When looking up into the night sky, thousands of
stars shine light from hundreds of light years away. Ancient astronomers
created shapes in the sky out of these stars so that they would be able
to locate them night after night. These shapes are known as constellations.
In this way, ancient cultures were able to observe the paths of these celestial
shapes through the sky for hundreds of years. Along with these constellations
came myths explaining how or why the shapes were put in the night sky.
Ancient cultures across the globe connected the dots of the constellations
differently, but two constellations that have been seen the same in multiple
cultures are Leo and Orion.
On a clear winter evening there are seven bright
stars that stand out among all the others. These stars comprise the
constellation Orion, most well known as the Hunter in Greek myths.
The Greeks were not the only ancient civilization to see this group of
stars as a constellation, however. The Egyptians had beliefs as to
whose soul was up in the sky. In modern times, there have been many
studies done on Orion’s stars because of a Nebula in Orion’s Sword that
seems to be the birthplace of hundreds of thousands of stars. Among
these are six of the seven brightest stars in Orion. In this way,
Orion is a young constellation full of keys to discovering some unknown
facts about the early stages of stars.
The ancient Egyptians were a polytheistic culture
that believed that their ruler, or pharaoh, was the son of Osiris, God
of the Dead, and his wife/sister Isis. In the legend of Osiris, he
became king of Egypt and ruled with his sister. However, Osiris had
a jealous brother, Seth, who killed Osiris and cut up his body into pieces
before Osiris had an heir to assume the throne. Isis found all of
the pieces of Osiris and put him back together by using her special healing
powers and mummified him in order to bring him back to life. Osiris
did not stay alive for very long, but long enough for Isis to become pregnant.
She hid from Seth and gave birth to a son, Horus, who ended up taking the
throne from Seth and became the first pharaoh. Meanwhile, Osiris
had changed himself into the constellation Orion, and ruled the Duat, or
the Heavenly Kingdom of the Dead (Bauval, 92-94). From this story,
we know that the constellation Orion was to the Egyptians the soul of Osiris,
called Sahu. Dr. Otto Neugebauer and Dr. Richard Parker were the
first to give solid proof that the ancient Egyptian’s constellation of
Sahu was the same as our constellation of Orion. Sahu was important
to the ancient Egyptians because they believed that the souls of the dead
pharaohs became stars and that, more specifically, they became stars within
Sahu. This is because Osiris rules the Kingdom of the Dead, and since
his soul is Sahu, it would make sense that the Kingdom would be near Sahu
(Bauval, 87-89).
There has also been much speculation about how the
pyramids themselves relate to Orion. In the sides of the Great Pyramid
of Giza are shafts that for years were assumed to be airshafts from when
the Egyptians were building the pyramid. However, with the recent
research and focus on the ancient Egyptian’s astronomy, another theory
has been brought forward. Dr. Alexander Badawy, an Egyptologist,
hypothesized that the shafts were windows to the stars. Badawy asked
for the aid of an astronomer, Virginia Trimble, in 1964 to calculate the
necessary formulas that would tell them what stars would have been visible
through a shaft in the King’s Chamber in about 2600 BC. Her calculations
showed that the three stars in Orion’s Belt would have been at the correct
declination to have been visible though the shaft. Trimble also calculated
the declination for other bright stars in the southern sky and proved that
no other significant stars would have been visible through the shaft.
This is strong evidence that the shafts were built as a way for the pharaoh’s
soul to exit the pyramid and be on a direct route to becoming a star in
Sahu (Bauval, 99-103).
Modern scientists have their own myths and stories
about the constellation Orion, except most of these deal with math and
numbers rather than gods. Another difference between the ancient
and modern astronomers is that ancient astronomers studied the constellation
as a whole, like what time of the year the constellation was visible while
modern astronomers focus on the individual stars in the constellation.
The seven brightest, easiest stars to see in Orion are (in order of appearance):
Bellatrix; Betelgeuse; Mintaka; Alnilam; Alnitak; Rigel; and Saiph.
With modern equipment and knowledge (i.e. formulas), astronomers are able
to estimate quite a bit of information about these far away stars.
Bellatrix (beh-LAY-trix)
Bellatrix, Latin for “female warrior” is the first
star in Orion to rise and its Arabian name actually means “the leader.”
