnetic fields become so strong. One dominant model is the magnetohydrodynamic dynamo process. This occurs in the turbulent, dense, conducting fluid present before the star reaches equilibrium. This process converts heat and rotational energy into magnetic energy. This can boost a field from 10^8 Tesla to over 10^11 Tesla. An alternative model suggests they simply result from the collapse of stars that already had unusually strong magnetic fields. Once formed, these fields may persist due to currents in a proton-superconductor phase deep inside the star.

Magnetars differ from typical neutron stars in several specific ways. First, their magnetic fields are vastly stronger. A magnetar's field is about a trillion times more powerful than Earth's geomagnetic field. Second, they rotate much more slowly. Most observed magnetars rotate only once every two to ten seconds. In contrast, typical radio pulsars can rotate one to ten times every single second.

Their active life is also quite short. After about 10,000 years, the magnetic field decays and the strong X-ray emissions cease.

History shows how our understanding of these stars has grown. In 1992, Robert Duncan and Christopher Thompson proposed the magnetar hypothesis. They wanted to explain transient gamma-ray sources called soft gamma repeaters (SGRs). The theory later helped explain anomalous X-ray pulsars (AXPs). A major breakthrough occurred on March 5, 1979. Several space probes, including Soviet Venera 11 and 12 and NASA's Helios 2, detected a massive gamma-ray blast. This event, named GRB 790305b, was the first observed SGR megaflare. It originated from SGR 0525−66 in the Large Magellanic Cloud.

The physical effects of such magnetism are mind-boggling. At a distance of 1,000 km, the field would be lethal to life. It distorts the electron clouds of atoms, making chemistry impossible. A hydrogen atom at 10^10 Teslas becomes 200 times narrower than its normal diameter. If a magnetar were halfway between the Earth and the Moon, it could wipe the magnetic stripes from every credit card on Earth.

Even the vacuum of space becomes polarized and acts like a calcite crystal.

Scientists have confirmed 24 magnetars, but many more likely exist. Some estimates suggest there are 30 million inactive magnetars in the Milky Way. Notable examples include SGR 1806−20, which is the most magnetized object known. Another, SGR 1900+14, has a surrounding ring of matter 7 light-years across.

In 2020, researchers using the Australian Square Kilometre Array Pathfinder (ASKAP) suggested magnetars might cause fast radio bursts (FRB). This connects these extreme stars to other mysterious signals in our cosmos.