Solar wind gases, cosmic-ray spallation products and the irradiation history of Apollo 11 samples
Apollo 11 lunar soil irradiation history from solar wind rare gas abundances and cosmic ray spallation products
Lugmair, G. W.↗
SEARCH · Engineering Papers
Results for “solar abundances”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Aspects of the condensation of primordial silicates
Mafic silicates condensation in primordial solar nebula, explaining meteoritic abundance patterns by two component elemental volatility model and trace element distribution
Kerridge, J. F.↗
Interstellar lines in the ultraviolet spectrum of zeta Oph
Interstellar lines arising in carbon, oxygen, silicon, and sulfur observed in the ultraviolet spectrum of zeta Oph by rocket spectrographic techniques were analyzed. Within a factor of 10, the abundances of c(+), neutral 0, and Si(+) outside the H II region surrounding zeta Oph, relative to the hydrogen abundance, are equal to solar values. The lines in neutral C and S(+) imply that the interstellar matter is distributed among several clouds as indicated by high resolution visible spectra. It is suggested that the excited C(+) ions are inside the Stromgren sphere where proton densities equal to or greater than 0.0022 cm can collisionally excite the ions at sufficient rates. Stellar absorption lines of C IV (1548.2, 1550.8A) and N V (1238.8, 1242.8A) were observed shifted to lower wavelengths, indicating stellar mass loss.
Smith, A. M.↗
The anomalous abundance of cosmic ray nitrogen and oxygen nuclei at low energies
Recent measurements using a cosmic ray telescope on the Pioneer 10 spacecraft have revealed an anomalous spectrum of nitrogen and oxygen nuclei relative to other nuclei such as He and C, in the energy range 3-30 MeV/nuc. The intensity of nitrogen and oxygen nuclei is enhanced by a factor of up to 20 relative to their abundance in galactic or solar cosmic rays.
Mcdonald, F. B.↗
Irradiation history and accretionary processes in lunar and meteoritic breccias
Particle track studies reveal an abundant record of fossil solar flare tracks in breccia components. Metamorphic events govern the degree to which this record is preserved, and studies of phases with different track retentivities allow limits to be placed on temperatures reached during a rock's history. The least affected breccias have never experienced temperatures as great as 300 C. Two breccias which contain xenon from spontaneous fission of Pu-244 (14301 and 14318) and Xe-129 (14301 only) have never been heated above about 700 C. This and evidence for a surface irradiation of some of the breccia components support a surface implantation model for the origin of the xenon in these breccias. Green glass spheres in 15086 have not been heated above about 300 C during or after breccia formation yet have retained fission tracks for less than 0.7 G.y. Argon ages of about 3.5 G.y. for similar green glass are at least five times as great and may indicate that the glass was not completely outgassed at is formation.
Macdougall, D.↗
Relative abundances of nuclei with Z between 2 and 36 in solar flares
Explore the source record for details and available documents.
Sullivan, J. D.↗
The anomalous abundance of cosmic-ray nitrogen and oxygen nuclei at low energies
Recent measurements using the Goddard-University of New Hampshire cosmic-ray telescope on the Pioneer 10 spacecraft have revealed an anomalous spectrum of nitrogen and oxygen nuclei relative to other nuclei such as He and C, in the energy range 3-30 MeV per nucleon. The intensity of nitrogen and oxygen nuclei is enhanced by a factor of up to 20 relative to their abundance in galactic or solar cosmic rays. It is argued that this is most likely a new extrasolar component of cosmic rays.
Mcdonald, F. B.↗
Homeostatic tendencies of the earth's atmosphere
The concept is developed that the atmosphere of the earth flows in a closed system controlled by and for the biosphere. The environmental factors delimiting the biosphere are examined. It is found that neither oxygen nor pressure per se limit the distribution of life as a whole. Rather the major physical variables determining the distribution of organisms are solar radiation, temperature, water abundance, and the concentrations of hydrogen and other ions and elements. An attempt is made to model temperature and atmospheric composition of a lifeless earth.
