English 12
Famous Stars in our Galaxy There are about 300 billion different stars in our galaxy. All of which contain different history, characteristics and general information. They each contain their own story of how they came about. Many of these stars are a part of a certain constellation and have been around for billions of years. Polaris is one the best known stars. (“How Do Stars Form,” n.d.) This star is known by many names like the North or Pole Star. Polaris has not always been the North Star and will not always remain the North Star. As centuries change the North Star will also do so. “A famous star called Thuban, in the constellation Draco the Dragon, was the North Star when the Egyptians built the pyramids.” (earthsky) Polaris will remain as the North Star for many more centuries to come. There was a time where people depended on their lives on this star to guide them. Fortunately, they used the North Star and the Big Dipper without getting lost. “. When slavery existed in the United States, slaves counted on the Big Dipper (which they called the Drinking Gourd) to show them the North Star, lighting their way to the free states and Canada.” (earthsky) Polaris is not hard to miss in the sky; it is the 50th brightest star and does not disappear. The reason this star will not disappear is due to the fact that the Earth’s axis is aligned pointing towards Polaris in the same direction North faces but will eventually shift over time. In comparison to the sun, this star is 10,000 times brighter, 100 times larger and has 10 times more mass to our sun. Polaris has about the same temperature as the sun. (glyphweb) Sirius also known as The Dog Star or Canicula was discovered in 1915. Sirius gets its name from the use in the Greek calendar. “The time of year when this star rose and set with the Sun was the hottest part of the summer, and was given the name Seirios, 'scorching', a name that was acquired by the star itself”. This star played a significant role to the Egyptian agricultural course due to it rising with the annual flooding of the Nile. It made such a big impact that they gave it its own goddess, Sopdet or also known as Sothis. This star is located in the constellation of the Canis Major. “Sirius is the fifth closest star to the solar system”. (Sirius’s Connection to Human History)It is only 8.6 light years from our solar system which makes this star the brightest star known. Sirius has a binary system which means that there are two stars revolving around each other. “Sirius A is a blue-white star 25.4 times bigger than the sun. Its surface temperature is twice as hot as the sun, over 20 times brighter, and it’s mass 2.32 times more.” (Sirius’s Connection to Human History) Sirius B revolves around Sirius A. This star is the first white dwarf to be discovered. Its diameter is almost equal to that of the earths. “It has a mass is 98% that of the sun, making it extremely dense.” (Sirius’s Connection to Human History) Another famous star is Betelgeuse. This star gets its name from the Arabic meaning “Armpit of the Central one”. It is the tenth brightest star in our galaxy and the brightest star in Orion which is the constellation in which it lies in. This star shines an orange-red color, 7,500 times brighter than the sun. Its surface temperature is 6000F. Betelgeuse is one of the largest stars known with a diameter of 700 million miles. (nrao) This star is 520 light years away and also has about five companion stars in its orbit which is rare for a Red Super Giant. “Red super giants are stars that are close to the end of their life”. (nrao) Betelgeuse has about ten years left till it ends in a supernova explosion. Vega is one of the 300 billion stars best known in our galaxy. This star gets its name from the Arabic word waqi meaning “falling”. This star is referred in many ancient cultures from the Polynesians to the Chinese. “For the Polynesians, the star was whetu o te tau, the year star. The Assyrians saw the star as Dayan-same, the "Judge of Heaven". (consevapedia) On July 16, 1860 Vega was the first star to be photographed other than the sun. (space) The star has a lite blue light which is so bright it has an apparent magnitude of 0.03. “Vega is 50 times brighter than sun and 27 light years away.” (potsdam) It is the brightest star in its constellation of Lyra and the fifth brightest in our galaxy. Lyra is shown as a vulture. In Greek mythology it is said this constellation is a harp played by Orpheus. This is the reason why Vega is sometimes referred as the Harp Star. Some other observations made were that this star rotates so quickly that it only takes about 12 hours to make a complete rotation. ” This rotation is so fast that observations suggest that the star is rotating at some 91 percent of the angular velocity needed to cause the star to physically fly apart. Vega is thus 23 percent wider along its equator than at its poles, as well as some 2300K cooler.” (consevapedia) Like earth, it is believed that liquid water could exist on this star. It is also believed that this star will be the next North Star. VY Canis Majoris also known as VY CMa was discovered roughly around March 7, 1801, by a French astronomer Jerome Lalande. (universetoday) Throughout the 19th century it was believed that VY Canis Majoris was a single star until 1917, Guerin noticed a three nuclei (Robinson, IBVS 599) the red hypergiant is the largest star known in The Milky Way but also in the entire universe. “It has a diameter of about 3 billion kilometres. Its radius is about 1,800 to 2,100 times the radius of the Sun.” (amazingfacts) VY Canis Majoris is about 40 times the mass of our sun. ” It has an average density of about 0.000005 to 0.000010 kg/cu.m. This is very less when compared to the density of water (1000 kg/cu.m).” (amazingfacts) This star is about 4,900 light years from the Earth. (universetoday) This star is found in the constellation of Canis Major which lies in the southern part of the sky. The name in Latin means “the greater dog”. This star is one of the most luminous stars. “Its luminosity is about 450,000 times the luminosity of the sun.” (amazingfacts) It is believed that this star is extremely unstable, as huge amounts of it’s mass it being thrown off into the closest nebulae. (amazingfacts) The sun is the most important star in our galaxy. It is the source of life on earth. Most of all ancient civilizations worshiped the sun as a god. “The sun god was called Ra in Egypt; Helios is Greece, Marduk by the Babylonians, and Utu by the Sumerians.” (thinkquest) All of these civilizations found ways to worship the sun in religious practices. “The Sun Dance was an important ritual for the North American Plains Indians. Anasazi and Mayan people built sun observatories and used their findings to calculate time and weather patterns.” (tripod) Much of these civilizations did not know about the sun but had different views. “The ancient Chinese believed that the sun was being chased across the sky by a giant dragon. When the sun disappeared because it was being covered by the moon (an eclipse), they thought the dragon had swallowed the sun. They would then shoot arrows in to the sky, light firecrackers, to drive away this evil spirit.”