Feb 12, 2010 ... The second (Type II) process occurs in very massive stars once all ... in the surrounding layers cause rapid (R-process) nuclear reactions ...
NASA Website
The theory of high energy nuclear stars depends on a theory of nuclear transparency and on a theory of nuclear evaporation. The transparency can be computed on the basis of a model proposed by R. Serber as soon as the interactions between the nucleons and the incident particle are known. The evaporation can be ...
Energy Citations Database
The ultraviolet spectra, obtained with the International Ultraviolet Explorer, of a sample of H II regions and the nuclear regions of spiral and elliptical galaxies are described. The star formation rates in the nuclei of spiral galaxies are similar to th...
National Technical Information Service (NTIS)
The study of galactic evolution involves three mechanisms for triggering star formation in interstellar clouds: (i) star formation triggered by a galactic spiral density wave, (ii) star formation triggered by shock waves from supernovae, and (iii) star formation triggered by an expanding H ...
We present an HST I-band Planetary Camera image of the nuclear region of NGC 4314, an anemic barred galaxy with recent star formation confined to a nuclear ring. These data resolve the nuclear ring into multiple sites of new star formation and resolve associated dust lanes into discrete clouds. ...
NASA Astrophysics Data System (ADS)
100 1000 10000 12 C/13 C 1 10 100 1000 10000 14 N/15 N 240-1 Novae/ Supernovae? Supernovae AGB Stars J. Most grains can be attributed to either asymptotic giant branch (AGB) stars or Type II supernovae important and unique constraints on nuclear processes occurring in these stars. Keywords: ...
E-print Network
Commemorating the atomic bombing of Hiroshima and Nagasaki during World War II, this book includes many articles from the "Bulletin of the Atomic Scientists", a publication dedicated to preventing nuclear war. The articles incorporate diverse perspectives on many nuclear�related subjects. The book includes articles by well�known ...
NSDL National Science Digital Library
Physicist William A.Fowler initiated an experimental program in nuclear astrophysics after World War II. He recalls here the Steady State versus Big Bang controversy and his celebrated collaboration with Fred Hoyle and Geoffrey and Margaret Burbidge on nucleosynthesis in stars. He also comments on the shift away from ...
. Properties of non-rotating and rapidly rotating protoneutron stars and neutron stars are investigated. Protoneutron stars are hot, lepton rich neutron stars which are formed in Type-II supernovae. The hot dense matter is described by a realistic equation of state which is obtained by ...
The explosion of a star supernova occurs at the end of its evolution when the nuclear fuel in its core is almost, or completely, consumed. The star may explode due to a small residual thermonuclear detonation, type I SN or it may collapse, type I and type II SN leaving a neutron star remnant. ...
DOE Information Bridge
The eigenfrequencies of the axial w-modes of oscillating neutron stars are studied using the continued fraction method with an equation of state (EOS) partially constrained by the recent terrestrial nuclear laboratory data. It is shown that the density dependence of the nuclear symmetry energy E{sub sym}({rho}) affects significantly ...
The eigenfrequencies of the axial w-modes of oscillating neutron stars are studied using the continued fraction method with an equation of state (EOS) partially constrained by the recent terrestrial nuclear laboratory data. It is shown that the density dependence of the nuclear symmetry energy Esym(?) affects significantly both the ...
The role of the nuclear equation of state in determining the fate of the collapsing cores of massive stars is examined in light of both recent theoretical advances in this subject and recent experimental measurements with relativistic heavy ions. The difficulties existing in attempts to bring the softer nuclear matter apparently ...
A study of the distribution of ionized gas in the nuclear regions of a statistically significant sample of 91 non-Seyfert spirals is reported. CCD interference band images isolating the bright emission-lines of H-alpha + forbidden N II (6548, 6583 A) have been used to map the distribution of ionized gas in the inner 1-2 kpc of these galaxies. The galaxies ...
