Hertzprung-Russell Diagram, Star Is Born - Essay Example

?Synopsis: This is a three page APA citation style essay which will address the following questions Explain how the Hertzprung- Russell diagram is constructed of four main groupings of stars. Identify the characteristics of the four main grouping of stars. 2) A “ star is born”! In a step by step fashion, reconstruct include stellar medium, protostar and how stellar equilibrium is reached. 3). “A star dies”. Using the same technique applied in question 2, trace the elements within the demise of a star with low stellar mass and those that are very massive. 4). Explain how type I and Type II. Supernovae occur. 1). The four main grouping of stars as depicted by the Hertzprung- Russel diagram are dwarf (white and red) stars, main sequence grouping stars, giant stars and supergiant stars (p. 142). The white dwarf stars are Sirius B, Wolf 486, Van Maanen's star, Procyon B, Wolf 1346 and 40 Eridani B. The size characteristic of these stars is ranging from 0.008 R to 0.03 R. The stars in the white dwarf category have temperatures ranging from 5,000 K to 25, 000 K. In between the white dwarf stars and the main sequence grouping we have Bernard's star. Bernard's star is a red dwarf. It has a radius of about 0.1 R and 150 L/L. Bernard's star is also the coolest star with temperatures of 2900 K. The white and red dwarf stars have Mv > 15. The main sequence stars are Aldebaran B, Alpha Centauri B, the Sun, Altair, Sirius, Procyon A, Vega, Rigel B, Pollux, Spica B, Spica A, Adara and Capella B. The luminosity class of these stars is V. The size of these stars vary from 1R to 10R. The stars in the main sequence grouping vary from 7,000 L/L to 85,000 L/L. The main sequence grouping stars have temperatures ranging from 3700 K for Aldebaran B to 30,000 K for Adara. The main sequence stars have between 5- 10 Mv. The next sequence of stars are the giants. Included in the giant classification of stars are Capella A, Aldebaran A, Arcturus, Mira and Canopus. The giant classification of stars have radii which vary from 10 R to 100 R. The luminosity class of the giant stars are III. The giant stars have a Mv between 0- 5. The next sequence is the supergiant sequence of stars. This includes Polaris, Deneb, Rigel A and Alnilam. The supergiants temperatures range from 10,000 K to 30,000K. The luminosity class is Ib. The largest stars are Betegeuse and Antares,.Betelgeuse has a size of 1000 R. Antares has a size of about 2000 R. The Mv for these stars is – 5 (p. 143). 2). A star is born from the thin gases of space. When a star is born, there is normally a large cloud of gas and dust. The thin gases of space are known as the interstellar medium ( p. 162). When enough hydrogen is compressed through the gravity of these stars, hydrogen fusion is achieved. In the center core of these stars there is a helium core. A teaspoon of mass of helium from the center of a star would weigh more than a ton. When enough helium is compressed in the center of the star, there is an abrupt explosion of intense magnitude called a helium flash. For this particular moment in time, the center of the newly born star produces more energy per second than an entire grouping of stars. This helium flash causes the center of the star to increase in temperature, whereas a great number of electrons become excited by the reaction. This causes the hydrogen to fuse into helium. At that point, the star is born with a self sustaining hydrogen fusion reaction at its shell. Often there is a helium fusion reaction at the center of the star. The size of the star is of the utmost importance, stars less than 0.40 solar masses never get enough energy to continue the helium fusion reaction process. Stars which are greater than 3 solar masses experience degeneration at their core before this phenomenon occurs (p. 187). In the star there are two types of fusion reactions, helium fusion at the center and hydrogen fusion at the shell. 3). A star begins to die when the helium fusion which occurs at its center begins to produce carbon, oxygen and neon. As the fusion reaction continues, the oxygen atoms form a non reactive center which becomes too cool to sustain the helium fusion reaction. The supergiant stars have a non reactive carbon center which is surrounded by a helium fusion layer. This helium fusion layer is covered by a hydrogen fusion layer. When a star such as that of the Sun dies, it evolves into a white dwarf star. Stars which are between 0.08 and 0.4 solar mass have the benefit of having a lighter mass and a relatively low pressure to temperature relationship. This causes the hydrogen shell to convert to helium at a very slow pace. Red dwarf stars contain hydrogen fusion reactions at their core and their center. Theoretically, the life span of a red dwarf star is over one hundred billion years (p.190). 4). Type I supernovae manifest no hydrogen lines in the spectra. A supernova may occur when a white dwarf star in a binary system which is absorbing mass surpasses the Chandrasekhar tolerance and implodes. When this implosion occurs with a white dwarf star, the temperature and density rise dramatically. As a result the carbon- oxygen center creates a violent nuclear explosion. The resulting explosion expels the hydrogen shell. The explosion which results is 600% more luminous than a type II supernova. The white dwarf star is completely consumed by the resulting explosion. The type Ib supernova occurs when a giant star in a binary system has its hydrogen outer shell extracted by the gravity of a neighboring star (p. 203). The probability of an event involving a white dwarf star evolving into a supernova is extremely scarce. Stellar events called supernovae occur, as demonstrated in 185 AD, 386 AD, 393 AD, 106 AD, 1054 AD, 1572 AD (Tycho's supernova and 1987 AD. As these stellar events called supernovae occur, the resulting emissions are called neutrinos. This occurs when the center of a star compresses into an iron core. This causes the star to implode and explode with an explosion which blasts away its outer hydrogen shell. Cassiopeia A is an example of a supernova remnant (p. 205). Read More