Pioneer VI observations of the solar flare particle event of 7 July, 1966.
Time dependency, anisotropy degree and spectral composition of cosmic radiation generated during July 1966 solar flares as observed by Pioneer VI
SOLAR FLARE↗
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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.
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Mean lives of the ip super 2 super 1 D level in F VI and O V.
Mean lives of 1s super 2 2p super 2 super 1D level in F VI and O V measured by beam foil technique
Bashkin, S.↗
C V spectra near the 1s-2p line of C VI
C V lines measured near 1s-2p line of C VI, identifying lines belonging to various transitions
Cohen, L.↗
Analysis of low temperature trapping and recombination in II-VI compounds using photodielectric techniques
Using photodielectric effect to detect densities of free and trapped carriers in II-VI compounds at cryogenic temperatures
Hartwig, W. H.↗
Heterojunctions involving II-VI compound semiconductors
Heterojunctions with II-VI compound semiconductors, evaluating electro-optical performance
Milnes, A. G.↗
Mean lives of excited levels in O I-O VI
Ion beam-foil produced oxygen spectra in wavelength range between 450 and 2200 A, determining mean radiative lives of O I - O VI excitation levels
Berry, H. G.↗
Search for interstellar silicate absorption in spectrum of VI Cyg No. 12
Interstellar silicate absorption search using VI Cyg No 12 spectrum observations
Gillett, F. C.↗
Hourly variations in O VI P Cygni profiles of hot stars
Significant changes in the ultraviolet absorption profiles are reported in the spectra of Delta Ori A, Iota Ori, and Zeta Pup. The present data show changes in count rates in excess of 30 per cent at velocities more negative than -900 km/s, if these data are interpreted as being dominated by O VI absorption in stellar winds. The time scales range from 1 to 6 hours.
York, D. G.↗
O VI gas - Circumstellar or interstellar
Observations in the UV spectra from the Copernicus satellite have revealed absorption lines from five-times ionized oxygen atoms. To explain this abundance, two explanations have been advanced to supplant the traditional model of steady loss from nearby stars. One, ionization from circumstellar bubbles, is said to result from rapidly rotating stars. The other, examined in more detail, suggests a mechanism whereby shock waves from explosive disturbances in nearby supernovae preferentially channel coronal-type O VI regions in the interstellar medium into areas of high temperature (above 100,000 K). An examination of column densities with increasing distribution is proposed to examine the hypotheses, although the results are as yet inconclusive.
Jenkins, E. B.↗
Ultraviolet observations of cool stars. VI - L alpha and Mg II emission line profiles /and a search for flux variability/ in Arcturus
High-precision, high-resolution profiles of the L alpha and Mg II k chromospheric emission lines from Arcturus (alpha Boo) obtained with the Princeton Experimental Package aboard the Copernicus satellite are presented. Asymmetries seen in the profiles of these lines are probably intrinsic to the star, rather than the result of interstellar absorption. In contrast to previous observations of the Ca II K emission line, no evidence is found during a three-year period for variability in the profiles or in the total fluxes from these lines on time scales ranging from hours to months. Also presented is a flux profile of the O I 1302 line and flux upper limits for L beta, O VI 1032, Si III 1206, and O V 1218.
Mcclintock, W.↗
Phase transitions in Group III-V and II-VI semiconductors at high pressure
The structures and transition pressures of Group III-V and II-VI semiconductors and of a pseudobinary system (Ga/x/In/1-x/Sb) have been investigated. Results indicate that GaP, InSb, GaSb, GaAs and possible AlP assume Metallic structures at high pressures; a tetragonal, beta-Sn-like structure is adopted by only InSb and GaSb. The rocksalt phase is preferred in InP, InAs, AlSb, ZnO and ZnS. The model of Van Vechten (1973) gives transition pressures which are in good agreement with measured values, but must be refined to account for the occurrence of the ionic rocksalt structure in some compounds. In addition, discrepancies between the theoretical scaling values for volume changes at the semiconductor-to-metal transitions are observed.
Yu, S. C.↗
Discovery of an X-ray star association in VI Cygni /Cyg OB2/
A group of six X-ray sources located within 0.4 deg of Cygnus X-3 has been discovered with the Einstein Observatory. These sources have been positively identified and five of them correspond to stars in the heavily obscured OB association VI Cygni. The optical counterparts include four of the most luminous O stars within the field of view and a B5 supergiant. These sources are found to have typical X-ray luminosities of 5 x 10 to the 33rd ergs/s, with temperatures of 10 to the 6.8th K and hydrogen column densities of 10 to the 22nd/sq cm, and therefore comprise a new class of low-luminosity galactic X-ray sources associated with early-type stars.