(thinkquest) Later during the 20 century, many scientists, mathematicians and philosophers began making correct assumptions. Many of which became well-known such as Galileo, Aristotle and Pythagoras. Some characteristics the sun has are that it is divided into layers and zones. ” The solar atmosphere consists of the photosphere, chromosphere, a transition region and the corona. Beyond that is the solar wind, an outflow of gas from the corona.” (space) The center of the sun is called the core. It only takes up about a quarter of its surface is about 2 percent of the suns volume. After the core the radioactive portion follows, it makes up 70 percent of the sun. The last layer of the sun is the photosphere. This is the layer in which light casts through. “Temperatures there range from 11,000 degrees F (6,125 degrees C) at bottom to 7,460 degrees F (4,125 degrees C) at top. Next up is the chromosphere, which is hotter at up to 35,500 degrees F (19,725 degrees C) and is apparently made up entirely of spiky structures known as spicules typically some 600 miles (1,000 kilometers) across and up to 6,000 miles (10,000 kilometers) high.” (space) Lastly, is the transition region where it’s heated by the corona. “The corona generally ranges from 900,000 degrees F (500,000 degrees C) to 10.8 million degrees F (6 million degrees C) and can even reach tens of millions of degrees when a solar flare occurs.” (space) It is made up of 25 percent Helium and 75 percent Hydrogen. The sun is orbited by nine different planets; Mercury, Venus, Earth, Mars, Jupiter, Saturn, and Pluto. Pluto is no longer considered a planet. This star is the closest to us but is only considered an average sized star. Canopus, also known as Alpha Carinae is one of the many stars in our sky. This star is known to be the second brightest star in our galaxy. It gets its name from an ancient city in northern Egypt meaning “Golden Earth”. The reasoning being that this star gives off a yellowish color. Canopus is found in the constellation of Carina which is 74 light years away. Carina is Latin for the keel of a ship. ”Before the invention of the magnetic compass, the star served as a southern pole star for navigators in the northern hemisphere far south enough to view the star.” (consevapedia) Today this star is mainly used for space navigation due to its brightness and location. Canopus is classified as a rare yellow-white supergiant. Compared to the sun this star is 13,300 times brighter, has about 9 times the Sun’s mass and 71 times the suns diameter. “If it was in the center of our solar system it would extend to within 90 percent of Mercury's orbit.” (consevapedia) The estimated surface temperature of Canopus is 7280 K. This temperature is common for this type of star. Canopus has been around for billions of years and will continue to light up our sky for many more to come. Arcturus or Alpha Bootis is one of the oldest and brightest stars. Arcturus is about 37 light years away, which lies in the constellation of Bootes. This star is the brightest in its constellation and is easily found in the arc of the Big Dipper. Arcturus gets its name from the ancient Greek Arktouros, meaning Bear Guard. The red giant star has a mass of about the Sun’s. “It is notable for its particularly strong emission lines, meaning its atmosphere is dusty and low-temperature compared to that of a main sequence star.” (wisegeek) Although its mass is about that of the Sun’s, Arcturus is much larger. About 10 time larger in diameter and 100 times in luminosity. Arcturus is very well known for trailing off into space.
Proxima Centauri is recognized as the nearest star to the sun. It is only about 4.24 light years from the sun. This star was discovered in 1915 by Robert Innes, a Scottish astronomer and the director of Union Observatory in South Africa. (space) “He noticed that star had the same proper motion as Alpha Centauri; further studies confirmed that it was in fact very close to Alpha Centauri.” (universetoday) The distance between the two is 0.21 light years away. Centauri is a red dwarf in the constellation of Centaurus. Although Proxima is very close to our Solar System it is barley seen with the naked eye because of its low luminosity. The average of its density is approximately 40 times that of the Sun. This star carries a mass of an eighth of the Sun’s. (universetoday) This stars low mass causes its energy to be conveyed to its exterior by its movement instead of its energy being transferred through a radiative process. ” This convection means that the helium ash left over from the thermonuclear fusion of hydrogen does not accumulate at the core, but is instead circulated throughout the star.” (wisegeek)This means that Proxima will drain most of its fuel and will die off sooner.
Epsilon Eridani also known as 18 Eri is located in the northern part of the constellation of Erdanus, the River. It lies to the west of Rana and northwest of Zaurak. Epsilon is much cooler and smaller compared to the Sun and is also less luminous. Its distance is 10.5 light years away but is still able to be seen with the naked eye. “This star is the closest star known to have a planet.” (space) Its apparent magnitude is 3.73. These are only a couple of the billion famous stars that have been around and a part of our galaxy. Everyday new stars are being born while others are dying off. They light up our sky with beautiful constellations while entertaining us with stories that they bring.

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