The [C II] 157.74 ?m line is an important coolant for the neutral interstellar gas. Since [C II] is the brightest spectral line for most galaxies, it is a potentially powerful tracer of star formation activity. In this paper, we present a calibration of the star formation rate (SFR) as a function of the [C ...
... STAR Technology for Real Time Localization of Unexploded Ordnance ... II. STAR SENSOR: THEORY AND CONSTRUCTION ...
DTIC Science & Technology
Dynamic stability of supermassive stars with nuclear-energy generation, noting rotation and limiting
NASA Technical Reports Server (NTRS)
Properties of non-rotating and rapidly rotating protoneutron stars and neutron stars are investigated. Protoneutron stars are hot, lepton rich neutron stars which are formed in Type-II supernovae. The hot dense matter is described by a realistic equation of state which is obtained by extending ...
Association with National Standards .........................................................................ii. Life Cycles of Stars....................................................................................................1 ...
... THEORY), (*NUCLEAR ENERGY, NUCLEAR REACTIONS), NUCLEAR WEAPONS, URANIUM, FISSION, NUCLEAR PHYSICS, USSR. ...
We report on the structure of the nuclear star cluster in the innermost 0.16 pc of the Galaxy as measured by the number density profile of late-type giants. Using laser guide star adaptive optics in conjunction with the integral field spectrograph, OSIRIS, at the Keck II telescope, we are able to differentiate ...
necessary for nuclear fusion (which generates the energy in a star) to occur. The more massive a star, the greater the rate at which nuclear reactions can take ...
Stars with masses roughly ten times the mass of the sun die in violent explosions known as Type II supernovae. Element formation occurs in such massive stars both during the pre-explosion evolution and during the explosion itself. The pre-explosion burning takes place in a series of stages starting with the burning of hydrogen and ...
... LUMINOUS STARS IN THE NORTHERN MILKY WAY II ... Warner and Swasey Observatory LUMINOUS STARS IN THE NORTHERN MILKY WAY II ...
In Paper I, we followed the evolution of binary stars as they orbited near the supermassive black hole (SMBH) at the Galactic center, noting the cases in which the two stars would come close enough together to collide. In this paper, we replace the point-mass stars by fluid realizations, and use a smoothed-particle hydrodynamics code ...
We present time-resolved observations of the Wolf-Rayet + O star Binary CQ Cephei using the FUSE satellite. We acquired a series of observations of CQ Cephei and determined the structure of the bow shock zone formed when the winds of the two hot stars collide. CQ Cephei has the shortest period of all the known W-R+O binaries. The W-R ...
This book presents an insider�s history of U. S. nuclear strategy from the late 1940s to the early 1980s. The author describes how technology and nuclear war theory combined to provide diplomacy leading to a peace that often balanced precariously on the brink of nuclear disaster. The book tells the story of the small group of ...
... Title : Advanced Composites II (RESEP II). Volume II. Computer User's Manual for the STAR (Shell Transient Asymmetric Response) Code. ...
Chapter topics include relativistic particle motion, particle identification, particle interactions in emulsions, emulsion stars, electron and photon processes in emulsions, neutron measurements, epltome of particle behavior, applications in cosmic ray research, applications in nuclear physics, applications in earth sciences, applications in ...
Results of recent numerical, one-dimensional core collapse calculations for 10M/sub sun/, 15M/sub sun/ and 20M/sub sun/ population I stars are reviewed. The physics model is discussed, including recent improvements in the nuclear equations of state, and nuclear binding energies. None of the models produces prompt explosions as a direct ...
Nuclear Fusion The process of releasing energy by combining hydrogen ... Nuclear fusion appears to be the source of the energy of the Sun and of stars. ...
... interaction with materials. The third section discusses shock waves in the stars and interstellar space. Descriptors : *NUCLEAR ...
... PUBLIC OPINION), (*NUCLEAR WARFARE, DEFENSE SYSTEMS), ORDNANCE, NUCLEAR BOMBS, NUCLEAR EXPLOSIONS, FOREIGN ...
