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  • LUNAR AND PLANETARY EXPLORATION  (726)
  • Life and Medical Sciences  (346)
  • ASTRONOMY  (246)
  • 1995-1999
  • 1980-1984
  • 1975-1979  (1,318)
  • 1976  (1,318)
Collection
Keywords
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Years
  • 1995-1999
  • 1980-1984
  • 1975-1979  (1,318)
Year
  • 1
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    A study of the cosmic sources of hard X-rays (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: An actively-shielded, high-energy X-ray telescope was launched onboard OSO-8 on 21 June 1975. The primary objectives of this experiment are the measurements of the energy spectrum of discrete cosmic X-ray sources in the range 20 keV to 3 MeV and of the temporal variations in the intensity of each source detected with a time resolution of 0.3 msec. This detector provides the highest duty factor and the finest time resolution of any of its kind for observations over a period of up to 10 days. The background spectrum of this detector in orbit was monitored continuously since shortly after launch. The minimum detectable source strength is estimated to be between 10,000 and 100,000 photons/sq-cm-sec keV, limited primary by the effects of induced radioactivity. From 16 July through 18 July 1975, the X-ray binary, Cen X-3, was observed with the hard X-ray telescope.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 739-746
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  • 2
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    Simultaneous X-ray and optical observations of X Persei (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Photoelectric photometry of X Persei was obtained on five out of seven consective nights in January 1975, from the Lick and Leuschner Observatories. The observations yield B = 6.848 + or - 0.002, B-V = 0.139 + or - 0.001, with no strong evidence for variability during the observing run. These are the faintest and bluest photoelectric magnitudes and colors ever reported for X Per; this change apparently occured relatively uniformly during 1973-74 and is reminiscent of behavior last observed in approximately 1900. The suggested association of X Persei with the weak X-ray source 3U 0352+30 raises the possibility of detection of X-ray/optical covariability. On January 21, 1975, 7 hours of data were obtained from both observatories simulataneous with OAO Copernicus X-ray observations of 3U 0352+30. The X-ray data varied during this period by a factor of two, but there is no obviously correspondent optical activity, to a level of 0.02 mag. The optical data are also used to limit to 0.01 mag variations coincident with the X-ray periodicity.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 719-726
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  • 3
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    OSO-8 GSFC results on Cen X-3 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Spectra of Cen X-3 during eclipse, in transition out of eclipse, and during several later phases of the binary orbit were obtained from quick look data of the July 16-25, 1975 observation by the Goddard X-ray spectroscopy experiment on OSO-8. In the high state there was no absorption turn over. Pulsations were present at least to 23 keV. The spectrum at the pulse minimum was flatter above 7 keV than that of the pulse peak. In transition out of eclipse Cen X-3 emerged above a small low energy flux seen during eclipse. The observations appear to indicate absorption by cold and ionized matter and the presence of iron in the companion's atmosphere. Decreased intensities were observed at late phases of some binary orbits in some cases corresponding to dips. Absorption appears although the low energy component remains. Variable features may be interpretable as absorption and emission by iron and possibly other trace elements.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 207-218
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  • 4
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    X-ray spectroscopy with the ANS satellite (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Preliminary results from the Bragg crystal spectrometer on the ANS satellite are given. No significant Si XIII and Si XIV narrow line emission has been detected from Cygnus X-1, -2, or -3.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 49-52
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  • 5
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    OSO-8 observations of Hercules X-1 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The X-ray binary Her X-1 was observed by the GSFC cosmic X-ray detectors aboard OSO-8 between August 26 and September 3, 1975. The results reported are based on quick look tapes which contain less than 10% of the total time spent on source. Spectra were observed during different phases of the binary period including the anomalous low state (dip) in X-ray intensity. The normal high spectra is well represented by a power law with a short cutoff above approximately 25 keV. A significant and varying enhancement in the intensity around 6.7 keV was observed, suggesting the presence of an iron line. Absorption was seen in the spectrum immediately following eclipse. The dip spectrum is found to be considerably flattened. Also spectra are presented for different phases of the pulse period.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 161-168
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  • 6
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    Some features of the X-ray source Cyg X-3 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Data from the Copernicus satellite are presented which show that the 4.8 hour light curve of Cyg X-3 has been relatively stable in period, shape, and amplitude since the observation of the first giant radio outburst in September 1972. A pulse height spectrum of the source obtained by the Ariel 5 satellite in the 1.5 to 26 kev energy band shows convincing evidence for line emission at about 6.5 keV. The strength of this feature varies in phase with the 4.8 hour continuum modulation, but there is no simple long term relation with the mean continuum intensity per 4.8 hour cycle. Evidence is presented which indicates that the average 2-6 kev intensity of Cyg X-3 has been higher by a factor of 3 since the onset of the radio flares.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 255-265
