One of my absolute favorite constellations is Scorpius the scorpion. I'll never forget
the first time I saw this constellation in its entirety. It was one of the first things I saw
when I moved to Hawaii. When I landed in Kona at night and stepped onto the tarmac I looked up and
saw it and was absolutely amazed. Where I grew up there's a mountain to the south of my house so I
often only saw this portion of Scorpius, but when you get to see this constellation in its entirety
it is amazing, and it's one of the first constellations I ever took a picture of. I know
this is kind of grainy, but you can see Scorpius right here, and the thing that stands out with this
constellation is this bright red star that's often called the heart of the scorpion and the name of
that star is Antares, and in this video we're going to learn about the characteristics of the Antares
system, which is a binary pair that contains a red supergiant and a blue main sequence star
and we'll practice how to find it in the sky. Welcome to Learn the Sky. My name is Janine and
I'll be your guide as we explore the night sky together one constellation at a time.
First we'll get a broad overview of the star Antares. It's the 15th brightest star in the night
sky and it's easily visible from both the northern and southern hemisphere. In the northern hemisphere
we will see it in our summer months, but if you live in the southern hemisphere that's during
the winter time, remember the seasons are opposite, and Antares which I circled right here, you can see
this whole constellation of scorpius is estimated to be 550 light years away and it's actually a
binary star system. There is a red supergiant and a blue main sequence star that sometimes can be seen
in certain celestial events. It is thought that the name Antares comes from the ancient greek phrase
meaning rival of mars, anti-meaning against, and ares meaning Mars. This is probably due to its
mars-like appearance in both color and brightness, and I have seen both Antares and Mars together in
the sky and it's true they really do look alike, and keep in mind that Antares is very close
to the ecliptic, which is the path of the sun, so it should be easily seen in both the northern and
southern hemisphere, and Antares is a very popular target for astrophotographers and this is because
Antares illuminates surrounding gas and dust in the Rho Ophiuchi Cloud Complex, sometimes that's
called the Antares Nebula and I have a whole video about this because it's super fascinating to me,
so be sure to go see that video where I explain what's going on here in detail. To give you a brief
overview, the Rho Ophiuchi Cloud Complex is both an emission, reflection, and absorption nebula,
right here, and it's estimated to be 420 light years away. So if we were to zoom in on this
square what exactly are we looking at? Well here is where Antares is and it's illuminating
all this gas and dust that is in front of this star system, from our perspective, but there's also
two globular clusters here, there's a star right there, and also another star. So this is just a
really awesome area to look at and photograph if you are into astrophotography, and you can see this
on the star map too. Here's Antares, and here are those two globular clusters I pointed out earlier.
Now let's dive into the specifics of this binary star system. So if we were to zoom into
that particular area this is what the Antares system is estimated to be like. Antares A is a
red supergiant star towards the end of its life and Antares B is a main sequence blue giant star.
So let's get into the details, Antares A, which is represented here in this artist's impression,
is estimated to be 550 light years away and it's classified as a M1 star. It's a red supergiant star
and it's estimated to have 11 to 14 times the mass of our own sun, and 680 solar radii, and it's 10,000
times more luminous than our own sun. So this is just incredible to think about how large and and
how large a star is yet it's relatively cool when we compare it to the sun, its temperature range is
3,600 kelvin, that's the reason for its colors. So remember cooler stars
tend to be in the red zone, red color whereas hotter stars tend to be blue.
This system is estimated to be 15 million years old, so much younger than our own system
and it's the brightest of the binary pair and it's a variable star, so
its magnitude can change over the course of time. Now looking at Antares B, this is classified as a
B2 star, which is a blue giant star. It's bluish white in color and also the same distance away.
