Th Bsi hysis Gvrning Str Frmtin - Literature review Example

Institution: Name: Date: THЕ BАSIС РHYSIСS GОVЕRNING STАR FОRMАTIОN Astronomy is a branch of science that deals with the study of celestial bodies. Examples of such celestial bodies include; galaxies, moons, planets, comets, asteroids, nebulae and stars. It is also involved in the study of another process like gamma-ray bursts, cosmic microwaves radiations, and supernovae explosions. (Astronom et al., 2010 pp1-6) also deals with the chemistry, evolution, and physics of all the phenomena that have their origin out of the earthly atmosphere. Astronomy has two branches which split in the 20th century. The two branches are the theoretical branch and observational branch. In the theoretical branch, it is centrally based on the development of models that are analyzed to illustrate astronomical phenomena and objects (Chandrasekhar, 1943 pp 1-3). On the other hand, observational branch deals with the acquisition of data based on observations of some objects of astronomy, and then the data is clearly analyzed by the use of basic physics principles (Marchesini et al., 2009 p 1765). However, the two branches work together as they complement one another, theoretical astronomy tries to explain the findings by the observable astronomy (Conley et al., 2010 p 133). The observations and findings by observational astronomy on the hand tend to confirm the results that are made by the theoretical astronomy. The solar system is made up of the planets and the sun which is the main source of light energy and heat energy. The solar system also consists of meteoroids, comets, and asteroids contained in the planets (Mihalas, and Binney, 1981 p 608). Terrestrial planets which are the four planets closer to the sun have rocky surfaces and thus, they bear the name terrestrial planets. Gas giant planets are the large planets. The planets have their own atmospheres which have a different composition of gasses. For instance, Earth mainly has oxygen and nitrogen (Lafreniere et al., 2007 p 1367). Other planets such as Venus have carbon dioxide and traces of poisonous gasses. Stars, as studied in astronomy, can be defined as an illuminating plasma sphere fixed in place by its own gravity. The sun is said to the nearest star to the earth service. The star can be seen at night due to their luminous nature (Charbonneau et al., 2002 p 377). Astronomers have tried to explain the process of star formation using the two branches of astronomy; a star starts to form when a gravitational instability occurs within the molecular cloud. The gravitational occurs due a higher density that is triggered by a radiation from stars that creates a great compression to the clouds. The molecular clouds consist of a dense interstellar gas and dust concentration. This zone is made up of very low temperatures of about 15K above the absolute zero. The low temperature indicates that the gasses in the region are in molecular form (Scoville et al., 2007 p 1). The common gasses in the region are H2 and CO. this region does not allow light pass through since the region its self is dense enough. Astronomers study the region by the help of radio telescopes and IR because in optical light the dark nebula will not shine. The stars start to form immediately when collapsing of the dense cloud core occurs as a result of their gravity. The referred core within the cloud has a higher density compared to the outer part of the cloud, with masses of 104 solar masses which takes the form of dust and masses. Clumps are formed when the core collapse. The clumps formed are of sizes that range between 10-50 solar masses (Amanullah et al., 2010 p 712). Later the clumps lead to the formation of protostars. The process of protostar formation is not fast. It takes a long period of years not less than 10 million years. Figure1, showing formation of protostars A star takes about 50 million years to be mature. The hydrogen nuclear fusion leads to the formation of helium in their interior. The pressure required to keep the star free from collapsing under its gravity is provided by energy outflow from its interior (Neugebauer, 2012 P 103). The energy from its interior is the one responsible for its shining too. The stars are also classified into different categories, small stars (red dwarfs), they contain about 10% of the mass of the sun, also red dwarfs emits 0.01% energy and a temperature of ranging between 300-400k. These stars are the most within the universe with a lifespan of 10 billion years (Rohlfs, and Wilson, 2013 p 42). The other category of stars is the hypergiant stars. These stars are more massive than the sun to about 100 times that of the sun. The surface temperature of the hypergiant stars is approximately 30,000k.The life span is less than that of the red dwarfs (Zwicky, 2012 P 21). The have a life