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we offer and classes released each season. Welcome, my name is Janine and in this video we're going to
focus on the different types of celestial objects that can be found within the boundaries of Cygnus.
Cygnus is an ancient constellation, and its name is Latin for 'Swan'. There are lots of celestial objects
in this particular constellation to view because it sits within the Milky Way galaxy. In fact
the first black hole ever detected was labeled Cygnus X-1, and found within this region of the sky.
So when can you see Cygnus? It's best seen in the northern hemisphere during the late summer months
and into the early autumn months. The best way to find it is to look for the Summer Triangle asterism,
and the tail of the swan, with the star known as Deneb is part of this
asterism. So in this video we're going to focus on the different types of nebulae, planetary nebulae,
black holes, and other objects that are in the boundaries of this constellation. If you want to
learn more about how to find this constellation in the sky be sure to go visit that video.
Now let's dive in and look at the celestial objects within Cygnus.
We're going to break this down a bit. First we'll start with star clusters, move on to nebulae,
take a look at some of the galaxies within Cygnus, and then finally we'll end with looking at some
stellar nurseries and black holes. Now these are objects that would be invisible to the unaided eye
but with special scientific equipment we're able to see and detect these different types of objects.
Here we have a star map of Cygnus, and while it does show the pattern that Cygnus makes across the
sky it also shows a variety of different celestial objects within its boundaries, and remember that
Cygnus is not just the star pattern but it's all the stars that are within this boundary right here.
This star map also shows the Milky way, kind of shaded in purple here, and there's also star
clusters, a planetary nebula, there's some galaxies, up here, so there's a wide variety of objects that
can be seen. Some of these you're going to see with the unaided eye, others would need instrumentation
like a telescope, and some of the ones we'll take a look at there's no way humans can see them without
any type of scientific instruments. So first we'll start with some of the star clusters.
The two that are worth trying to find are Messier 39, right here, this is an open star cluster,
and Messier 29, this is also an open star cluster. If you want to learn more about
the different types of star clusters that there are please go see that video. These are ones that
if you have a pair of binoculars you should be able to find, and it's possible if you're in an
area that has very little light pollution you can see these with the unaided eye.
Next we'll take a look at the nebulae that are situated in Cygnus, and there is a lot to look at,
we're not going to cover everything but we'll go over the main ones.
So here I highlighted some of the ones that you should be able to identify either with a telescope,
or if you're an astrophotographer and you're taking pictures of the sky these are some great
areas to just focus on. So if we were going to name these, we're going to kind of go in this order.
We'll start at the North America nebula, which is actually a very large nebula, and then we'll
go to the Cocoon nebula, which is located over here very close along the border of the of the
pattern of Cygnus, and then we have the Blinking nebula right here, we have the Crescent nebula
which is very close to Seder, and then in this area is probably one of my favorites to look
at and this is the Cygnus loop, which is broken down into many celestial objects.
There's the Western Veil, and the Eastern veil, sounds like something from Game of Thrones, but
we're going to take a look at each of these celestial objects. So first we'll start
with NGC 7000, and this is known as the North America nebula. So, many nebulas are named or
given nicknames after what they resemble and perhaps you can kind of see its resemblance to
the North American continent. It lies very close to the Deneb, and it covers a really large area, more
than four times the size of the full Moon, but its brightness is pretty low. So you're not typically
going to be able to see it with the unaided eye. Astronomers are able to see this by taking long
exposure photographs of this area, and that's how those gases are able to come out over time.
It's estimated to be 1,500 light years from Earth, and it's classified as an emission nebula.
I have another photo I wanted to show you here too, this um this is a compilation by NASA JPL
in Caltech, and you can see the different types of wavelengths that we're looking at here, like
down here we have the infrared lights, here we have visible light, there's x-ray radio. So
I find this an interesting, an interesting picture because it shows you the multiple
frequencies in which we look at objects, and often the pictures that we are observing um when we look
at pictures from NASA and all kinds of other telescopes are usually kind of a collection
of everything that we are seeing. It could be visible, infrared, UV. It's usually
just a combination of all these different types of wavelengths and frequencies that we put together,
and we do this in order to see more definition and to see what is inside, and as we'll learn
later in the video sometimes we can only detect certain objects by using a type of frequency.