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  • 7
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    OSO-8 observing schedule for X-ray binaries (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Six different instruments on OSO-8 have observed several binary X-ray sources between energies of 0.13 keV and 1 MeV at various times since 21 June 1975. The schedule for these observations is given, as well as the present plan for such future observations through July 1976. Included is the OSO-8 observing schedule for the transient X-ray source A0620-00.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 729-738
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  • 8
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    X-ray observation of 3U 1700-37 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: X-ray observations with Copernicus reveal three categories of flux variability in 3U 1700-37. High amplitude hourly variations are energy independent in the 3-11 keV range while a change in the low energy absorbing column causes variations in flux level on an orbital time scale. This absorption is most severe prior to eclipse ingress, suggesting that the distribution of absorbing material around the X-ray source is asymmetrical with respect to the line of centers of the binary system. The absorbing material may be identical with a high density region inferred from optical observations of HD 153919. In the third category, the maximum source intensity per binary cycle is variable by at least a factor of two between observations. Measurement of the eclipse duration on three occasions indicate that it is significantly less than when observed by Uhuru.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 559-567
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  • 9
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    A review of 3U 1700-37 = HD 153919 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: X-ray, spectroscopic, and photometric data for the source are reviewed briefly. Some points of controversy and difficulty are discussed. The X-ray source 3U 1700-37 is moderately strong (approximately 100 Uhuru counts) and shows a long eclipse, with a period of 3.412 days. The X-rays are attenuated near 0.5 phase, and show a very wide gradual decrease on either side of the total eclipse. The low-energy cutoff is the strongest of all the X-ray binaries. These characteristics are all qualitatively compatible with the optical star's, which represent an extreme in several ways: (1) the primary is an extreme star with large mass outflow through a spherically symmetric stellar wind; (2) it is the hottest of all X-ray binary primaries (with possible exception of Cen X-3); and (3) the mass ratio is very high and the relative separation of the stars is low.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 531-535
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  • 10
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    The nature of the X-ray nova A0620-00 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: A model is presented for the X-ray nova A0620-00. Identification with a nova can be ruled out on two counts. A binary consisting of a late-type subgiant near the Roche lobe, irradiated by an accreting compact companion is shown, however, to be in agreement with all known observations. Photometry of the optical object should be pursued since variability on an approximately eight hour period is expected.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 361-367
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  • 11
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    New results from long-term observations of Cyg X-1 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Observations of Cyg X-1 between October 1974 and July 1975 reveal a persistent 5.6 day modulation of the 3-6 keV X-ray intensity, having a minimum in phase with superior conjunction of the HDE 226868 binary system. The modulation is found to be most pronounced just prior to the April-May 1975 increase of Cyg X-1, after which both the modulation and intensity are at their lowest values for the entire duration of the observations. These data imply that the X-ray emission from Cyg X-1 arises from the compact member of HDE 226868, and that the increase of April-May 1975 may have represented the depletion of accreting material which had not yet been mixed into a cylindrically symmetric accretion disk about the compact member.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 391-405
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  • 12
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    The interpretation of optical light variations of Centaurus X-3 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The interpretation of optical light variations of X-ray binaries is discussed for the case of negligible reflection effect. The limiting cases of synchronous rotation of the visible star (Roche configuration) and of no rotation (pure tidal deformation) are considered. The theoretical results are compared with the available light curves of Cen X-3. X-ray data of the Copernicus satellite are used to get an impression of the atmospheric structure of the outer layers of the visible component. It is shown, that the X-ray eclipse duration is in good agreement with the mass ration derived from the optical variations. The X-ray eclipse duration is discussed with respect to the extended low states, and a possible correlation of the extended lows with the appearance of the optical light curves is considered.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 179-185