span of several million years. These hypergiants produce a lot of energy compared to the sun (Sanders et al., 2007 p 86). These massive stars are very few the current worlds as compared with the early universe. Figure2. Stages of cloud formation In the process of cloud formation, we may assume that a cloud had a radius of R and the cloud is of mass M with N particles. Each particle has an average mass m, from the above information it is easy to find the gravitational potential energy as follows; U=-q (GM2)/R. q= mass distribution factors and is assumed to be q~1. There are also other theories that explain the formation of the stars. The two theories are; low mass star formation and the second theory is high mass star formation. The low mass star formation theory argues that the low mass stars arise from the collapsing of the rotating gravity of the molecular clouds due to the gravitational rotation (Scoville et al., 2007 P 38). It is should be noted that the clouds with the dense cores undergo gravitational collapse, with the following features, the central density peak runaway growth, evolving to the singularity. However, magnetic fields and rotation do not affect the qualitative behavior even if clouds collapse. Today, star formation can be estimated by use of various techniques that enable us to understand the concept. The first technique is radio continuum emission. This technique can be proved statistically since it correlates statistically with the IR radiation. This method applies a lot of physics knowledge (Lauer et al., 2007 p 808). Synchrotron radiation is the main source of radio emission. The other technique is the far-infrared flux, this method is based on an assumption that a fixed fraction of the stellar energy emitted goes to an absorption by the dust. The far-Ultraviolent flux method which traces the young stars as well as the massive stars that already has scattered their dust and gas. H α emission is a technique that is used to the rate at which any given star is forming instantaneously. The process of star formation occurs in deep space; therefore, it is not easy to discern the process of accretion (Ilbert et al., 2010 p 644). Computer simulations and the theoretical models, however, assist in the discernment of this crucial process of star formation. The accretion disc contains different components like; dust, plasma, and also other materials. Most stars have either a binary or multiple system of formation where there is a gravitational interaction that plays a role in the redistribution of the momentum resulting to disk accretion (Bouwens et al., 2010 p 133). In conclusion, astronomers have tried to study the components of the celestial bodies. The task involves a lot of scientific knowledge. The astronomers require chemistry to analyses the observations made by the astronomers. Social sciences are also required in the analysis of the data collected. An example of a social science that is highly applicable is statistics. Astronomers deal with data collection, analyses of the data and also the interpretation of the data accordingly in order to make correct deductions (Conley et al., 2010 p 1). Mathematical disciplines are also applied in astronomy. Astronomers in the current world have built the knowledge on the astronomy and have more detailed techniques compared to the earlier astronomers. The development of the technology has enabled astronomers to ease their study References Amanullah, R., Lidman, C., Rubin, D., Aldering, G., Astier, P., Barbary, K., Burns, M.S., Conley, A., Dawson, K.S., Deustua, S.E. and Doi, M., 2010. SPECTRA AND HUBBLE SPACE TELESCOPE LIGHT CURVES OF SIX TYPE Ia SUPERNOVAE AT 0.511< z< 1.12 AND THE UNION2 COMPILATIONBased in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute (STScI). STScI is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under the NASA contract NAS 5-26555. The observations are associated with programs HST-GO-08585 and HST-GO-09075. Based, in part, on observations obtained at the ESO La Silla Paranal Observatory (ESO programs 67. A-0361 and 169. A-0382). Based, in part, on observations obtained at the Cerro-Tololo Inter-American Observatory (CTIO), National Optical Astronomy Observatory (NOAO). Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT). Based, in part, on observations obtained at the Gemini Observatory (Gemini programs GN-2001A-SV-19 and GN-2002A-Q-31). 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Detection of an Extrasolar Planet AtmosphereBased on observations with the NASA/ESA Hubble Space Telescope (HST), obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. The Astrophysical Journal, 568(1), p.377. Conley, A., Guy, J., Sullivan, M., Regnault, N., Astier, P., Balland, C., Basa, S., Carlberg, R.G., Fouchez, D., Hardin, D. and Hook, I.M., 2010. Supernova Constraints And Systematic Uncertainties From The First Three Years Of The Supernova Legacy Survey. