Neutron Stars

Neutron stars Key words

Size

accretion disc exoplanet gamma ray magnestar millisecond pulsar neutron star

By comparing a neutron star with Manhattan Island on the same scale, the neutron star’s very small size can be visualized. neutron star

orbit pole pulsar supernova X-ray X-ray burster

Neutron star

Manhattan Island

neutron star is a small but extremely dense object composed almost entirely of neutrons. ● A neutron star may be only six miles (10 km) in diameter but have between 1.4 and three times the mass of the Sun. ● Neutron stars are thought to be the collapsed remnants of massive stars that have exploded in supernovas. ●A

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Neutron star features ● Neutron

stars rotate very rapidly. The most rapid have rotation periods of hundredths of a second and the slowest of 30 seconds. ● This rapid rotation is due to the conservation of angular momentum: the slow rotation of the original massive star speeds up as the object shrinks. ● Rotation periods very slowly become longer over time: younger neutron stars rotate more rapidly than older ones.

A neutron star is the result of the collapse of a giant star many millions of times larger in size. As a result of this compression, neutron stars are very dense.

A cubic centimeter of matter from a neutron star would weigh about as much as 3,500 fully-laden Saturn V rockets on Earth.

Neutron star types Pulsars ● Pulsars

are neutron stars that emit a stream of X-rays and gamma rays from their poles. These are recorded as regular pulses whenever an observer is in line of sight of one of the poles. ● As with all neutron stars, a pulsar’s rate of rotation slows as time passes. As its rotation slows, the frequency of the pulses is also reduced. ● However, millisecond pulsars are very old pulsars (one billion years or more) with

very high rotation rates (pulse periods of less than 25 milliseconds). ● Millisecond

pulsars are thought to form when material from a companion star falls onto a pulsar, causing it to spin more and more rapidly. ● The first exoplanets to be discovered are in orbit around millisecond pulsars.

are neutron stars with magnetic fields that are at least 1,000 times more intense than Earth’s. Their magnetic fields become weaker over time. ● X-ray bursters are neutron stars that have accretion discs formed from material drawn from orbiting companion stars. Friction in the accretion disc results in the periodic emission of powerful X-ray bursts.

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● Magnestars