Lovelock, J. E.↗
CNO abundances and hydrodynamic models of the nova outburst. II - 1.00 solar mass models with enhanced carbon and oxygen
Results of a computation of a variety of evolutionary sequences involving thermonuclear runaways in the hydrogen-rich envelopes of 1.00-solar-mass carbon-oxygen white dwarfs. The evidence concerning the location of the outburst in the nova system is reexamined, and it is concluded that the white dwarf is the seat of the outburst. An order-of-magnitude argument is presented which indicates that for a 1.00-solar-mass white dwarf it is impossible to achieve mass ejection without an energy generation of approximately 10 to the 16th ergs/g/sec. A description is given of models with low nuclear enhancements that do not produce an outburst, although their evolution has certain implications for the cause of the dwarf-nova outburst. The results for models that produced a nova outburst are then presented, and on the basis of these results it is found possible to explain continuous ejection, Kukarkin and Parenago's (1934) relationship, and other gross features of the nova phenomena.
Starrfield, S.↗
Laboratory studies of actinide partitioning relevant to 244Pu chronometry
Actinide partitioning and light lanthanide fractionation have been studied to gain an understanding of Pu chemistry under meteoritic and lunar conditions. The goal of the study was to identify conditions and samples from which chronological information can be retrieved. The laboratory investigations involved particle track radiography of the crystal/liquid partitioning of Th, U and Pu among diopsidic clinopyroxene, whitlockite and liquid. It is found that trivalent Pu plays an important role in partitioning for lunar and most meteoritic conditions. The use of Pu/Nd for relative age assessments is supported to some extent by the investigations; samples with unfractionated U, Th and Nd abundances (relative to average solar system values) may be suitable for Pu chronometry.
Benjamin, T.↗
Preliminary estimates of mass loss from O-type stars
P Cygni profiles of C IV resonance lines (observed for O-type stars) taken with the high resolution spectrograph on IUE are presented, and data indicate that terminal velocity is proportional to photospheric escape velocity. Parameters determining these line profiles are stellar radius, mass loss rate, the velocity law, the abundance (assumed to be solar) of the absorbing ion, and atomic parameters such as wavelength and oscillator strength, while the ionization fraction is assumed to be the same as that of Zeta Pup (Lamers and Morton, 1976). Thus an electron temperature of 200,000 K, a radiation temperature of 30,000 K and an electron density of 10 to the 10th are adopted. It is concluded that mass loss rates are considerably lower in O stars than in Of stars, but that if mass loss is really proportional to luminosity, the earliest O stars should have rates at least a factor of 10 higher than were found.
Conti, P. S.↗
Observation of the core of the Perseus cluster with the Einstein solid state spectrometer: Cooling gas and elemental abundances
Solid State Spectrometer observations of the core of the Perseus cluster have resulted in the detection of X-ray emission lines due to Si, S, and Fe. Analysis of the spectrum indicates that the X-ray emission has at least two characteristic temperatures. This is interpreted in the framework of radiative accretion in the core of the cluster. The derived parameters are a cooling time tc less than 2 x 109 yrs for the low temperature gas, a mass accretion rate of approximately 300 Mo/yr and a characteristic size of 10 to 20 Kpc for the cool gas. The Fe abundance in the core, approximately 0.4, is similar to the Fe abundance averaged over the whole cluster indicating that Fe emission is not strongly concentrated about NGC 1275. The Si and S abundances are consistent with solar values.
Mushotzky, R. F.↗
Direct observation of charge state abundances of energetic He, C, O, and Fe emitted in solar flares
The ionic charge states of helium, carbon, oxygen, and iron have been determined for three solar particle enhancements by an electrostatic deflection analyzer, which is combined with a thin window proportional counter dE/dX vs. E system. The observations are obtained during the periods September 23 to 29, 1978, June 6 to 8, 1979, and September 15 to 26, 1979, with an instrument onboard the ISEE-3 spacecraft. The mean ionic charge states for He, C, and oxygen exhibit a high degree of ionization with values of Q equals 2, 6, and 7.2, respectively. The charge state of iron is near 13 charge units. Variations from flare to flare and within the September 23, 1978 flare are small. The most surprising feature of the charge state measurement is the observation of a small (about 10%) but finite contribution of singly ionized helium.
