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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 1,657 records · Page 92
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

The nature of Becklin's star.

The IR point source in the Orion Nebula commonly known as Becklin's star appears to be exceptional because of its extreme colors and the lack of any associated optical object. Characteristics of the spectrum of Becklin's object are examined. It is found that the spectrum is consistent with that of a highly reddened early-type supergiant, in which weak absorption has been masked by low resolution.

Penston, M. V.↗
NASA NTRS1972

Detection of interstellar recombination lines from emitters of intermediate mass.

The 18-cm microwave spectra of Orion B and W3A show evidence of an emission feature to the high-frequency side of the carbon recombination line. Observations at different frequencies establish that this feature results from electronic recombination. In addition, theoretical considerations, results of 21-cm observations, and computer-simulated spectra suggest that the new feature originates in a predominantly neutral hydrogen region and can be explained by a superposition of recombination lines from any or all of the following elements: Mg-24, Si-28, S-32, and Fe-56.

Chaisson, E. J.↗
NASA NTRS1972

Interstellar organic chemistry.

Most of the interstellar organic molecules have been found in the large radio source Sagittarius B2 toward the galactic center, and in such regions as W51 and the IR source in the Orion nebula. Questions of the reliability of molecular identifications are discussed together with aspects of organic synthesis in condensing clouds, degradational origin, synthesis on grains, UV natural selection, interstellar biology, and contributions to planetary biology.

Sagan, C.↗
NASA NTRS1973

The sulfur doublet in galactic H-II regions

Spectrographic scans for sulfur doublet intensity in the Orion nebula show that electron density decreases from about 15,000 down to about 1500 electrons per cubic centimeter within a few minutes of arc in both directions from the maximum. There appears to be small-scale structure in the electron density, with variations by a factor of two very common. Satisfactory agreement is obtained for electron density values derived from the oxygen doublet as well as from the sulfur doublet.

Mccracken, C. W.↗
NASA NTRS1972

Circular polarimetry of fifteen interesting objects.

The results of a search are presented for circular polarization of visible light in 15 objects, including two eclipsing binaries, six magnetic Ap stars, three planetary nebulae, Hubble's Nebula, M87, Sirius, and the Orion A region. On the whole, the results were null, down to typical upper limits for q of 0.01 per cent. A complete description of the used photoelastic polarimeter is given, with special attention to the incidental linear-circular conversion.

Kemp, J. C.↗
NASA NTRS1973

Astronomical observations with an SEC vidicon system.

Description of the design and operation of an SEC vidicon camera system, and review of some of the astronomical observations performed with it. Following a discussion of the main system and instrumentation features and a delineation of present and future software tasks, the preliminary series of observations obtained in conjunction with the 36-inch telescope at Kitt Peak National Observatory is briefly surveyed. These observations include (1) exposures on the Orion Nebula through various narrow-band interference filters, and (2) exposures on the galaxy Messier 82 in white light and with medium band filters.

Chiu, H.-Y.↗
NASA NTRS1974

Research on infrared astrophysics and X ray and XUV astronomy

The infrared research was divided into two related subjects, observations at wavelengths less than 34 microns and millimeter wavelength observations. A new complex of infrared sources in the Orion Nebula observed along with a broad range of galactic and extragalactic objects. The Comet Kohoutek was measured in the 1-20 micron wavelength region and its thermal properties agreed closely with those of Comet Ikeya-Seki. Combined infrared and photoelectric studies of the Makarian galaxies showed them to have a composite spectrum with a large emission feature in the far infrared. The development of one millimeter photometry and composited bolometers is described. A technique of reconstructing two dimensional surface brightness distributions with appropriate errors from individual strip scans was developed. Model parameters were determined by fitting data in non-linear systems. Results show spectral parameter uncertainties are underestimated or incorrectly evaluated in most studies.

Source record↗
NASA NTRS1973

Observations of diffuse galactic H alpha and forbidden N II emission

A study has been made of the intensities and radial velocities of faint galactic H alpha and forbidden N II 6584-emission lines not associated with any known bright H II regions. Although some (about 10%) of the observed radiation may be scattered galactic light from bright H II regions in the galactic plane, most of the radiation appears to be produced by an ionized component of the interstellar gas which is distributed throughout the interstellar medium within the three nearby galactic spiral arms. In the local Orion arm the emitting gas has a temperature between 3000 and 8000 K and mean square electron density approximately equal to 0.05 cm to the minus 6th power in the galactic plane, while in the Perseus and Sagittarius arms the mean square electron density is equal to about 0.1 and 0.9 cm to the minus 6th power, respectively.

Reynolds, R. J.↗
NASA NTRS1973

Observation of the J = 2 to J = 1 transition of interstellar CO at 1.3 millimeters

The NRAO 36-foot antenna at Kitt Peak with a novel type of millimeter-wave superheterodyne receiver was used in observations of 1.3-mm line interstellar radiation due to J ? 2-1 transitions of C(12)0(16) and C(13)0(16). The liquid-helium-cooled hot-electron bolometer mixer of the superheterodyne receiver was used as the detecting element. The Orion Nebula CO system was found to be thermalized, showing a peak excitation temperature of about 76 K.

Phillips, T. G.↗
NASA NTRS1973

Interstellar oxygen-17

Cases of line emission were observed from the molecular clouds associated with the Orion Nebula and the rho Ophiuchi complex. The emission is attributed to a certain rotational transition of CO consisting of the isotopes C-12 and O-17. This observation signifies the first detection of O-17 outside the solar system. It is pointed out that the relative abundance of O-17 is an important astrophysical quantity because of a possible enrichment during the hot CNO cycle.

Encrenaz, P. J.↗