... Descriptors : (*NUCLEAR PHYSICS, USSR), (*NUCLEI, NUCLEAR STRUCTURE), (*NUCLEAR PHYSICS, NUCLEI), ATOMIC STRUCTURE ...
The author feels that pursuit of Star Wars and continued US nuclear testing is blocking progress toward the eventual worldwide elimination of nuclear weapons. It is also bound to reveal new ways to attack military or civilian targets that will, in turn, stimulate further searches for new types of offensive and defensive ...
The Universe emerged from its first three minutes with a composition consisting of hydrogen, deuterium, 3He, 4He, and 7Li. These isotopes constitute the primordial compositions of galaxies. Within galaxies, the synthesis of heavier elements from carbon through uranium is understood to occur during the normal evolution of stars and in supernova explosions of Types I and ...
Optical and near-UV spectroscopy of an emission-line filament in the low-velocity system of NGC 1275 has revealed the presence of a young star-forming region, as evidenced by a very blue continuum source coincident with line emission characteristic of H II regions. This is the first direct detection of star formation in gas thought to ...
... Title : NUCLEAR INTERFERENCE STUDIES II: A PHYSICS CODE FOR THE DYNAMICS OF HIGH-ALTITUDE NUCLEAR BURSTS. ...
the atomic bomb and led to civilian nuclear plants - - ITER seeks to harness nuclear fusion: the power the atomic bomb and led to civilian nuclear plants -- ITER seeks to harness nuclear fusion: the power of the Sun and the stars. BACK STAR POWER: ITER, BOLDEST ...
Jun 26, 2003 ... These occur at the end of a star's lifetime, when its nuclear fuel is ... This will cause a blast wave that ejects the star's envelope into ...
... Title : RED STAR SERIES ON THE PROBLEMS OF UTILIZING ATOMIC ENERGY. PT. V. THE NUCLEAR FUEL ENGINE,. ...
... 4 The Distribution of Nuclear Debris in the Star Dust Corridor ..... 4 The Stratospheric Burden of Strontium-90 During Early 1962 ..... 10 ...
This paper discusses the following topics: The Nuclear Physics Input; Nucleosynthesis in the Big Bang; The Sun; and Nucleosynthesis in Massive Stars.
Evolution of l.2 M sub solar Population II stars in the heliumburning phase is investigated, taking into account the effect of conversion of helium into carbon and oxygen on the mean molecular weight and on the nuclear energy generation. The stellar models consist of a hydrogen-rich envelope, a radiative pure helium zone, and ...
The Type II Cepheids include most intrinsic variables with periods between 1 and about 50 days, except for the classical Cepheids and the shortest semiregular variables of type M. The Type II Cepheids may be divided in groups by period, such that the stars with periods beween 1 and 5 days (BL Her class), 10-20 days (W Vir class), and ...
We present a census of H II regions in 50 pairs of interacting galaxies, carried out on CCD and ISIT narrow-band images from Kitt Peak, Lowell, and La Palma. Objects were identified objectively using peak finding at multiple Gaussian smoothing levels to allow for the fact that the larger H II regions are marginally resolved, and measured using aperture ...
Super star clusters (SSCs) are young and massive star clusters that contain hundreds to thousands of OB stars. Their masses are in excess of 10 5 -10 6 [Special characters omitted.] , suggesting that they could be the progenitors of globular clusters. The youngest SSCs are often embedded in their natal cocoons, thus their stellar ...
and the environment in which these can occur. (d) The evolution of stars � the life cycle of stars, from parameters of stars, � have learnt about the life cycle of stars, � know how to formulate the equations sources in stars, nuclear reaction cycles energy transport, ...
