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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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At least 181 records · Page 10
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NASA NTRS1971

An upper limit on the hardness of the nonthermal electron spectra produced during the flash phase of solar flares.

The observations of impulsive solar-flare X-rays above 10 keV made with OGO-5 satellite have been analyzed in order to study the variation of the nonthermal electron spectrum from one flare to another. The X-ray spectrum at the maxima of 129 impulsive X-ray bursts is represented by KE to the minus-gamma power photons per sq cm per sec per keV, and the frequency of occurrence of bursts with different values of gamma is studied. It is found that for gamma less than 4.0 the frequency of bursts rapidly decreases with the decrease in the value of gamma. The probability of occurrence of a burst with gamma less than 2.3 is extremely small.

Kane, S. R.↗
NASA NTRS1972

Upper limits to the soft X-ray emission of sources in Virgo.

Discussion of the soft X-rays from Virgo observed with a scanning focusing collector from an Aerobee 170 rocket. The region included the center of the Virgo cluster of galaxies, a source of higher energies which had been previously identified with M87, and QSO 3C 273. No discrete sources in Virgo were observed.

Gorenstein, P.↗
NASA NTRS1972

Upper limits on the atomic hydrogen abundance in 12 globular clusters.

Description of 21-cm neutral-hydrogen line observations of 12 globular clusters performed with negative results by means of the NRAO 140-ft telescope. Limits on the atomic hydrogen content yielded by these observations over a range of 11 to 85 solar masses are presented.-

Kerr, F. J.↗
NASA NTRS1976

The atmosphere of Mars near the surface - Isotope ratios and upper limits on noble gases

Several analyses of the Martian atmosphere have been carried out with the mass spectrometer in the molecular-analysis experiment. The ratios of abundant isotopes of carbon and oxygen are within 10 per cent of terrestrial values, whereas nitrogen-15 is considerably enriched on Mars. Argon-38 has been detected, and new limits on abundances of krypton and xenon have been set. The limit on krypton is sufficiently low to suggest that the inventories of volatile substances on Mars and on earth may be distinctly different.

Biemann, K.↗