Electron and local gas densities in diffuse interstellar clouds from measurements of Ca I absorption
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Federman, S. R.↗
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Invalidity of local thermodynamic equilibrium for electrons in the solar transition region. I - Fokker-Planck results
(Previously announced in STAR as N83-17439)
Shoub, E. C.↗
Dependence of radio emission in large H alpha flares 1967-1970 upon the orientation of the local solar magnetic field
Published data on ionizing radiation (as reflected in sudden ionospheric disturbances), H-alpha importance, 10-cm flux, dynamic spectrum, and 200-MHz flux are analyzed for a group of 84 solar flares (from 1967 to 1970) classified by Pudovkin and Chertkov (1976). The group consists of 29 flares with southern orientation of the 100,000-km-scale overlying magnetic field, 32 with northern orientation, and 23 with indeterminate orientation; all have H-alpha importance greater than about 2. Slightly greater X-ray and optical emissions, but one-order-of-magnitude greater prompt 200-MHz and 10-cm fluxes are found in southern as compared to northern-oriented flares. It is inferred that the amount of electromagnetic flare energy radiated promptly from the corona, as compared with that radiated from the chromosphere, was significantly affectly by the orientation of the overlying large-scale magnetic field during the period of observation. This trend is shown to be consistent despite some periodic variation.
Roelof, E. C.↗
Stellar populations in local group dwarf elliptical galaxies. I - NGC 147
A color-magnitude diagram of NGC 147 to an I magnitude of 23 is presented. The stellar population in the outer parts of this elliptical galaxy resembles that of the globular clusters of the Milky Way. Quantitative comparison of the giant branch with those of globular clusters yields a mean metallicity of -1.2 + or - 0.2, making NGC 147 a part of the general correlation between mass and metallicity seen in ellipticals. The giant branch appears to be broad, which suggests a metallicity dispersion. The absence of asymptotic giant branch stars at luminosities above that of the red giant branch tip sets an upper limit of 10 percent for the fraction of stars in this NGC 147 field that have ages less than 12 Gyr. This result contrasts with the situation in some of the related, but less massive, dwarf spheroidal systems. If the choice is made to assume, rather than determine the stellar content of NGC 147, a distance of 630 + or - 50 kpc is derived, similar to that of M31.
Mould, J. R.↗
Deciphering the Local Interstellar Spectra of Secondary Nuclei with the Galprop/Helmod Framework and a Hint for Primary Lithium in Cosmic Rays
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M. J. Boschini↗
Localized blocking accounted for by slow variations of the zonal driving
The incorporation of observed zonal topography in a barotropic nonlinear channel model is discussed. The model is then extended to explain the regional features of blocking by employing a two scale method to allow small slow variations of the momentum (zonal) driving.
Mo, K. C.↗
A semi-direct procedure using a local relaxation factor and its application to an internal flow problem
Generally, fast direct solvers are not directly applicable to a nonseparable elliptic partial differential equation. This limitation, however, is circumvented by a semi-direct procedure, i.e., an iterative procedure using fast direct solvers. An efficient semi-direct procedure which is easy to implement and applicable to a variety of boundary conditions is presented. The current procedure also possesses other highly desirable properties, i.e.: (1) the convergence rate does not decrease with an increase of grid cell aspect ratio, and (2) the convergence rate is estimated using the coefficients of the partial differential equation being solved.
Chang, S. C.↗
Lithification opf gas-rich chondrite regolith breccias by grain boundary and localized shock melting
The fine-grained matrices (less than 150 microns) of 14 gas-rich ordinary chondrile regolith breccias were studied in an attempt to decipher the nature of the lithification process that converted loose regolith material into consolidated breccias. It is found that there is a continuouos gradation in matrix textures from nearly completely clastic (class A) to highly cemented (class C) breccias in which the remining clasts are completely surrounded by interstitial, shock-melted material. It is concluded that this interstitial material is formed by shock melting in the porous regolith. In general, the abundances of solar-wind-implanted He-4 and Ne-20 are inversely correlated with the abundance of intenstitial, shock-melted, feldspathic material. Chondrites with the highest abundance of interstitial, melted material (class C) experienced the highest shock pressures and temperatures and suffered the most extensive degassing. It is this interstitial, feldspathic melt that lithifies and cements the breccias together; those breccias with very little interstitial melt (class A) are the most porous and least consolidated.
Bischoff, A.↗
The affine equivalence of local stress and displacement distributions in damaged composites and Batdorf's electric analog
The composite solid/analog device affine equations are shown to be elastically and electrically material independent. Analog experimental solutions yield the stress and displacement fields of the composite solid for a wide range of physical variables.
Brunelle, E. J.↗
Stellar populations in local group dwarf elliptical galaxies. II - NGC 205
NGC 205, a dwarf elliptical companion of M31, was studied using deep CCD photometry on the VRI system. Consideration is given to a comparison between the giant branch and the Galactic globular clusters, the degree of chemical enrichment in the outer parts of NGC 204, and the setting of constraints on the stellar population of NGC 205. Should the distance of the galaxy be that of M31, this field's stellar population is extremely old. If star formation in NGC 205 is a recurring phenomenon, it is confined to the interior of the galaxy. Should the stellar population of NGC 205 be as old as Galactic globular clusters, its distance modulus is 24.3 + or - 0.2. The giant branch location corresponds to a mean metallicity greater than or equal to -0.9 + or - 0.2, and a metallicity dispersion is determined to be sigma greater than or equal to 0.5 dex. Also noted is that the color distribution at a given luminosity appears to be positively skewed.