Asymptotic giant branch stars are red supergiant stars of low-to-intermediate mass. This class of stars is of particular interest because many of these stars can have nuclear processed material brought up repeatedly from the deep interior to the surface w...
variable stars and Population II stars. The former are reliable standard candles , ... In the study of extragalactic stellar populations, a plethora of ...
Presupernova models of massive stars are presented and their explosion by ''delayed neutrino transport'' examined. A new form of long duration Type II supernova model is also explored based upon repeated encounter with the electron-positron pair instability in stars heavier than about 60 Msub solar. ...
This research involved studies on the composition of peculiar stars and the interpretation of the results in light of the current, rapidly changing ideas on the evolution of stars and nucleosynthesis. Specific studies included emphasis on hot stars, inclu...
Mar 12, 2009 ... nuclear fusion reactions in previous generations of stars," said. Bobrowsky. " Those earlier stars expelled those elements into space and ...
This paper investigates the stability of the complete sequence of strange-matter stars with nuclear crusts against radial pulsations (acoustical modes). It is found that a broad class of white dwarf- like strange stars is stable against such pulsations. The same holds for the much denser strange stars, which are ...
LS IV-12.1 and ROB 162 are rare, hot (Teff=50 - 60,000K) subdwarf O stars of population II, evolving from the asymptotic giant branch to the white dwarf domain. FUSE spectra are proposed to determine the abundances of C,N,Si,P,S and Fe by means of NLTE model atmospheres. In the case of LS IV-12.1 its high radial velocity allows the photospheric resonance ...
The aim of these lectures is to introduce basic processes responsible for cooling of neutron stars and to show how to calculate the neutrino production rate in dense strongly interacting nuclear medium. The formalism is presented that treats on equal footing one-nucleon and multiple-nucleon processes and reactions with virtual bosonic modes and ...
Nucleosynthesis is the study of the nuclear processes responsible for the formation of the elements which constitute the baryonic matter of the Universe. The elements of which the Universe is composed indeed have a quite complicated nucleosynthesis history, which extends from the first three minutes of the Big Bang through to the present. Contemporary nucleosynthesis theory ...
... Accession Number : ADA377346. Title : Shooting Down a "Star" Program 437, the US Nuclear ASAT System and Present-Day Copycat Killers. ...
... Accession Number : AD0604519. Title : RED STAR SERIES ON ATOMIC ENERGY. PT. III. NUCLEAR REACTIONS,. Corporate ...
Using an equation of state for cold degenerate matter which takes nuclear forces and nuclear clustering into account, neutron star models are constructed. ...
A review is given of charged-particle nuclear reactions in stars. Topics covered include helium burning, nucleosynthesis, and the solar neutrino problem. (AIP)
Nuclear Physics and Astrophysics are both entrusted with the task of understanding nucleosynthesis and energy production in the stars. At high temperatures and densities present in explosive scenarii such as the early universe, cataclysmic binary stars (n...
National Laboratory :: Nuclear Sciences Division :: Relativistic Nuclear Collisions Relativistic Nuclear Collisions, NSD STAR event Last updated 3/06/07. Contact webmaster...
Science.gov Websites
The properties of degenerate star matter in the sphere of nuclear density have been considered. The passing threshold from the electron-nuclear phase to the phase of continuous nuclear matter has been found.
... Title : RED STAR SERIES ON ATOMIC ENERGY. PT. II. ... The effects of radiation on the human organism are also considered. ...
Anomalous abundance of carbon, barium and rare earths in Population II red-giant stars accounted for
In stellar models, the equation of state and opacity are, together with nuclear reaction rates, the fundamental material properties. The structure of a star is a result of (i) a balance of forces, (ii) a balance between the energy loss at the stellar surface and energy generation in the core and (iii) stationary energy transport ...
-evolving (1-10 million years) massive stars which return their nuclear ashes in explosive type II supernova. G. G. M. Tielens,3 Geoffrey C. Clayton,4 Albert A. Zijlstra,5 Margaret Meixner,1 Angela Speck,6 Tim