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  • 13
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    The observation program for the GSFC cosmic X-ray spectroscopy experiment (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The cosmic X-ray spectroscopy experiment on OSO-8 will observe seven X-ray binary sources in its first six months of operation. If possible, each of these sources will be observed for one or more binary orbits so that the X-ray spectrum of each object can be observed through all phases of its orbit. For the two pulsing binaries, Her X-1 and Cen X-3, spectral variations over the pulse period will be studied. Simultaneous radio observations of Cyg X-1 and Cyg X-3 will search for any correlation between radio and X-ray emission. During the first year of operation, the detectors will observe over 50% of the known X-ray sources.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 737-738
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  • 14
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    Spectrophotometry of the unusual optical candidate for 3U 1728-24 (=GX 2+5 = GX 1+4) a recurrent nova? (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The spectrum of the object suggested as a possible optical counterpart of GX 2+5, was studied, using the image tube scanner attached to the 3-m telescope of Lick Observatory. An improved X-ray error box obtained with Copernicus strongly supports this proposed identification. The candidate displays all the characteristics of the symbiotic stars and the related recurrent novae. The spectrum reveals the presence of an M star together with a blue component and a large number of emission lines displaying a wide range of ionization. There is evidence of variability of both the continuum and the line intensities. This object provides strong support for the often proposed association of some X-ray sources with nova-like systems.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 691-701
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  • 15
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    Long term X-ray studies of Sco X-1 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: No modulation of the 3-6 keV X-ray intensity of Sco X-1 at a level of excess of 1% is observed at the optical period of .787313d. Evidence is found for shot-noise character in a large fraction or the X-ray emission. Almost all of the Sco X-1 emission can be synthesized in terms of approximately 200 shots per day, each with a duration of approximately 1/3 day.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 703-716
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  • 16
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    The X-ray binary HD 77581 + 3U 0900-40 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The properties of the binary system in the different regions of the electromagnetic spectrum are presented from X-rays to the radio. Physical parameters and a model for the system are derived.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 575-614
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  • 17
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    The Skylab S019 ultraviolet spectra of HD 153919 (=3U 1700-37) and HDE 226868 (=Cyg X-1) (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Ultraviolet spectra of HD153919 (=3U1700-37) and HDE226868 (=Cyg X-1) were obtained with the ultraviolet objective-prism spectrograph of Skylab Experiment S019. The data consist of unwidened spectra which extend to 1,600A for HD153919 and to 2,400A for HDE226868. The wavelength resolution is about 2A to 1,400A and 12A at 2,000A. For HD153919, an unwidened spectrum of fair quality and extending to a wavelength of 1,600A was obtained at 22 sup h 08 sup m on 1 September 1973. The energy distribution in this spectrum generally resembles that of other reddened O stars. A break in continuum intensity seems to occur at a wavelength of about 1,720A. There is a suggestion of an emission line on the longward edge of the break but this could be either a chance clumping of grains or else a photographic edge-effect caused by the break.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 551-553
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  • 18
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    High resolution measurements of Cyg X-1 from rockets (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Cyg X-1 was observed on two occasions (Oct. 4, 1973 and Oct. 3, 1974) by the Goddard X-ray rocket payload. This payload consisted of two gas proportional counters (xenon-methane with 710 sq cm and argon-methane with 610 sq cm using the same 128 channel pulse height analyzer and having 320 micro sec temporal resolution on the 1973 flight and 160 micro sec resolution on the 1974 flight. During both flights, bursts of 1 ms duration were observed with very high statistical certainty. To date all 13 of these bursts were analyzed for spectral and temporal character, and the results of this analysis are presented. The spectra of overall X-ray emission from both flights is also presented. In a source known for its variability, it is remarkable that the spectra taken one year apart are virtually identical.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 443-451
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  • 19
