Welcome to Learn the Sky. We release new videos every Tuesday, where we will be exploring the sky
one constellation at a time. If you are new to this channel hit the subscribe button and click
the bell to get notifications about new videos. Learn the Sky is also on Patreon, so if you'd like
to support this channel visit the patreon link listed below, and finally if you would like to
study the sky in greater detail and need a guide visit learnthesky.com to learn about free lessons
we offer and classes released each season. The constellation of Ophiuchus, which is represented
as a serpent bear contains a fascinating star called Barnard's star. It has a magnitude of 9.5,
which renders it invisible to the unaided eye, but in the past 100 years scientists
have collected fascinating data about this star and have even discovered evidence of an exoplanet.
Barnard's star is one of the most studied red dwarfs because of its proximity to Earth.
It's also famous for how fast it moves in the sky. Its prosper motion classifies it as the fastest
moving star in the sky that has been observed thus far. Its motion is so fast it has been nicknamed as
the runaway star. Before we look at the speed of the star let's take a look at some of its
properties. Barnard's star is a low mass red dwarf star, and it's estimated to be six light years
away from Earth. It's the fourth nearest star to the sun and the second closest red dwarf star.
To give you an idea of its size, here is a picture of the Sun, here's a picture of Barnard's star and
then here is a picture of Jupiter in terms of its size. So it's close in size to Jupiter instead
of the Sun, and what's interesting about this star is that it was named after the American astronomer
E. E. Barnard. He was not the first to observe the star, but in 1916 he measured its proper motion
and realized that at 10.3 arc seconds per year it was moving and this is the highest known proper
motion for any star. If we take a look at some of the Sun's closest neighbors, here we have the Sun,
this is where the oort cloud is, where comets originate from. So at two light years and then
four light years we have the Alpha Centauri system. It's not pictured here but it is in fact a three
star system. So Alpha Centauri and its companion, and then Proximus Atari is another red dwarf star.
Proxima Centauri is the red dwarf that's closest to us.
Next at six light years we have Barnard's star, and when we're talking about its proper motion
this is what I mean. This is Barnard's star showing its position relative the stars every five years
from 1985 to 2005. So this is showing us that this is the fastest moving star in
the night sky. We wouldn't be able to observe it because Barnard's star only has a magnitude of 9.5.
So you definitely would need magnification in order to see it.
In November of 2018 an international team of astronomers including the European Southern
Observatory and Carnegie Institution for Science confirmed that an exoplanet is orbiting around
Barnard's star. It was named Barnard's star Planet B, and it lies within the system snow line, which
is an ideal spot for ice to accumulate. Planet B orbits the star every 233 days, and is estimated
to be 3.2 times the size of our own Earth, which would classify it in the super earth category
of exoplanets. This planet is most likely very cold and outside of the proposed habitable zone,
and it's known as the second closest exoplanet to our own solar system.
Even though Barnard's star is a red dwarf and it only has a magnitude of 9.5, thus make it invisible
to our own unaided eye, it still has captured the imagination of many science fiction authors ,
filmmakers, and game developers. So if you've heard of Barnard's star before it could because could be
because you've read about it in a science fiction book, or explored it in a video game. Here are some
fast facts about Barnard's star. Barnard's star is not moving in the general direction that most of
the other stars in the Milky Way are traveling. It is simply traveling through the local neighborhood
and this is what accounts for its fast movement through the sky. If Barnard's star replaced our own
Sun it would only be 100 times brighter than our moon, and it would not be able to support life on
Earth. In fact it would take the mass of seven of Barnard's stars to equal the mass of our own Sun.
Ancient civilizations were unaware of this star because it cannot be seen with the unaided eye,
it was only discovered a little over 100 years ago. Even though you may not be able to see this
star without the help of a telescope or a pair of binoculars it's still fascinating to know
that this star is located within the boundaries of Ophiuchus, and if you do have a telescope I
encourage you to try to find this tiny, small star that's only six light years away and moves so fast
in the sky its nickname as the runaway star. Thanks for watching and keep looking up!