It is much larger than our own Sun. It's estimated to have seven solar masses and five solar radii
and it's 2,756 times more luminous than the Sun and it's much hotter than our own Sun at 18,500
degrees kelvin and these two are separated by 529 astronomical units,
and remember I mentioned that it's, it's very bright in the sky, so that makes it easy to find
even if you have areas with high light pollution, and here we go Antares takes the 15th spot
and just to give you an impression and really impress upon you how large this star is this is
a diagram I found of Antares A, which again it's classified as a super giant star that is expected
to become a supernova, it has enough mass to do so, and this what this diagram is showing you is that
the surface well not so much the surface but the atmosphere, which is what the chromosphere and this
area is, it is larger than the orbit of Saturn. So it is it's just such a huge star, and that's hard
to even conceptualize. Here's another diagram I saw or I found for size comparison. If this
little pixel were the sun this right here would be Antares, this really huge one. So that shows you
it's it's larger than the orbit of Mars and then of course its atmosphere would extend even past
the orbit of Saturn as we saw, and if we were to stick these stars onto the hr diagram, which is how
scientists classify temperature color at magnitude and luminosity, here is where the Sun is. The Sun
is a G2 star and we measure luminosity based upon our own sun. So here is one solar,
one Sun as luminosity, but if we were to find where Antares is, well Antares A is right here, It's an M1
star so it should be right in that arena, and and you notice it's cooler but it's also larger. It has
more surface area that's why it's brighter, and this is where Antares B would be. It's a B2 star
and its temperature is around 18,500. Some other cool things about Antares is that its surface was
mapped by the European Space Observatory's very large telescope, Inferometer, and this hasn't really
been done for many other stars besides our own Sun. So this just shows you that this huge, almost looks
like two eyes doesn't it staring right at us but um, this is just really interesting to learn about
you know how scientists study stars and you know this is this is one I'm sure I could go on and on
about this particular star. It's just it's so easy to find in the sky, and it is really pretty and as
as I was learning more about it I was, it's neat to find out that when we're actually looking at this
star it's it's two stars. It's a binary star system like many stars out there. Here's another view,
this is Scorpius right here and this is Antares. So in the next portion of our video we're gonna
get into the specifics of exactly where you can point your telescope at to look at this star
and some techniques with how to find it in the sky. In the last portion of this video we'll go
over some strategies you can use to find Antares in the sky. For me it's one that's really easy to
find because it's bright, you simply look south, look for the bright red star and it usually is
Antares and if it's not Antares it might be Mars. You can figure that out by just watching the sky
over the series of different nights so you can see the motion of the planets versus the stars, and as
you're looking at this diagram my eye is instantly drawn to the shape of Scorpius. So even just
finding the star pattern makes it easy enough to find this bright red star and I really like this
picture overall because it shows the summer sky in the northern hemisphere in its entirety. So some
things to point out, we have the Summer Triangle asterism, I have a whole video on that so if you
want to learn more go see that video, and then you can also see the Milky Way, which is brightest
in the summer months in the northern hemisphere, and if we were to point everything out here, this
is where Scorpius is, here is where Antares is, this is Libra, we have Sagittarius, and then Ophiuchus
takes up a large portion of the sky. So I've got videos on all these constellations if you want to
learn more go see those videos, and then the three constellations that make up the Summer Triangle
asterism include Lyra, Cygnus, and Aquila, and if you wanted to go over like specifics, exactly where it
is in the sky with celestial coordinates we can do that as well. Before we do that I just want to
bounce back here as well if if you want to see the the comparison of Antares with a planet, this is it
right here. You can see that Antares can be just as bright as a planet. I am gonna guess this is
Jupiter simply because it's not reddish in color like Mars would be, but Mars and Jupiter are very
similar in magnitude. So when we are looking at Scorpius, it's celestial and coordinates are listed
right here for right ascension and declination. As you notice, notice the blue line that goes
through this star map, this is called the ecliptic and this is the path of the moon the sun
and the planets as they go around in the solar system, and how we view them from our perspective.
So I have a whole video about right ascension and declination so iIll link that in the information
below, but just as a quick review right ascension measures the east-west coordinates of the
sky, the celestial sphere. We can kind of equate it to longitude using earth coordinates and we
measure that in hours, minutes, and seconds, where declination measures north south coordinates, and
we can kind of equate that to latitude in terms of earth coordinates and we measure declination
using degrees, arc minutes, and arc seconds. So if you want to know know more about that system
please go ahead and see that video. So I hope this video was helpful for you to learn
a little bit more about the gorgeous star known as Antares. It's very easy to point out,
right here in the sky, and it's bright red and you just need to look to the south, but when you do
now you know that there is there are actually two stars here. You have Antares A and Antares
B. Antares A is the larger one, it's a red super giant star that'll eventually become supernova, and
Antares B is a blue giant star. It's on the main sequence which means it's in a stable pattern and
a star spends 90 percent of its life in that phase and they're separated by 529 astronomical units. So
thank you so much for watching I hope you love the star Antares as much as I do, it's definitely as I
said many times Scorpius is one of my favorite constellations, I just it's so beautiful in the
sky and Antares is one that is easy to find . So I wish you luck and as always keep looking up.