Bellatrix, or g Orionis, is a blue-white B2
giant III with an apparent magnitude of 1.6 and an absolute magnitude of
-3.3. It is about 300 light years from earth with a luminosity that
is 1800 times our sun and a surface temperature of 23,000 0K
(Beyer, 330-331).
Betelgeuse (BET-el-jooz)
To me, Betelgeuse, Arab for “Armpit of Orion”, is
the most interesting star in Orion. It is believed that it is actually
falsely named. When translating the Arab, a B was used instead of
a Y, and so the name of the star has come to mean “Armpit” instead of “Hand
of the Central One.” Betelgeuse, or a
Orionis, is the one of two red supergiants visible in the Northern Hemisphere;
the other is in the Scorpion. However, specifics about this star
vary because Betelgeuse is a variable star. That is actually the
reason it was wrongfully called the alpha star, even though Rigel is the
brightest star in Orion. Back in 1836, John Herschel was the first
to call Betelgeuse a variable star. He noticed that it became the
brightest in 1936, 1840, and 1852. Betelgeuse’s lowest recorded apparent
magnitude was 0.2 in 1933 and also in 1942 although it usually ranges from
0.4 to 1.3 within a period of 6.4 years. This change in magnitude
is equal to a 200% change in brightness. Betelgeuse is a yellow-orange
M2 supergiant Ia-Iab that lies about 650 light years from earth.
It has an estimated surface temperature of 3,400 0K with an
absolute magnitude of -5.7 and its mass varies from 10 to 15 times that
of our sun. It is usually the 17th brightest star in the sky and
is estimated to be about 4-10 million years old which, as far as we know,
means it is nearing the end of its life and could go supernovae soon.
The diameter change of Betelgeuse is what causes its luminosity to vary.
The range of its diameter change is 700 to 1,000 times our sun’s diameter
and at its maximum diameter, if Betelgeuse were placed where our sun is,
the star would reach beyond Jupiter’s orbit (Beyer, 342-343).
Mintaka (min-TAK-ah)
Mintaka, Arab for “Belt of the Central One”, is
the western most star (the star furthest to the right) in Orion’s belt.
Mintaka, or d Orionis, is a blue white B0 giant
III with an apparent magnitude of 2.2 and an absolute magnitude of -4.4.
It lies about 800 light years away with a luminosity about 50,000 times
greater then our sun with a surface temperature around 28,000 0K
(Beyer, 344-345).
Alnilam (al-HIGH-lam)
Alnilam, from Arab description “String of Pearls”,
is the middle star in Orion’s Belt. Alnilam, or e
Orionis,
is a blue-white B0 supergiant Ia that is about 1,600 light years from earth.
It has an apparent magnitude of 1.7 with an absolute magnitude of -6.7.
The surface temperature is estimated at 28,000
0K with a luminosity
40,000 times greater then our sun (Beyer, 346-347).
Alnitak (al-nih-TAK)
Alnitak, another Arabic word for “Belt”, is the
last star in Orion’s Belt to rise (the eastern most or left-most star in
Orion’s Belt). Alnitak, or z Orionis,
is actually a close triple star system. The primary star is a blue-white
09.5 supergiant Ib with an apparent magnitude of 1.8 and an absolute magnitude
of -6.4. This star is 30,000 time more luminous than the sun with
a surface temperature around 29,500 0K. It is about 1,500
light-years from us and about 18 times more massive than the sun.
The secondary star in the system is 2.4 arcsec from the primary star.
This star is blue-white with an apparent magnitude of 4.2 and a mass of
six times the sun. The third star in the system is not necessarily
gravitationally bound to the system. Not much is known yet about
this star due to lack of observation, but it is 58 arcsec from the primary
star (Beyer, 350-351).
Rigel (RYE-jel)
Rigel, Arab for “Left Foot of Orion”, is the brightest
star in Orion. Rigel has kept the same name since the 10th century,
which is a very rare occurrence. Rigel, or b
Orionis, is the 5th brightest star in the sky with an apparent magnitude
of 0.1 and an absolute magnitude of -7.0. It is a blue-white B8 supergiant
Ia that is 55,000 times brighter then our sun with a surface temperature
of 10,100 0K. Rigel is about 800 light years away, but
if it were as close as Sirius (about 8.6 light years) it would shine 150
times brighter then Venus. Even though this star is said to be the
brightest star in Orion, it always looked dimmer than Betelgeuse to me.
