Today we’re gonna take a look at what Pulsars
are – and no, I don’t mean the bike; So
Let’s move along;
Pulsars are rotating neutron stars observed
to have pulses of radiation at very regular
intervals that typically range from milliseconds
to seconds.
Maybe you’ll remember, we’ve discussed
the topic of neutron stars in a previous video,
link’s in the description.
Pulsars have very strong magnetic fields which
funnel jets of particles out along the two
magnetic poles.
These accelerated particles produce very powerful
beams of light.
Dame Susan Jocelyn Bell Burnell is an astrophysicist
from Northern Ireland who, as a postgraduate
student, co-discovered the first radio pulsars
in 1967.
She was credited with "one of the most significant
scientific achievements of the 20th century”.
The first pulsar was observed on November
28, 1967, by Jocelyn Bell Burnell and Antony
Hewish.[4][5][6] They observed pulses separated
by 1.33 seconds that originated from the same
location in the sky, and kept to sidereal
time.
The events leading to the formation of a pulsar
begin when the core of a massive star is compressed
during a supernova, which collapses into a
neutron star.
The neutron star retains most of its angular
momentum, and since it has only a tiny fraction
of its progenitor's radius (and therefore
its moment of inertia is sharply reduced),
it is formed with very high rotation speed.
A beam of radiation is emitted along the magnetic
axis of the pulsar, which spins along with
the rotation of the neutron star.
The magnetic axis of the pulsar determines
the direction of the electromagnetic beam,
with the magnetic axis not necessarily being
the same as its rotational axis.
This misalignment causes the beam to be seen
once for every rotation of the neutron star,
which leads to the "pulsed" nature of its
appearance.
Three distinct classes of pulsars are currently
known to astronomers, according to the source
of the power of the electromagnetic radiation:
Rotation-powered pulsars, where the loss of
rotational energy of the star provides the
power.
Accretion-powered pulsars (accounting for
most but not all X-ray pulsars), where the
gravitational potential energy of accreted
matter is the power source (producing X-rays
that are observable from the Earth).
Magnetars, where the decay of an extremely
strong magnetic field provides the electromagnetic
power.
Although all three classes of objects are
neutron stars, their observable behavior and
the underlying physics are quite different.
There are, however, connections.
So that’s it for now, everybody; Subscribe
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Vibrant Violator signing off!