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    The early light curve of A0620-00 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The Ariel-5 All-Sky Monitor measured the 3-6 keV X-ray intensity of 0620-00 for two days shortly after peak emission in August 1975, and continuously throughout September 1975. The effective exposure each day for this source (and every other source in the 80% of the celestial sphere covered by the monitor) is approximately 250 sq cm sec. The light curve obtained through October 1 (when the spin axis was again pointed to A0620-00) is shown. The intensity difference at maximum is obviously a manifestation of the very soft spectrum of the source. Clearly, A0620-00 was approximately four times as bright as Sco X-1 at maximum in the band 3-6 keV. The decay is quite smooth, but cannot be fit with a single e-folding time. The interval between the early All-Sky Monitor points and the onset of continuous coverage has an inferred e-folding time of 22 days, but it is continually increasing throughout September. A0620-00 is apparently similar in its X-ray character to the very strong, long-lasting transient X-ray sources which presently number six. In contrast, only three can be sensibly reconciled with the lower-intensity, shorter-duration hard-spectrum transients which have been found to pulse on a time scale of minutes.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 311-316
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  • 20
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    Absence of iron line emission in Cyg X-3 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: An observation of Cygnus X-3 was made with soft X-ray detectors launched on an Aerobee rocket. The iron line emission observed one month later and in May 1975 was not found. A 3 sigma upper limit for this feature is 0.006 ph/2 cm/s.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 285-292
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  • 21
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    The radio sources associated with Cyg X-3 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Some of the conclusions derived from the data on the radio flaring of Cyg X-3 are summarized. In addition, recent data showing that Cyg X-3 has both active and quiet radio behavior are presented.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 233-244
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  • 22
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    Recent Uhuru results on Centaurus X-3 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The current status of the analysis of Cen X-3 data from Uhuru concerning pulsations, orbital period and eccentricity, and extended lows, are reviewed. The pulse period decreases irregularly. The pulsed fraction (2-7 keV) is 70%-90% for single pulses but significantly less for superpositions of pulses, due to variability in shape. The pulses are narrower at higher energies with a correlated increase in fraction pulsed. The orbital period is found to both decrease and increase with p/p on the order of a few times 0.00001/year. A three sigma upper limit on the eccentricity of 0.003 is obtained; if no significant periastron motion is allowed over two years, the upper limit becomes 0.0016. The orbital period is found to be detectable during some extended lows but with a significantly decreased ratio of eclipsed to non-eclipsed intensity. Two transitions between normal high states and extended lows are studied, and a consistent model is obtained in which extended lows are caused by both burying the source in an increased stellar wind from the companion, and starving the source by decreasing the stellar wind. Changes in fraction pulsed during transitions and systematic differences in the harmonic content of the pulses are also found.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 197-206
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  • 23
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    Optical observations of HDE 226868 = Cygnus X-1: A review (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The present state of knowledge of the binary system HDE226868 = Cygnus X-1 is summarized, including system dimensions, nature of the secondary X-ray source, and mass transfer properties. Some deficiencies in the optical observations are pointed out; these deficiencies make interpretation of the system difficult, but can be corrected.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 465-484
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  • 24
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    Intensity and spectral variations of Cyg X-1 observed from balloons (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Observations of Cyg X-1 with a 20 to 200 keV balloon carried X-ray telescope in 1969, 1970, and 1972 are presented. These results reveal the following characteristics of Cyg X-1: The steep spectrum observed at E 10 keV during the radio quiet phase can extend to 200 keV. This phase may have lasted 21 months (July 1969 to March 1971). The low flux values are factors of 3 and 8 below the normal values at 30 and 100 keV respectively, are rarely observed, and may be associated with the early phase of the 1971 April X-ray transition. During some one hour periods, the intensity remained constant to approximately 20% and during other periods it varied a factor 2 in 5 minutes and a factor 10 in 1 hour. Complex spectral variations accompanied the intensity changes.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 407-424
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  • 25
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    Introduction to Cyg X-1 X-ray panel (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The status of X-ray observations is summarized in tabular form along with general aspects of X-ray emission. Specific questions that arise when the observed phenomena are pieced together into a coherent picture are presented. Spectral states, transitions, periodic behavior, fluctuations, and bursts are among the topics discussed.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 369-372
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  • 26
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    The transient X-ray source A0620-00 (Nova Monocerotis 1975) (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: A0620-00 is the first of the so-called X-ray novae to be identified with an optical object. Emission in the ultraviolet, infrared, and radio wavelength regions was observed from this source. From the observed properties of the optical radiation, it is suggested that the source is a recurrent nova.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 293-309