The reason I think this is so is because whenever I observed Rigel, it
was close to the horizon and so I was seeing it through light pollution
which would make it seem dimmer (Beyer, 352-353).
Saiph (SAFE)
Saiph is the last star in Orion to rise and marks
the right knee of the giant. Saiph, or k Orionis,
is a blue-white B0.5 supergiant Ia with an apparent magnitude of 2.1 and
an absolute magnitude of -6.8. This star is the farthest away of
the main stars in Orion at 2,000 light years with a luminosity about 45,000
times our sun and a surface temperature of around
27,000 0K. Scientists have measured Saiph to be moving
21 km/s away from the earth probably due to an ejection from its cloud
of birth (Beyer, 362-363).
The Orion Nebula
When Gina and I observed Orion, we looked at both
Betelgeuse and Rigel though binoculars and telescopes, but all that happened
was we saw larger dots of light. The really interesting phenomenon
to find in Orion is truly the Orion Nebula. The cloud of gas about
1,600 light years from earth is the birthplace of thousands of stars.
In fact, of the stars I mentioned, Betelgeuse is the only star not in the
Orion B1 Association. This Association is all young, hot, blue-white
stars that scientists believe were made by the Orion Nebula. The
Nebula itself is about 30 light years in diameter and is faintly visible
to the naked eye, if you know where to look. The Nebula is located
below Orion’s Belt, almost in between Alnilam and Alnitak. It merely
looks like a fuzzy spot and binoculars don’t make it much clearer, but
when looking through a telescope the Nebula is much easier to pick out
and view (Beyer, 355-357).
This is a quick overview of what scientists of our
era and those of centuries ago have discovered about the constellation
Orion. However, the constellation Leo, like Orion has many astronomical
spectaculars! In this section, the stars of Leo and their specifics
will be discussed as well as ancient Egyptian cosmological understanding.
One can locate the constellation Leo, the lion,
easily by looking in the night sky in the early spring and summer months
and finding a group of stars that resemble a backward question mark.
This configuration of stars is otherwise known as the “sickle” and if you
look to the left of this sickle, a group of three visible stars form a
triangle. Together, the sickle and triangle asterisms form the head,
mane, heart and tail of the lion. This constellation definitely resembles
a lion prancing across the night sky!
Although it may seem silly to compare a group of
stars to an image of a lion, the constellation Leo is in fact much more
than it appears! Leo is a vast space within our universe filled with a
variety of astronomical phenomenons. Such events as double stars,
binary systems, spiral and elliptical galaxies are all simultaneously occurring
when we, as observers on Earth, look ‘above’ and see this lion.
What exactly is the Constellation Leo?
Leo is comprised of over one hundred and sixty stars,
although only about ten are visible to the naked eye. Of these stars,
Regulus, alpha Leonis, (or the little king), is the brightest, with
an apparent 1.4 magnitude and an absolute magnitude of –0.6. It is a main
sequence star. Regulus is located at the very bottom of the sickle and
also happens to be the closest 1st-magnitude star to the ecliptic.
The late Copernicus gave the name Regulus to this star. It is an
estimated 90 light years away from Earth and has luminosity 110 times that
of the Sun (Rao 2, p68)! As our research revealed, Regulus is actually
a double star! There is a much dimmer, 7.9-magnitude star orbiting
the 1st-magnitude star. Seeing Regulus as a double star
is impossible with the naked eye because the 1st-magnitude star
is so bright that it outshines the dimmer one.
Above Regulus, the star Algieba, gamma Leonis,
(the lion’s mane) can be found. This star is also a binary system,
located about 85 light years away from Earth. The brighter of the
two is an orange-red giant with an apparent 2.2 magnitude and an absolute
–0.4 magnitude. The other star is a yellow giant with a magnitude
of about 4. The two stars in Algieba are “separated by a distance
three times that of the distance between Earth and Pluto” (Berman 2, p81).
