What is Rigel and Why is It so Bright?
Rigel is the brightest star in its constellation Orion, along with Betelgeuse and 81 other stars!
We all got super excited a few years ago when Betelgeuse was speculated to die and
explode into a supernova. Unfortunately that didn’t happen and the star was just “sneezing”.
Bless you Betelgeuse, thank you for the false alarm. We understand, you’re a really really
cold star. But enough about you, we are curious to meet your incredibly bright blue neighbor, Rigel.
Let’s take a look on why Rigel is so bright, and why some people swear they’ve seen it
dimmer than usual. Those people aren’t wrong, Rigel does change brightness!
But before you start watching this video, let me know in the comments whether you have ever
been able to spot Orion on your own or not. Well, for those of you who weren’t able to,
take an imaginary pen and draw this little picture in your mind: three consecutive vertical dots and
two dots symmetrical along the axis of the dots you just drew. Those are the Orion’s
brightest stars that you can distinguish if you pay attention at the night sky.
Orion is mostly visible in winter, so take a look tonight and see if you can spot it.
It will be easy to find, since it's the most recognizable constellation during the night.
The bright blue-ish star that you see on the left side of the constellation is the
famous Rigel, opposing the supergiant red star Betelgeuse that is on the right side of Orion.
Take a few moments to appreciate the vastness and beauty of the night sky and Orion's bright stars.
And if you feel like a bit of adventure, why not try to look for some of the other constellations
like the Big Dipper and the Pleiades (better known as the Seven Sisters)? Who knows,
you may even find a shooting star or two! But this video is about Rigel, so let’s not
waste so much time and get into it! ---
So where exactly is Rigel located in the universe?
Rigel is located in the lower left corner of the constellation's prominent figure,
the Hunter, and is even the easternmost star in the famous asterism known as the Winter Hexagon,
making it a favorite amongst stargazers. Rigel has long been associated with the legend of Orion,
a giant hunter in Greek mythology, and was first catalogued by the ancient Babylonians as “the Star
of the Giant” or “the Star on the Left Foot of the Giant, and its name comes from the Arabic word
'Rijl Jauzah al Yusrā’, meaning 'the left leg of the giant'. No matter where you are on the planet,
if you look up to the night sky you will be able to spot Rigel without the aid of optics.
Its brilliant blue coloring and position as the brightest star in one of the most well-known
constellations make it easily identifiable. And even if you can't spot it with the naked eye,
it is still a beautiful sight to witness through a good set of binoculars or a telescope.
It is around 863 light-years away from Earth. And I know it can be hard to wrap our minds
around astronomical distances in scope, it’s only human. So to put it into perspective,
light from our closest star, the sun, takes a mere 8 minutes and 20 seconds to reach us. In contrast,
the blue light we observe twinkling in the night sky has taken over 8 centuries to reach us! The
light you see at this moment is light that’s been traveling since the 13th century. That’s like two
centuries before Christoph Columbus discovered America! Feels like a long time ago, no?
What makes this star so special, and so bright at times but so dim at others?
Rigel, and in a more scientific context also known as Beta Orionis , is a supergiant star located in
the constellation Orion. It is the brightest star in Orion, and one of the brightest stars in the
night sky. Rigel is from 61,500 to 350,000 times brighter than our Sun and can be seen from all
over the world. Its exact brightness is hard to measure as its distance and luminosity is
uncertain. That is due to the fact that Rigel is an intrinsically variable star. A star is
classified as a variable star if its brightness, when viewed from Earth, fluctuates over time.
This occurs when the star alternates between periods of dimness and brightness.
However, you can't miss this star in the night sky due to its striking blue hue,
standing out among other stars that are usually yellow, orange, or red.
Although it is often the case, Rigel is not always the brightest star in the Orion constellation.
Betelgeuse, the huge red supergiant, sometimes shines brighter in comparison.
Rigel's luminosity is affected by its unique characteristics. Although only
10 million years old, much younger than our own nearby star, its massiveness has caused
it to deplete its hydrogen fuel source earlier than expected. Rigel will eventually move on
to burning helium, oxygen, and silicon just like other supergiants and will eventually
reach its death in the form of a supernova. The star is believed to have formed around 8
million years ago. Astronomers at the University of Washington have used data from the Hubble Space
Telescope to measure the amount of ultraviolet radiation Rigel is giving off, and from that,
they calculated the star's age. According to the team, Rigel is 8.2 million years old, much younger
than the 12 million years that astronomers have believed for years. The new age calculation has
implications for Rigel's future. The star is only halfway through the life cycle that stars in its
class usually get before they explode into a supernova. Supernovas are incredibly powerful
stellar explosions that occur when a star runs out of fuel and can no longer generate enough energy
to fight off the gravitational attraction of its own mass. They are some of the most energetic
events in the universe, releasing more energy than the Sun will generate over its entire lifetime.