So our next object is called IC 5146, and this is dubbed the Cocoon nebula. It's an emission nebula
that's estimated to be 2,500 light years away. So here is where this one is located, so um remember
that constellations aren't just the star patterns they make in the sky but rather they're kind of
like borders of countries, so this is a portion of Cygnus that's right very close to the border
of this constellation. so this is what this one looks like in the sky. This is a long exposure
photograph and it really is beautiful and you can see in here this is estimated to be,
you know it has stars that are that are within this nebula here. Their next one is NGC 6826, this
is known as the Blinking nebula, and this one's a little different than the other ones we looked at
because it's a planetary nebula, and how do we know that is because of its shape. It has this
spherical shape, it has a star right in the center of it, and this is usually a white dwarf star.
So this is a a system that's at the end of its life, this used to be a star that's undergoing
fusion, but it has since run out of fuel, it's run out of hydrogen, it's run out of helium, so then
it starts to expel its layers, and then within it is the white dwarf core that's left over, and the
white dwarf is very very hot and glows not due to fusion but because of incandescence because it's
just so hot, and then here you can see um usually there's kind of jets that come out from the core.
We scientists often study planetary nebula and compare them to see how they're different.
So why is it called the Blinking nebula? Because some nebulae exhibit this type of blinking when
you're observing it. So the central star can kind of overwhelm your eye when you're
viewing it directlym and then the other part parts of the nebula may not shine through, but um that's
just one one example of a planetary nebula. This one's estimated to be 2,000 light years away.
So next we have NGC 6888, and this one's dubbed the Crescent nebula and this has a very interesting
story of its formation, one that I'm kind of wrapping my brain around. It's classified
as an emission nebula, so it's glowing due to um the hot gas that's around it, and it's estimated to
be 5,000 light years away, and this one is located close to Seder. So if you want to try to capture it
that's where you're going to need to, and this is a long exposure photograph so it's very possible you
may not see this one at all unless you have the right equipment to do so. So how did this one form?
It's estimated that um this wolf ryet star, it's a type of star that's um has fast stellar wind,
and it collided with another source of stellar wind, and when they collided it kind of created
these two shock waves, perhaps you can see one here and then one right here. So you've got gases moving
outward from each other, but also inward. So that's maybe confusing to you, that's okay, but know that
every object we look at kind of has its own unique way of forming, and then finally the
last nebulae that we'll look at is called the the Cygnus Loop, and this is a supernova remnant.
The only one we've looked at so far, and it's estimated to be 2,500 light years away, although
because of the orientation of this object the different parts can vary in terms of its distance.
So this supernova remnant was an old star that basically blew up, and it's so large
that astronomers usually pick a particular area to focus on, like this object right here is one,
it's actually two NGC numbers, this is another one, um, and I'll show you this. This is um the Cygnus
Loop labeled with all its different areas. So this old star blew up and it happened over
5,000 years ago, and it's still expanding to this day. So scientists estimate that the approximate
center is right in this area, and these are just all the layers that are continuing to move outward
from this center, and away, okay, so um the reason that all these images are combined is when we're
combining radio infrared and x-ray images, we combine them to really just see the entire
loop. So it's broken down, we'll take a look at some of this, we have the Western Veil nebula,
and this one's dubbed NGC 6960. I love this photo, I just think it looks so cool. You can
just kind of see the movement happening here. You can kind of see that the shock waves are moving
down towards the top of the photograph. So they're moving in this direction.
I often ask my students 'So, in which way do you think the gas is moving and why?'
So this one just clearly demonstrates how the gas is moving is moving outwards. The Eastern Veil
nebulous two different objects NGC 6995 and 6992. This is again just part of that Cygnus loop, and
you can see again this time it's probably moving in this direction, it's moving in this direction.
Next we'll explore the galaxies that sit within Cygnus. So the first is called Cygnus A, and
Cygnus A doesn't have many visible galaxies and that's because they are obscured by gas and dust
within the Milky Way, but Cygnus A is classified as a radio galaxy, and it's one of the strongest
radio sources in the sky, and that's how it was first detected, were not by light but by
the radio waves it was sending out. So that's what you're seeing here, you've got um this is the core
of the galaxy and then we're seeing different radio signals that are put into a picture for us.