The next brightest star found in Leo, aside from
Regulus, is Denebola, beta Leonis (or the lion’s tail). It has an
apparent magnitude of 2.1 and an absolute magnitude of 1.6. It is 40 light
years away and 22 times as luminous as the sun (MacRobert, p 57). Denebola
is a main sequence star. Denebola is located at the very far west
of the constellation in the triangle asterism. Denebola is a blue-white
star with a surface temperature of 8,900 degrees Kelvin. Denebola
is also a double star with a companion of 16th magnitude. (Beyer, p115)
The star Zozma, delta Leonis (or the lion’s
back), is located in the sickle and is an approximately 80 light years
away from Earth. It has an apparent magnitude of 2.6 and an absolute
magnitude of 0.7. It is 50 times more luminous than the sun and is
a main sequence star.
The triangle asterism in Leo contains what is known
as the Leo Triplet. These are “M65, M66 and NGC 3628 and are all
spiral galaxies and lie 22 million light years away and are bound up in
each other’s gravitational grip” (Sky & Telescope p26).
These details on Regulus, Algieba, Denebola and
the Leo Triplet all confirm that within the Constellation Leo there are
an abundance of astronomical events occurring. There are also many
other dimmer double stars and binary systems within Leo. For example,
tau
Leonis is a double star with one star at 5th magnitude and the other
at 7th magnitude. The binary system of omega Leonis is very interesting,
the two stars revolve around each other with an orbital period of 117 years!
Other doubles include 88 Leonis, 83 Leonis, 90 Leonis, sigma 1521, Osigma
215, 81 Leonis, sigma 1399, sigma 1421 and sigma 1442. (Haas,
Sissy and MacRobert p 77-8)
There are also other galaxies within Leo other than
M65, M66 and NGC 3628. Both M95 and M96 are spiral galaxies and M105
is an elliptical galaxy! All the galaxies within Leo are undetectable
to the naked eye. They look just like points of light in the sky,
as do the other double stars and binary systems!
Ancient Egyptians Recognize Leo
Looking at the night sky is a beautiful experience.
Thousands of stars are visible as specks a blinking color. Some stars
seem to fall randomly in the sky while others appear to have a very definite,
familiar shape. The constellation Leo is often referred to as a lion.
The stars are arranged in such a way that from the view on Earth they actually
do resemble a very large lion. Leo is actually part of the zodiac, or the
path of the moon through its revolution around Earth. Leo has been
seen as a lion for centuries. One culture in particular that paid
special attention to Leo was the ancient Egyptians.
The ancient Egyptians made accounts for their observations
of Leo. For one, Leo was very close to the zenith of the sky in Egypt
around the summer solstice between the dates of 2000 BC to 1 BC.
This is a good indication as to why the Egyptians greatly connected Leo
with the arrival of summer.
Ancient Egypt was an agricultural community.
They greatly depended on the irrigation of the Nile into their farmland
to grow crops. Because they greatly subsisted on farming this crucial
role of irrigation was necessary. Once a year the Nile would flood.
When this happened, the soil in the surrounding areas became very well
nourished. This fertile soil made the farming that supported their
life and civilization possible. At the time right before the flood,
Leo was very close to the zenith of the sky. In ancient times they
believed that Leo’s purpose was to announce this flood. For this
reason the constellation Leo was admired and respected. It is also
suspected that the lions in Egypt migrated to the banks of the Nile during
the hot summer months to gain relief from the intense heat. This
migration, which coincided with the constellation being overhead, was a
very significant event.
Another indication of the lion’s importance in Egyptian
culture is that the sphinx was composed of the body of a lion and the head
of a man. The sphinx guarded the pyramids, which were the tombs of the
pharaohs, who were believed to become gods in their after lives.
The lion must have been greatly feared and respected to be placed in such
an admirable position.
In 1799, one of Napoleon’s officers discovered a
sandstone medallion on the Temple of Isis at Dendera. This sandstone
medallion dates back to the 1st century BC and contains pictures
of the zodiac, including one of the lion. The ancient Egyptians believed
that after death, pharaohs went up to the sky to sleep with the gods.
By putting the zodiac on this temple, one can assume that the zodiacal
constellations were very significant to one’s after life as well as life
on Earth.
Studying the cosmology of the ancient Egyptians
has revealed that the shapes, today known as constellations, were, in ancient
times, explanations for the events that governed their society, like the
flooding of the Nile. Today, much more is known about the composition
of the constellation Leo. It is fascinating to compare those beliefs
of ancient times with our modern understanding. This comparison can
only make one wonder what will be discovered and understood in the coming
centuries…
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