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MARK HARTMAN: And this is an
animation of what they actually

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think is going on.

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So I'll give you
the basics about it.

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But if you want
to, I encourage you

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to read through all of this.

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But in this case,
this yellow object

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is the thing that's
giving off X-rays.

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And it's not the neutron
star itself, right?

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It's actually a
big cloud that is

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kind of like a corona
around a regular star,

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but we have a corona
around a neutron star,

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and it's many,
many times larger.

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So that's giving off X-rays.

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This is the edge of
the accretion disk.

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And you can see
that it's not always

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the same thickness, right?

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So the edge of
the accretion disk

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is actually blocking out
some of the X-ray emission

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from this object.

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So they're still not exactly
sure where all the X-ray

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emission is coming from.

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But you're seeing, then,
the companion star,

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which is a low mass
star, is orbiting around.

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But what I want you to do
is just take a look at this.

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So this is the edge
of the accretion disk.

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[? So ?] the yellow thing is the
corona around the neutron star,

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and the blue thing is
the low mass star that's

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not giving off X-rays.

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So read through
that a little bit.

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And I want you to think about--

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I mean, pay close attention.

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What is it that's
causing that first dip?

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What's causing the second dip?

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I'm sorry you can't
slow this down any.

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But this is what a
real science team

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had come out with as a model
for what they think is going on.

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And they're showing here
the actual light curve

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over and over and over again.

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And they're saying,
this is the best model.

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We changed a bunch
of parameters.

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We decided this is what we
think makes sense to us.

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And as you're looking at
this and thinking back

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about all the X-ray binary stuff
that you have thought about,

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what I want to do is to
have everybody contribute

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at least one question,
hopefully two or three,

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that they have about
X-ray binary [? object. ?]