SEARCH · Search NASA
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.
Limiting distribution of likelihood ratio statistic under class of local alternatives and minimum average risk decision procedures for noncentral chi-square distribution
He 10830 angstrom Fraunhofer line in late type stars determined from spectroscopic stellar observations indicating hot chromospheres existence
IR observations of Crab Nebula using 30 inch aperture telescope
Hydroxyl free radical microwave spectrum definition by doubling transitions frequency predictions, noting radio astronomy applicability
Theoretical and investigation calculations of Venus brightness temperature, and radio emission peculiarities due to presence of moisture in atmosphere
Electrophotometric observations on spatial discontinuities of green atomic oxygen line in airglow spectrum
Spatial distribution and emission intensity of luminescent patches in airglow
Ionospheric effects caused by 2-12 angstrom solar X ray quiescent flux and flare flux
Background radiation intensity upper limits for mm and submillimeter wavelengths in interstellar medium, noting intense flux in far IR
Solar flares less than 10 A X rays effect on ionospheric ionization between 60 and 100 km
Auroral short period pulsations in 6300 A O I, discussing percentage modulation, quenching rate, etc
Spectrum analysis of sulfur beam foil source in ultraviolet region
Measurements of Van der Waals Na 5889 A in He with piston compressor light source
Observations are presented that have been obtained as part of a larger program to accumulate an extensive body of line-profile data for early-type stars with a single system of high photometric precision and low noise. The very good agreement of these data with the predictions of Auer and Mihalas (1972) largely resolves one of the outstanding discrepancies between theory and observation.
Results of measurements of the differential counting rate spectra due to atmospheric gamma rays as a function of altitude to 3.6 g/sq cm over Texas. Two gain settings and a 128-channel pulse height analyzer were used to cover the range from 0.2 to 10 MeV. The detector was a 7.6 x 7.6 cm NaI crystal, which was surrounded on five sides by a 2-cm-thick plastic anticoincidence shield for charged particle rejection. The system had a nearly isotropic response to photons above 0.2 MeV. The spectrum at ceiling appeared as a steep continuum with a power-law index of about 1.4. The only obvious feature was the 0.51-MeV positron annihilation line. The spectral shape was independent for depths less than 20 g/sq cm, the absolute intensity varying in proportion to the intensity of the cosmic ray secondary charged particles. Also, at depths less than 30 g/sq cm the observed flux variation with altitude can be described in terms of an empirical depth-dependent source function.
Explore the source record for details and available documents.
Line profiles were first obtained at maximum velocity separation of the spectroscopic binary Spica (alpha Vir), and then high resolution spectrophotometric images of selected features in the 1.1 micron spectrum of Comet Kohoutek were obtained in order to gain insight into the structures and variations in early-type star atmospheres.
Explore the source record for details and available documents.