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Science & Technology Review May/June 2008

Description: This month's issue has the following articles: (1) Biomedical Technology Has a Home at Livermore--Commentary by Cherry A. Murray; (2) Shaping the Future of Aneurysm Treatments--Livermore foam devices may offer significant advantages for treating some forms of aneurysms; (3) Ring around a Stellar Shell: A Tale of Scientific Serendipity--Using a three-dimensional model, Livermore scientists have solved a long-standing puzzle of stellar evolution; and (4) On Assignment in Washington, DC--Livermore… more
Date: March 19, 2008
Creator: Chinn, D J
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energy and Technology Review

Description: This journal contains 7 articles pertaining to astrophysics. The first article is an overview of the other 6 articles and also a tribute to Jim Wilson and his work in the fields of general relativity and numerical astrophysics. The six articles are on the following subjects: (1) computer simulations of black hole accretion; (2) calculations on the collapse of the iron core of a massive star; (3) stellar-collapse models which reveal a possible site for nucleosynthesis of elements heavier than ir… more
Date: March 1, 1983
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Stellar-opacity calculations. I. Lecture 2

Description: In this study of stellar structure, evolution, stability, and pulsation or explosion, there are three very vital pieces of physical information needed. We assume the composition is known from observations of assumption. To construct a model of a star we then need to know the nuclear generation rates which give the luminosity the star emits, the pressure and energy equation of state which determines the flow of radiation through the star. It is the equation of state and opacity that we will be d… more
Date: March 14, 1983
Creator: Cox, A. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Supergiant radial and nonradial pulsations. Lecture 10

Description: The stars that we consider here have luminosities above 10,000 solar luminosities and masses above 15 solar masses. We contact the 53 Per stars such as ..nu.. Ori, 10 Lac, and iota CMa at our lower luminosity limit, and at the most luminous limit, we have the famous stars eta Car, Cyg OB12, and P Cyg. Evolution tracks including a reasonable mass loss rate are given for 15, 30, 60, and 120 solar masses. It appears that our pulsators have masses less than 60 solar masses, but how do the most lumi… more
Date: March 14, 1983
Creator: Cox, A. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stellar-opacity calculations. II. Lecture 3

Description: We turn to the effects on opacities of atomic lines and molecular bands. It was the realization that these atomic lines were important for the opacity and the radiation flow in stars that allowed the field of stellar evolution to greatly flower in the 1960's and 1970's. Our understanding of stellar structure and evolution is now very deep.
Date: March 14, 1983
Creator: Cox, A. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Absolute Limit on Rotation of Gravitationally Bound Stars

Description: The authors seek an absolute limit on the rotational period for a neutron star as a function of its mass, based on the minimal constraints imposed by Einstein`s theory of relativity, Le Chatelier`s principle, causality and a low-density equation of state, uncertainties which can be evaluated as to their effect on the result. This establishes a limiting curve in the mass-period plane below which no pulsar that is a neutron star can lie. For example, the minimum possible Kepler period, which is a… more
Date: March 1, 1994
Creator: Glendenning, N. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Stellar alchemy: The origin of the chemical elements

Description: What makes the stars shine? This question puzzled human beings for thousands of years. Early in this century, chemists and physicists discovered radioactivity; and the nuclear model of the atom was developed. Once nuclear reactions were produced in the laboratory, it did not take long before their role in stellar energy generation was realized. The theory that nuclear fusion is the source of stellar energy was initially developed in the 1930`s and was elaborated in detail in the 1950`s. Only wi… more
Date: March 13, 1994
Creator: Norman, E. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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On the quasihydrostatic flows of radiatively cooling self-gravitating gas clouds

Description: Two model problems are considered, illustrating the dynamics of quasihydrostatic flows of radiatively cooling, optically thin self-gravitating gas clouds. In the first problem, spherically symmetric flows in an unmagnetized plasma are considered. For a power-law dependence of the radiative loss function on the temperature, a one-parameter family of self-similar solutions is found. The authors concentrate on a constant-mass cloud, one of the cases, when the self-similarity indices are uniquely s… more
Date: March 1, 1995
Creator: Meerson, B.; Megged, E. & Tajima, T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The effects of metallicity on {delta} Scuti star asteroseismology

Description: In {delta} Scuti star seismology, most researchers use evolution and pulsation models assuming a solar element mixture and Z = 0.02 for preliminary determinations of stellar masses or evolutionary state from observed frequencies. Here the authors investigate the consequences of this assumption by considering the effects of metallicity changes in the models on their inferences of the internal structure of {delta} Scuti stars. They use the main-sequence {delta} Scuti star FG Vir, and the more evo… more
Date: March 1, 1998
Creator: Guzik, J.A.; Bradley, P.A. & Templeton, M.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Processes and problems in secondary star formation

Description: Recent developments relating the conditions in molecular clouds to star formation triggered by a prior stellar generation are reviewed. Primary processes are those that lead to the formation of a first stellar generation. The secondary processes that produce stars in response to effects caused by existing stars are compared and evaluated in terms of the observational data presently available. We discuss the role of turbulence to produce clumpy cloud structures and introduce new work on collidin… more
Date: March 1, 1984
Creator: Klein, R. I.; Whitaker, R. W. & Sandford, M. T., II
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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