This is bad news for any planets that may be orbiting Rigel as they will be destroyed in
the explosion. Of course, this is assuming that any such planets exist, which is still unknown.
Astronomers would have to spend more time observing Rigel to determine if there are
any other planets in its system that could be affected by the star's demise.
In the end, Rigel may have a shorter-than-expected lifespan, but it will still be shining down on us
when the time comes for it to become a supernova. It is predicted that when Rigel goes out,
it will be so bright that it will be like having a second moon in the sky. For now,
we can just admire its beauty in the night sky and appreciate its life span, however short it may be.
The supergiant star takes its blue hue from the spectral type B8 Ia that it belongs to.
The dust surrounding Rigel appears blue due to its intense blue starlight, as well as its
ability to scatter blue light more effectively than red. But why are Betelgeuse and Rigel such
opposites in color? Stars of different colors have distinct surface temperatures, resulting
in them emitting different colors of light. Hot stars emit a shorter wavelength of light, which
appears blue or blue-white, while cool stars emit a longer wavelength of light, which appears red.
Why the comparison with Rigel’s neighbor Betelgeuse? Nobody likes to be compared.
But scientists believe that Rigel will look a lot like its friend Betelgeuse, the red-hued "armpit"
of the giant, in a few million years. Let’s take a quick look on what Betelgeuse really is.
It is a much cooler star than Rigel, yet still much brighter than our Sun. It is an irregular
pulsating supergiant star, nearing the end of its life, which expands and contracts in size
spasmodically, ranging between 550 to 920 times the diameter of our sun. This would mean that
at its maximum size, if placed at the center of our solar system, it would engulf Mercury,
Venus, Earth, Mars, and Jupiter! Henry Neeley, a lecturer at New York's Hayden Planetarium,
described Betelgeuse 75 years ago as "like an old man with his strength almost entirely spent,
panting in the asthmatic decrepitude of old age." Putting the spotlight back on our star (not that
it needs any), Rigel’s mass is estimated to be around 21 times that of our Sun. It is around 79
times the size of our Sun in terms of radius, and has an approximate surface temperature of 5810 K.
Rigel is a true giant compared to our Sun, to put it in perspective, 1.3 million
Earth-sized planets could fit inside of it. One of the most important aspects of Rigel is
that it serves as an important reference star for astronomy. It was used to measure and calibrate
the brightness of other stars, which can then be converted into their apparent magnitudes.
Rigel is also an interesting astronomical object in terms of its age and size, as it is located
at a remarkable distance from Earth and is one of the brightest stars in the night sky.
As such, it serves as an important reference point in many astronomical observations and studies.
Aside from its astronomical significance, Rigel has deep and ancient cultural and
mythological significance. In ancient cultures, Rigel was often associated with rain and floods
due to its position in the night sky. In some stories, it was even seen as a symbol of hope,
as the star would shine brighter in the winter months when darkness loomed heavily.
Fun fact that I am sure only you, space enthusiasts, know: Rigel is actually a
multiple star system, consisting of three stars orbiting a common center of mass. The brightness
of Rigel A, the main visible supergiant, overshadows the other stars in this multiple star
system. Rigel Ba, Rigel Bb, and Rigel C are much smaller and form their own triple star system.
Despite its dazzling brightness, Rigel is not the brightest star in the night sky. That
honor belongs to Sirius, which is located in the constellation Canis Major. Sirius is estimated to
be about twice as bright as Rigel, making it the most luminous star to be visible in the night sky.
In comparison to other stars in the universe, Rigel is still incredibly bright. It is estimated
to be thousands of times brighter than most stars, placing it among the top ten brightest
stars in the night sky. This makes it an ideal star to look out for when viewing the night sky.
We have reached the end of our journey through the night sky. We have seen why
Rigel is so bright and why it is considered to be one of the brightest stars in the sky.
It is a supergiant star of immense size with a stunning blue hue,
and it is a multiple star system that serves as an important reference point in astronomy.
We’ve seen how its unique characteristics, such as its position in the night sky and its current age,
affect its luminosity. And we have explored its ancient mythological and cultural significance.
You've reached the end of this video! Leave a comment and tell us what you like to see most
in the night sky! We are interested in what you think! Thank you for watching! See you later.