So it is the closest powerful radio galaxy, and when we're looking at it on the on the spectrum
on the visible spectrum, it appears to be an elliptical galaxy, and it has a super massive
black hole at the core that produces these long, these very long jets of matter from its poles.
So again very interesting, um you know that the fact that we're able to detect galaxies simply
by the radio waves they're giving off. The next one is called NGC 6946. So if we're looking at Cygnus
right here this galaxy is right up on the border of of the boundary of Cygnus, and it's a spiral
galaxy and it's estimated to be 22 million light years away. Now the reason it's it's got the name
Fireworks Galaxy is because there are a large number of supernovas that have been that have
been exploding in the arms of this galaxy. In the past century we've observed at least eight,
so when the Chandra Observatory, which really looks at the x-ray portion of the
electromagnetic spectrum revealed that there are three really old supernovas that we were able
to detect using x-rays. So that just goes to show you um how it got its name is just that there are
lots of supernovas happening um or that have happened within the arms of the scally and
or this arms of this galaxy, so the fact that we were able to detect it is really fascinating.
So finally we're going to take a look at the hidden celestial objects that we may not be
able to see with their eyes, but have been detected by other means, and this includes stellar nurseries
and black holes. So the first is Cygnus X, and this is a massive stellar nursery, in fact it is the
area that has the most amount of star formation in our galaxy, and this area is difficult to to detect
because it's often hidden by something called the Great Rift, which we'll talk about in a little bit,
but this area is estimated to be 4,600 light years away, and there are just so many things happening
here, it's massive areas of star formation and you can actually see little pockets in here,
sometimes there's bubbles that are created, and um massive massive stars are forming in here. So
this area spans over 600 light years across, and it contains over a million times the mass of our sun.
So it's very interesting, this is situated in Cygnus and it's estimated to be like in a
few million years star formation will slow, and then the stars will start to disperse
themself over time. So the Great Rift is the area that actually hides Cygnus X. So Cygnus X
is this is a deep infrared image, so it's not quite taken with visible light but rather infrared,
and the great rift is this dark lane that divides the band of our Milky Way. So you can probably see
where that is. This is that dark band that we're talking about, the Great Rift, and it goes
even into here, right there, and then this band starts in Cygnus. So here is where Cygnus is
located, and then it goes all the way towards Aquila, this is where Aquila is, and then it
goes into Ophiuchus, and then into Sagittarius. So this cloud, this molecular dust cloud really
obscures the center of our galaxy. So it's just blocking light from able to pass through it, so
the Great Rift is is part of this feature that is that is going through Cygnus, and I just wanted to
bring your attention to it because the Great Rift really expands across a large portion of the sky.
The next object I wanted to talk to you about was Cygnus X-1, and this was the very first black
hole that was ever detected and it was detected by using x-rays. It really is still one of the
strongest x-ray sources that we have seen from Earth. So this object, which this is kind of an
x-ray view of it, is estimated to be 14.8 times the mass of our own own sun, yet is only 44 kilometers.
So that's just, it's almost mind-boggling that there could be something 14 times the mass of our
sun but in a smaller area. So it was accepted by the the scientific community that this was a black
hole, and then this is the arena in which it is located. So remember we can't see black holes, well
that's not technically true, but for the longest time we weren't able to really see black holes. We
were only able to detect them through x-rays, and black holes give off x-rays when material enters
inside of it past the event horizon, and it gives off these big jets of light
or not light but rather x-rays. So here's another picture of the area of Cygnus X-1.
This was taken by the Chandra x-ray Observatory. So just another view of what this area
looks like, and only very very recently in 2019 have we been have we been able to
actually get a picture of a black hole, and this took the work of many many scientists.
Thank you so much for watching this video about Cygnus, and all the amazing celestial
objects that sit within the boundaries of this constellation. Remember any time you're learning how
to stargaze it takes time, patience, and practice. So make a point to go outside, and do it regularly
so you can just absorb the beauty of the stars. I wish you luck going outside and keep looking up!