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  • 27
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    Pulsed X-ray observations of Cen X-3 from Ariel-5 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The 4.8 second X-ray pulsations from Centaurus X-3 were monitored by the MSSL collimated proportional counter on board Ariel-5 between 18-27 January 1975. Analysis of the source Doppler effect shows that the pulsation period of Cen X-3 decreased by 3.70 + or - 0.04 milliseconds during the preceding 2.3 years. The Doppler analysis also yields updated values for the binary phase and period of Cen X-3. Phase zero occurred at JD 2442438.628 + or - 0.003, and the average heliocentric binary period between October 1972 and January 1975 was 2.087129 + or - 0.000007 days. Light curves of the 4.8 second pulsations in the 3-9 keV band are characterized by two pronounced peaks, in contrast with the single peak profiles observed by Uhuru.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 219-231
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  • 28
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    The interstellar matter column density to Cen X-3 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The usual gas-to-dust ratio is shown to hold quite precisely for a sample of supernova remnants with available X-ray spectra and interstellar reddening observations. Supernova remnants are extended objects, tenuous enough to be optically thin in the X-ray range; it is shown that the X-ray observations can readily be interpreted in terms of a main source component and of an interstellar perturbation affecting the lower part of the spectrum. Cen X-3 is associated with an OB supergiant. The effect of the column density is easily detectable in the X-ray range. The spectrum exhibits a low energy cut-off, which is parameterized by a column of cold matter, NX. The cut-off is definitely observed to be variable. There is a suggestion that sometimes NX NH. It is concluded that on those occasions a spurious soft X-ray component is present in the source, bearing close similarity with Cyg X-1.
    Keywords: ASTRONOMY
    Type: X-ray Binaries; p 189-195
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  • 29
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    Radiation mechanisms and magnetospheric structure of pulsars (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A model of pulsars is outlined. Key early considerations were those which led to the identification of pulsars with neutron stars, the Goldreich-Julian model of pulsar magnetospheres, and the recognition that, in a pulsar magnetosphere, a high energy gamma ray may annihilate to produce an electron-positron pair. Arguments that suggest that pulsar magnetospheres may contain large masses of plasma, a suggestion which has important implications concerning the structure of the magnetosphere, are considered along with observational data which support a magnetosphere model based on that idea rather than the Goldreich-Julian model.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 108-117
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    Galactic distribution of pulsars (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The density distributions of pulsars in luminosity, period, Z-distance, and galactocentric distance were derived using a uniform sample of pulsars detected during a 408 MHz pulsar survey at Jodrell Bank. There are indications of a fine scale structure in the spatial distribution and evidence that there is a general correlation with other galactic populations and the overall spiral structure. The electron layer in the galaxy is shown to be wider than the pulsar layer and uniform on a large scale. The number of pulsars in the galaxy was estimated and used to derive the pulsar birthrate.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 299-319
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    Gamma ray pulsars (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Recent data from the high energy gamma ray experiment have revealed the existence of four pulsars emitting photons above 35 MeV. An attempt is made to explain the gamma ray emission from these pulsars in terms of an electron-photon cascade that develops in the magnetosphere of the pulsar. Although there is very little material above the surface of the pulsar, the very intense magnetic fields correspond to many radiation lengths which cause electrons to emit photons via magnetic bremsstrahlung and these photons to pair produce. The cascade develops until the mean photon energy drops below the pair production threshold which happens to be in the gamma ray range; at this stage the photons break out from the source.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 118-127
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    Optical observation of WRA 977 (3U 1233-62?) (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: UBV photometry of WRA 977 on 36 nights between January and July of 1974 shows that this object is active on a time scale of days at the 0.1 mag level, but that it remains quite constant during monitoring intervals lasting up to 1 hour. Periodogram analysis reveals no significant periodic variation in the brightness of this object.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 677-682
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    He II lambda 4686 photometry of HD 153919 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The optical component of the binary X-ray source 3U1700-37/HD 153919 was observed with the interference filter centered on the He II lambda 4686 emission. This photometry does not reveal any dependence of lambda 4686 emission on the orbital phase thereby confirming earlier spectroscopic result that the region of formation of the ionized helium emission is confined to the envelope of the 06f primary.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 555-557
