This diagram of a pulsar shows the neutron star with a strong magnetic field field lines shown in blue and a beam of light along the magnetic axis.
As the neutron star spins, the magnetic field spins with it, sweeping that beam through space. If that beam sweeps over Earth, we see it as a regular pulse of light.
Your browser does not support the video tag. Download the movie. This animation takes us into a spinning pulsar, with its strong magnetic field rotating along with it.
Clouds of charged particles move along the field lines and their gamma-rays are beamed like a lighthouse beacon by the magnetic fields. As our line of sight moves into the beam, we see the pulsations once every rotation of the neutron star.
A rupture in the crust of a highly magnetized neutron star, shown here in an artist's rendering, can trigger high-energy eruptions. They could also enhance the magnetic field produced from the flux conservation, a bit like an ultra-ferromagnetic material. I believe that it's overlooked, actually. It may be a macroscopic feature of the neutron Fermi fluid.
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Dave's Universe Year of Pluto. Groups Why Join? Astronomy Day. The Complete Star Atlas. If a neutron star emits photons, where would they come from, and would they not experience the Zeeman effect? Why are neutron stars called stars? Good questions! Neutron stars are magnetic because their interiors contain powerful electrical currents. In that sense, they have more in common with electromagnets, which are associated with electric fields, than with toy magnets, which are permanent magnets and require no electric field to incite their magnetic properties.
The Zeeman effect is a splitting of atomic lines due to magnetic fields. How to blow up a star. NICER detects these X-rays using 56 gold-coated telescopes, and time-stamps their arrival to within nanoseconds. With this capability, researchers can precisely track hotspots as a neutron star whips around at up to 1, times per second.
Hotspots are visible as they swing across the object. That and other observations allow astrophysicists to pin down the masses and radii of the deceased stars. Those two properties could help in determining what is happening down in the cores. Neutron stars get more complicated the deeper one goes. Beneath a thin atmosphere made mostly of hydrogen and helium, the stellar remnants are thought to boast an outer crust just a centimetre or two thick that contains atomic nuclei and free-roaming electrons.
Researchers think that the ionized elements become packed together in the next layer, creating a lattice in the inner crust. Physicists have some idea of what happens, thanks to particle accelerators on Earth. But these kinetic experiments generate billion- or even trillion-degree flashes, in which protons and neutrons dissolve into a soup of their constituent quarks and gluons. Terrestrial instruments have a hard time probing the relatively mild millions-of-degrees conditions inside neutron stars.
There are multiple ideas about what might occur. It could be that quarks and gluons roam freely. Or, the extreme energies could lead to the creation of particles called hyperons. Like neutrons, these particles contain three quarks. Another possibility is that the centre of a neutron star is a Bose—Einstein condensate, a state of matter in which all subatomic particles act as a single quantum-mechanical entity.
And theorists have dreamt up even more outlandish prospects, too. Colliding stars spark rush to solve cosmic mysteries. They would generate different internal pressures and therefore a larger or smaller radius for a given mass. A neutron star with a Bose—Einstein condensate centre, for instance, is likely to have a smaller radius than one made from ordinary material such as neutrons.
One with a core made of pliable hyperon matter could have a smaller radius still. They typically estimate masses by observing neutron stars in binary pairs.
As the objects orbit one another, they tug gravitationally on each other, and astronomers can use this to determine their masses. Roughly 35 stars have had their masses measured in this way, although the figures can contain error bars of up to one solar mass.
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