Hovestadt, D.↗
Low-energy hot plasma and particles in Saturn's magnetosphere
Results of the low-energy charged particle experiment carried by Voyager 2 in the Saturn magnetosphere are presented. Measurements of ions of energy greater than 28 keV and electrons of energies greater than 22 keV revealed the presence of a region containing an extremely hot (30-50 keV) plasma extending from the orbit of Tethys past the orbit of Rhea, and a low-energy ion mantle inside the dayside and nightside magnetospheres. H, H2, H3, He, C and O at energies greater than 200 keV/n were found to be important constituents of the Saturn magnetosphere, at relative abundances suggestive of a solar wind origin. Low-energy electron flux enhancements were observed between the L shells of Rhea and Tethys which were absent during the Voyager 1 encounter, and persistent asymmetric electron pitch-angle distributions were noted in the outer magnetosphere in conjunction with the hot ion plasma torus. Signatures of the passage of Tethys and Enceladus through the magnetosphere were found, although not at the positions predicted by dipole magnetic field models.
Krimigis, S. M.↗
The composition of ultra-heavy cosmic rays
Preliminary results on the composition of ultraheavy nuclei in the cosmic rays are now available from experiments on HEAO-3 and Ariel-VI satellites. These results are compared with the composition predicted for reasonable propagation models using source abundances similar to those of solar system material. The effects of varying model parameters and of preferential acceleration are discussed. Discrepancies between predicted and observed abundances are larger than can be accounted for solely by first ionization potential effects and are interpreted in terms of a nucleosynthesis process.
Protheroe, R. J.↗
Mars' global properties - Maps and applications
Mars data sets from many sources have been put into a common digital format and global maps at constant scale have been produced. These formatted data sets form the basis of the Mars Consortium. They currently include maps of geology, volcanic units, channels, wind features, topography, gravity, Viking approach and apoapsis color, predawn temperature residuals, thermal inertia, radiometric and solar albedo, water vapor abundance, 1.4 micrometers albedo, crater abundance, Earth-based radar and photographic telescope observations, and terrestrial spectral observations. The generation of these data sets is briefly described. As an example of their use, the mapped geologic units are characterized in terms of color, predawn temperature and elevation, and unusual areas identified. The Oxia Palus region is examined as an example of combining higher resolution data with the Consortium data sets. Use of the existing data sets and submission of new ones are encouraged.
Kieffer, H. H.↗
Extinct radioactivities - A three-phase mixing model
A new class of models is advanced for interpreting the relationship of radioactive abundances in the early solar system to their average concentration in the interstellar medium. The model assumes that fresh radioactivities are ejected from supernovae into the hot interstellar medium, and that the time scales for changes of phase into molecular clouds determine how much survives for formation therein of the solar system. A more realistic and physically motivated understanding of the low observed concentrations of I-129, Pu-244, and Pd-107 may result.
Clayton, D. D.↗
Saturn meteorology - A diagnostic assessment of thin-layer configurations for the zonal flow
Voyager imaging, infrared, and radio observations for Saturn have been recently interpreted by Smith et al. (1982) as an indication that the jet streams observed at the cloud tops extend to depths greater than the 10,000-bar level. This analysis assumes a maximum latitudinal temperature contrast of a few percent, a mean atmospheric rotation rate at depth given by Saturn's ratio period, and no variation with latitude of the bottom pressure level for the zonal flow system. These assumptions are not, however, firmly constrained by observation. The diagnostic analysis of plausible alternative configurations for Saturn's atmospheric structure demonstrates that a thin weather layer system (confined at mid to high latitudes to levels above 200 bar) cannot be excluded by any of the available observations. A quantitative estimate of the effects of moisture condensation (including the differentiation of mean molecular weight) suggests that these might provide the buoyancy contrasts necessary to support a thin-layer flow provided that Saturn's outer envelope is enriched approximately 10 times in water abundance relative to a solar composition atmosphere and strongly differentiated with latitude at the condensation level.
Allison, M.↗