Pherkad stands out as one of the most significant stars of the Ursa Constellation because of its confusing variability changing over less than a tenth of a magnitude within a short period. It also stands out as one of the brightest and warmest stars in the constellation and 175th in the universe. The star is interesting because of the rapid revolutions it keeps making around the sun despite the many years of its existence. It is one of the oldest stars with about 100 million years. Someone should take time to read this report because it presence clear facts and mythology relating to the star.
Pherkad is a white giant star that glows in the mid-third magnitude of 3.00 in the core area of the Little Dipper. It is the third brightest star in the Little Dipper, and it moves through the galaxy at an estimated speed of 18.2 km/s relative to the sun (Grego 17). It is also believed that Pherkad is the 175th brightest star in the universe. The star has kept evolving over the years with the presence of the helium core surrounded by hydrogen that is regularly fusing. Its temperatures and luminosity project an estimated mass of around 4.8 times solar hence indicating an age of over 100 million years (Simpson 8). The evolution also means that the star will continue being brighter and easily visible from different parts of the earth. The extreme heat and brightness of the star makes it difficult for many people to classify it, as it is believed to exhibit unique characteristics. Accordingly, Pherkad remains a star of interest for many individuals because of its subtle and confusing variability, changing over less than a magnitude in a short period.
This essay explicates the star, Pherkad highlighting the myth of its constellation, diverse properties, and the life cycle of the star.
Origin of Name and Constellation of Myth or History
The name of the star is a proper name. The origin of the name, Pherkad, is attributed to the Arabic language. It is worth noting that the names emanates from the Arabic words for ‘the dim one of the two calves’. The word initially referred to both Pherkad and Kochab, and they have been traditionally referred to as the “Guardians of the Pole” because of their behavior of forming a circle around the Polaris. However, Pherkad was later distinguished from Kochab because of its warmth arising from temperatures of 8280 Kelvin (Simpson 33).
It is in the Ursa Minor constellation, which is located in the northern sky. It is also referred to as the Little Bear or the Little Dipper, and is one of the significant 48 constellations that Ptolemy listed in the 2nd century. The constellation has been traditionally visualized as a baby bear with a unique long tail. It is made up of seven bright stars that were commonly referred to as Hesperides in the early Greek mythology. Thales of Miletus is credited with the invention of Ursa Minor around 600 BCE from the wings of the Dragon and Draco (Grego 54). His desire to commemorate the location of the North Celestial Pole motivated him to come up with the constellation that is currently recognized around the globe.
The Hungarian mythology also presents some preview on the origin of the constellation. In the Hungarian mythology, the constellation is commonly referred to as ‘Little Goncol cart’, and this comes from the legendary inventor Shaman. Shaman had limitless knowledge, and disappeared into the stars hence leading to the formation of the constellation. The wide knowledge has also contributed to the brightness of the stars that constitute the constellation.
The table presents the key properties of the star, Pherkad. The first key property relates to its coordinates. In tandem with the coordinates, it has a right ascension (R.A.) of 15h 20m 43.71604s. More so, it has a declination of +170 50’ 02.4596’, as shown in the table above. The second property is the distance and its parallax (Simpson 62). The distance is believed to be at around 487 plus or minus 8 ly (149 plus or minus 2pc). The parallax is 6.70 plus or minus 0.11 mas.
The third vital properties of the star could be drawn from its proper motion. The proper motion has a right ascension (R.A.) or -17.73 mas/yr while the declination is +17.90 mas/yr. These indicate the rapid variability of the star over the years (Grego 61). Another property could be seen from the spectral type and luminosity class. The spectral type is A3 lab, U-B color index +0.08 B-V color index +0.09. Additionally, the luminosity class is 1,100 Lo.
There is also a high surface temperature of 8280 Kelvin, which boosts its evolution over time and hours of its movement around the sun. The high surface temperature has been instrumental in bringing the star out, as one of the warmest in its constellation. In fact, it holds the third position, as the warmest and the brightest star.
It also heavy with a mass of 9.945E 30 kgs (5 times solar mass), which has played a significant part in its continuous changes (Grego 93).
Pherkad is a binary star with a 21,00 to 27,700 light years from the center of the galaxy. It has a radius of 10,430,000 km, which is about 15 times that of the sun (Grego 77). The speed at which the star revolves has played a vital role in the current improvements that have been noticed on it in terms of warmth and light. With a massive distance of 486 light years, it remains one of the brightest stars in the Ursa Minor constellation.
Life Cycle of the Star
The position of the star on the Herzsprung-Russell (H-R) Diagram indicates that it holds a radius that is more than 15 times that of the sun. This means that it is a bit far away from the sub, but is associated with rampant nuclear fusion. The star generates its energy by illuminating some of it from the sun. This explains the excessive heat it generates on the daily basis. The immense energy illuminated from the sun is always vital for the creation of this energy. Other stars in the constellation also generate their energy through illumination from the sun. In line with the position of the star in the H-R Diagram, it is clear that it is still evolving at the fastest rate possible. The current temperatures of 8280 Kelvin have played a vital role in enhancing the level of the star’s evolution over the years (Simpson 82). Pherkad has continues to spin rapidly with over 175 kilometers per second over the equator, which ensures that its components are always stirred and normal. The continuous travels on the H-R diagram could transform the star into a Cepheid variable. The presence of the quite helium core surrounded by fusing hydrogen has presented an effective opportunity for rapid fusion on the star. The fusing hydrogen also sets the ground for the creation of more energy, which ensures the star remains one of the brightest and warmest at any given time. Being a class A star, it tends to have an odd chemical composition that results into selective settling and lofting of atoms in the quite atmospheres. The giant mass of 9.945E 30 kgs (5 times solar mass) has also been vital in quickening the process of its evolution over the years (Grego 26). It also quickens the process, by ensuring it only takes a few hours.
The star us yet to day. However, it is predicted that once it comes to the end of its life it will first turn into an ordinary giant much like the Kochab. The only difference is that it will be brighter. After losing its outer layers, it will leave behind a fairly massive white dwarf. Therefore, the star has an estimated age of 100 million years, and there has been no prediction of the exact date when it might die. The evolution process will key to the realization of any future changes.
In conclusion, the essay has highlighted the view that Pherkad is a giant star in the Ursar Minor constellation. The name of the star has its roots to the Arabic language, and it stands out as the third brightest star in the constellation. Again, the essay has brought out the view that the origin of the constellation is linked to both the Hungarian and Greek mythology, which give diverse perspectives on its existence. For instance, the Greek mythology credits Thales of Miletus with the invention of the constellation. On the other hand, the Hungarian mythology credits Shaman for the origin of the constellation because of his massive knowledge on different matters. The star is still in the evolution process and would result into a white dwarf when it finally dies in the coming years. There has been continuous research on the star, because of its mythological richness, and rapid variation.