Mould, J.↗
Coronal mass ejection recurrence studies indicating global activity and local suppression
The distribution of time intervals between successive coronal mass ejection events observed from the SMM and Skylab coronagraphs has been analyzed. Histograms of such recurrence times show that mass ejections tend to cluster in periods of activity. Evidence is found for simultaneous activity on a global scale. A second result is that, statistically, limb regions within + or - 59 deg position angle of a mass ejection show a marked absence of subsequent observable ejections for approximately 10 h. Flares of importance greater than or equal to 1 show no such deficit; however, large disparitons brusques tend similarly to be suppressed, for 24 h. This result, together with the closer association of mass ejection with eruptive prominences rather than with flares and the realization that eruptive prominences are rarely if ever seen without an accompanying mass ejection, obviates suggestions that magnetohydrodynamic conditions in the outflow following the earlier mass ejection hide subsequent coronal events.
Wagner, W. J.↗
Time history, energy spectrum, and localization of an unusual gamma-ray burst
A gamma-ray burst lasting about 48 ms was observed on June 13, 1979 by four instruments in the interplanetary network. The event is unusual not only by virture of its extremely short duration, but also by the presence of rise and fall times at the 2 ms level in the time history, and because the energy spectrum is hard, extending to 2 MeV. The 0.7 sq arcmin error box contains no optical counterpart on the POSS plate (limiting magnitude, about 21). The spectral characteristics measured by experiments in the interplanetary network are substantially different from those previously reported for this burst.
Barat, C.↗
Atomic mean excitation energies for stopping powers from local plasma oscillator strengths
The stopping of a charged particle by isolated atoms is investigated theoretically using an 'atomic plasma' model in which atomic oscillator strengths are replaced by the plasma frequency spectrum. The plasma-frequency correction factor for individual electron motion proposed by Pines (1953) is incorporated, and atomic mean excitation energies are calculated for atoms through Sr. The results are compared in a graph with those obtained theoretically by Inokuti et al. (1978, 1981) and Dehmer et al. (1975) and with the experimental values compiled by Seltzer and Berger (1982): good agreement is shown.
Wilson, J. W.↗
Cosmic ray propagation in the local superbubble
It is suggested that a ring of HI gas lying in the galactic plane is part of a supershell which formed some 3 x to the 7th power years ago. The consequences of a closed magnetic supershell for cosmic ray propagation are examined and it is concluded that there is no evidence which precludes the production and trapping of cosmic rays in such a region. A consequence of superbubble confinement is that the mean age of cosmic rays would be independent of energy. This can be tested by high energy observations of the isotopic composition of Be.
Steitmatter, R. E.↗
Realistic localizer courses for aircraft instrument landing simulators
The realistic instrument landing simulator (ILS) course structures for use in aircraft simulators are described. Software developed for data conversion and translation of ILS course structure measurements and calcomp plots of the courses provided are described. A method of implementing the ILS course structure data in existing aircraft simulators is outlined. A cockpit used in the lab to review the digitized ILS course structures is displayed.
Murphy, T. A.↗
Local Interstellar Medium. International Astronomical Union Colloquium No. 81
Helium and hydrogen backscattering; ultraviolet and EUV absorption spectra; optical extinction and polarization; hot gases; soft X-ray observations; infrared and millimeter wavelengths; radio wavelengths and theoretical models of the interstellar matter within about 150 parsecs of the Sun were examined.
Kondo, Y.↗
IUE Observations of the Gaseous Component of the Local Interstellar Medium
Discovery of interstellar Ge, Ga, and Kr is reported. Several intercombination lines of Fe 2 are detected. The depletion is most pronounced in Ca, Ti, and V. The highly ionized gas C 4 and Si 4 is not co-extensive with the Si 2 and C 2 gas nor with the O 6 gas. The molecular gas (CO) shows very small velocity dispersion (b approximately 1 km/sec). HD 149404 has the richest interstellar spectrum (except molecules) of all the stars in this study. HD 147889, the heavily obscured star in the Rho Oph cloud, has the strongest interstellar CO spectrum. Noisy nature of the spectra precludes detection of other molecules.
Gilra, D. P.↗
Optical Emission Line Studies and the Warm, Ionized Component of the Local Interstellar Medium
Observations of diffuse, galactic H alpha, N2 lambda 6583, and S2 6716 emission lines provide evidence for a warm (10,000K), primarily ionized component of the interstellar medium distribution throughout the galactic disk. This component of the interstellar gas has an electron density approximately equals 0.1-0.2/cu cm and occupies about 10 to 30% of the interstellar volume. Interstellar H alpha emission near the galactic poles, the dispersion measure of a nearby pulsar, and observations of interstellar gas flowing into the solar system indicate that this ionized component is an important constituent of the interstellar medium in the solar neighborhood. The intensity of the H alpha background at high galactic latitudes implies that this component is maintained by an average hydrogen ionization rate in the vicinity of the Sun of (2-4) x 100,000 s(-1) per square cm of galactic disk. The emission measure is 1.3 to 2.3 cm (-6) pc toward the galactic poles. The sources of this ionization were not identified but may include escaping Lyman continuum radiation from planetary nebulae, hot white dwarfs, and early type stars.
Reynolds, R. J.↗