Greetings and welcome to the
Introduction to Astronomy.
One of the things
that I like to do
in each of my introductory
astronomy classes
is to begin the class with the
astronomy picture of the day.
From the NASA website that
is APOD.NASA.GOV/APOD.
And today's picture for
December the 18th of 2019.
Well, it is titled a Hotspot
Map of Neutron Star J0030's
Surface.
So what do we see here?
Well, by using an X-ray
telescope attached
to the International
Space Station,
we are able to make
a model of hot spots
on a neutron star
1,000 light years away.
So when we look here, these
are some images or models
of what the neutron star would
look like based on the X-ray
variations.
Now a neutron star itself
is what forms in a supernova
explosion when the core is
compacted down about as tight
as matter can possibly
be compressed.
And essentially what happens
is that all the electrons
get pushed into the
nucleus of the atom.
They combine with protons
and create neutrons.
So essentially, it
is a great big ball
of neutrons with the density
of an atomic nucleus.
So incredibly dense compared
to anything he anything here
on earth, you could not
even you could not even
walk on the planet you'd
be immediately crushed
if you were to walk
on this star ignoring
of course, the very
high temperatures that
would vaporize you.
But anything there would be
crushed down to the surface.
And in fact, a neutron
star is just a little bit
away from being a black hole
where it crushed a little bit
more than even light would
not be able to escape from it.
So trying to study
these objects being
so small about the size of
a city several miles across
is very difficult
because you can't
get any kind of images of them.
It's hard enough to
image a star directly
let alone something
that is so small.
Good located at such
a distance, but one
of the things we
can learn about them
is that they do spin very
rapidly and in fact, this one.
Spins a couple
times every second.
And that allows us to
use the X-ray emissions
from these hot spots
to kind of map them out
and to see where
they are located.
Now that will help us
learning about those
is going to help us learn
about the different properties
of neutron stars such as how
big they are, how much mass,
they contain and how they
are actually held together
or these things spin so rapidly.
You might expect them
to just tear themselves
apart from the
forces of that spin
and they are not
they are dense enough
that they are able to hold
together even spinning 200
times a second as you can
imagine with the earth
to try to spin 200
times a second,
it would eventually would just
be shredded by those forces.
So these things are able to do.
And we're learning something
about their physics of physics
of a neutron star to
understand what they are like
and how they work.
So at this point, we can
only map the hotspots,
the bright white objects
that you see on the image
the rest of it is
just shading to cover
the rest of the neutron star.
So the only things that we're
really learning about right now
are these hot spots.
But trying to
understand why there
are specific hot spots
on the neutron star
will help give us a better
understanding of these objects.
So that was our picture of
the day for December the 18th
of 2019.
It was titled A Hotspot Map of
Neutron Star J0030's Surface.
We'll be back again tomorrow
for the next picture.
So until then have a
great day, everyone.
And I will see you in class.