Harnden, F. R., Jr.↗
Brightness profiles of CO/+/ in the ionosphere of Comet West /1976 VI/
The observed sunward and tailward brightness profiles of the (2-0) band of the (A2Pi-X2Sigma) system of CO(+) (4260 A) in Comet West (1976 VI) are established over a range of heliocentric distance from 0.440 to 0.842 AU. From these data the variation with heliocentric distance of the CO(+) production rate is investigated along with the size of the contact surface (the diameter of the onset of the tail). A photoionization model is proposed for the production of CO(+) in Comet West in which CO photoionization is considered to be the principle source of CO(+); the model is consistent with the observational data and the MHD theories.
Combi, M. R.↗
Evidence for fragmentation of strongly nonspherical dust particles in the tail of Comet West 1976 VI
Motion of 16 striae through the dust tail of Comet West 1976 VI are observed over a time interval of more than three days. Initiation times for most of the 16 striae are found to coincide with the times of discrete violent bursts of dust, determined from the motions of streamers. It is also found that fragments are subjected to repulsive accelerations between 0.6 and 2.7 the solar attraction, indicating submicron-size absorbing particles, while repulsive accelerations imparted to parent articles are slightly lower than the average acceleration of fragments. The sizes of the fragments are estimated to be between one tenth and a few tenths of a micron. No effect of the Lorentz force on striae motion is detected. It is concluded that the theoretical assumption that striae are products of fragmentation of friable dust particles ejected from the nucleus agrees with observations.
Sekanina, Z.↗
Optical polarimetry of Comet West 1976 VI
Four narrowband filters covering the 440-850 nm wavelengths were used to measure the polarization of the continuum of Comet West 1976 VI. Postperihelion observations indicated wavelength-independent linear polarization in all of the three measurements made, in agreement with other polarization measurements of the comet from the visible to the near-infrared but in contrast with the general tendency in comets toward polarization increase with wavelength. No circular polarization was detected, and it is suggested by (1) the magnitude of polarization as a function of scattering angle, (2) wavelength independence, and (3) infrared and optical photometric properties, that dirty silicates with radii approaching 5 microns may be responsible for the phenomena observed.
Michalsky, J. J.↗
Search for plasma shifts of C VI, N VII, and O VIII resonance lines
The resonance lines of the hydrogenlike ions C VI, N VII, and O VIII were observed in laser-produced plasmas with electron densities in the range 10 to the 21st - 10 to the 22nd per cu cm and electron temperatures between about 70 and 100 eV. The lines of the hydrogenlike ions were recorded photographically with a 3-m grazing-incidence spectrograph. No significant plasma line shift was observed.
Goldsmith, S.↗
A comparison of the C III, O V, F VI, and Ne VII Delta n = 0 (2-2) line emissions from a laboratory plasma with theoretical predictions and astrophysical observations
Spectra of the Delta n = 0 (2-2) transitions of Be I-like ions, C III, O V, F VI, and Ne VII emitted from the TEXT tokamak, were measured with photometrically calibrated instrumentation and compared to the predictions of several models which differ in their treatment of electron impact excitation, using either the distorted wave or R-matrix approach. It was found that the ions from C III to Ne VII were located near the edge of the plasma, at densities between 10 to the 12th and 13th/cu cm. The experimental line ratios were compared with several sets of computations. Agreement is obtained between the experimental data and computations by using the R-matrix technique. This leads to the conclusion that the effect resonances must be included in collision strength calculations, particularly at low nuclear charge. The results show that the line ratios studied may be used with confidence as electron density diagnostics for laboratory or astrophysical plasmas.
Finkenthal, M.↗
Ballistic transport in II-VI semiconductor compounds and alloys
Realistic band structures are used in calculating the group velocity and scattering rates for electrons with injection energies up to 1 eV in ZnTe, CdTe, and the low-effective-mass alloy Hg(0.7)Cd(0.3)Te. Scattering from longitudinal optical phonons, ionized impurities, and alloy disorder have been included in the full band-structure calculation, which automatically includes both intra- and intervalley scattering. Of the II-VI materials considered, at 77 K HgCdTe is superior for low injection energies (up to 0.25 eV) while CdTe is superior at higher injection energies (1 eV) at room temperature. The attainable mean free paths (equal to or greater than 1000 A) and group velocities (equal to or greater than 10 to the 8th cm/s) for both systems are comparable to values found in III-V systems.
Berding, M. A.↗