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada. The Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products.... The Astrophysical Journal Supplement Series, 192(1), p.1. Hoekstra, H., Mellier, Y., Van Waerbeke, L., Semboloni, E., Fu, L., Hudson, M.J., Parker, L.C., Tereno, I. and Benabed, K., 2006. First Cosmic Shear Results from the Canada-France- Hawaii Telescope Wide Synoptic Legacy SurveyBased on observations obtained with MegaPrime equipped with MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products .... The Astrophysical Journal, 647(1), p.116. Ilbert, O., Salvato, M., Le Floc'h, E., Aussel, H., Capak, P., McCracken, H.J., Mobasher, B., Kartaltepe, J., Scoville, N., Sanders, D.B. and Arnouts, S., 2010. GALAXY STELLAR MASS ASSEMBLY BETWEEN 0.2< z< 2 FROM THE S-COSMOS SURVEYBased on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc., under NASA contract NAS 5-26555. Also based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. Also based on data collected at: the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory under Large Program 175. A-0839, Chile; Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by the Association of Universities for Research in Astronomy, Inc.(AURA) under cooperative agreement with the National Science Foundation; and the Canada-France-Hawaii Telescope with MegaPrime/MegaCam operated as a joint project by the CFHT Corporation, CEA/DAPNIA, the NRC and CADC of Canada, the CNRS of France, TERAPIX, and the University of Hawaii. The Astrophysical Journal, 709(2), p.644. Lafreniere, D., Doyon, R., Marois, C., Nadeau, D., Oppenheimer, B.R., Roche, P.F., Rigaut, F., Graham, J.R., Jayawardhana, R., Johnstone, D. and Kalas, P.G., 2007. The Gemini Deep Planet SurveyBased on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina). The Astrophysical Journal, 670(2), p.1367. Lauer, T.R., Faber, S.M., Richstone, D., Gebhardt, K., Tremaine, S., Postman, M., Dressler, A., Aller, M.C., Filippenko, A.V., Green, R. and Ho, L.C., 2007. The Masses of Nuclear Black Holes in Luminous Elliptical Galaxies and Implications for the Space Density of the Most Massive Black HolesBased on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with GO and GTO proposals 5236, 5446, 5454, 5512, 5943, 5990, 5999, 6099, 6386, 6554, 6587, 6633 .... The Astrophysical Journal, 662(2), p.808. Marchesini, D., Van Dokkum, P.G., Natascha, M.F., Franx, M. and Wuyts, S., 2009. THE EVOLUTION OF THE STELLAR MASS FUNCTION OF GALAXIES FROM z= 4.0 AND THE FIRST COMPREHENSIVE ANALYSIS OF ITS UNCERTAINTIES: EVIDENCE FOR MASS-DEPENDENT EVOLUTIONBased on observations with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology under NASA contract 1407. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract .... The Astrophysical Journal, 701(2), p.1765. Mihalas, D. and Binney, J., 1981. Galactic astronomy: Structure and kinematics. San Francisco, CA, WH Freeman and Co., 1981. 608 p. 1. Neugebauer, O., 2012. A history of ancient mathematical astronomy (Vol. 1). Springer Science & Business Media Sanders, D.B., Salvato, M., Aussel, H., Ilbert, O., Scoville, N., Surace, J.A., Frayer, D.T., Sheth, K., Helou, G., Brooke, T. and Bhattacharya, B., 2007. S-COSMOS: The Spitzer Legacy Survey of the Hubble Space Telescope ACS 2 deg2 COSMOS Field I: Survey Strategy and First AnalysisBased on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555; also based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an .... The Astrophysical Journal Supplement Series, 172(1), p.86. Rohlfs, K. and Wilson, T., 2013. Tools of radio astronomy. Springer Science & Business Media. Scoville, N., Abraham, R.G., Aussel, H., Barnes, J.E., Benson, A., Blain, A.W., Calzetti, D., Comastri, A., Capak, P., Carilli, C. and Carlstrom, J.E., 2007. COSMOS: Hubble Space Telescope ObservationsBased on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. The Astrophysical Journal Supplement Series, 172(1), p.38. Scoville, N., Aussel, H., Brusa, M., Capak, P., Carollo, C.M., Elvis, M., Giavalisco, M., Guzzo, L., Hasinger, G., Impey, C. and Kneib, J.P., 2007. The Cosmic Evolution Survey (COSMOS): OverviewBased on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555; also based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; the European Southern Observatory .... The Astrophysical Journal Supplement Series, 172(1), p.1. Zirm, A.W., van der Wel, A., Franx, M., Labbé, I., Trujillo, I., van Dokkum, P., Toft, S., Daddi, E., Rudnick, G., Rix, H.W. and Röttgering, H.J.A., 2007. NICMOS Imaging of DRGs in the HDF-S: A Relation between Star Formation and Size at z~ 2.5 Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 9723. The Astrophysical Journal, 656(1), p.66. Zwicky, F., 2012. Morphological astronomy. Springer Science & Business Media. Read More