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    Blue band photometry of Cygnus X-1 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Results of blue band photometry of HDE 226868 in the years 1972-3-4 and provisional results for 1975 are presented. A mean light curve is obtained from the first three years observations which is based on 192 nights observations. Intercomparison of the results from the different years shows that the light curve is not constant.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 521-527
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    A0620-00 as a recurrent nova (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Evidence for and against the star associated with A0620-00 being a nova is presented. The conclusion is that this star closely resembles other recurrent novae with the only unusual characteristic being the apparent high temperature at maximum brightness.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 335-341
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    Optical identification of A0620-00 (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Identification of the optical counterpart to the transient X-ray source A0620-00 was made using image tube photography. Spectra taken subsequent to the identification showed no stellar absorption or emission features. Photometric data gave a V magnitude of 11.2 + or - .1. This is about 8 magnitudes brighter than the object appears on the Palomar Sky Survey.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 327-333
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    Observations of Cygnus X-3 by ANS (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The hard X-ray experiment (1 - 28 keV) on ANS observed Cygnus X-3 in November 1974, and in May 1975. The average flux intensities for these time periods were found to be 22.4 + or - 0.5 cts/sec and 12.8 + or - 0.3 cts/sec (1.3 - 7.1 keV), the former being the highest average value ever observed. The spectrum studies show an excess in the flux above the fitted continuum which can be interpreted as a line emission of FeXXIV and/or FeXXV, at approximately 6.5 keV. The strength of this feature varied in phase with the 4.8 hr X-ray modulation, and remained at a constant relative intensity. The period of the X-ray modulation is refined to 0.1996813 + or - 0.0000006 day and obtained at a 2 sigma upper limit to a continuous change in the period of 50 to the minus 13th power/sec. This new limit places serious constraints on several models for this object.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 267-275
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    Copernicus observations of a number of galactic X-ray sources (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: The Copernicus satellite was launched on 21 August 1972. The main experiment on board is the University of Princeton UV telescope. In addition a cosmic X-ray package of somewhat modest aperture was provided by the Mullard Space Science Laboratory (MSSL) of University College London. Following a brief description of the instrument, a list of galactic sources observed during the year is presented. Although the X-ray detection aperture is small, the ability to point the satellite for long periods of time with high accuracy makes Copernicus an ideal vehicle for the study of variable sources.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 1-25
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    Centaurus X-3: The observational picture (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Observations of Centaurus X-3 are briefly reviewed. The composition of the neutron star, optical light curves, and X-ray pulsations are among the topics discussed.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 173-176
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    Periodic flickering in the optical spectrum of HZ Herculis (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: Photometric observations of HZ Herculis in the ultraviolet with a time resolution of 5 seconds are discussed. The existence of periodic flickering with a time scale of 115 to 130 seconds is observed. The amplitude modulation is about 3 to 6 percent, larger than that associated with the erratic white flickering. The flickering, either erratic or periodic, occurs, but not always, near orbital phase 0.5, irrespective of the on and off parts of the X-ray cycle.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 101-111
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    ANS results on X-ray binaries (1976)
    In:  CASI
    Details
    Publication Date: 2006-04-18
    Description: A short description is given of the Astronomical Netherlands Satellite (ANS) and the X-ray instruments of the Space Research Laboratory in Utrecht. The ANS observed in February 1975 a soft (1/4 keV) X-ray flux in Her X-1 during the 'off'-state with an intensity of a factor 10 lower than observed in the 'on'-state. The ANS observations on Cyg X-1 are summarized. During the May 1975 flaring state a very high intensity at 0.5 keV is measured consistent with a power-law photon-spectrum with index 3.5 and an interstellar absorption of 7.10 to the 21st power atoms/sq cm, but not consistent with spectra that show an additional cut-off below 1 KeV and an absorption of 7.10 to the 21st power atoms/sq cm. Intensity changes on a time scale of minutes, as observed in Cyg X-1 low state, are not observed during the flaring state.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Binaries; p 27-47
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    The NASA-NMSU automated meteor observatory (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A new observatory for meteor research which provides data for study of meteor heights, velocities, orbits, and meteoroid abundances is described. The observing equipment is automated to take advantage of the long periods of favorable observing weather common to the region. Four K-24 cameras, electrically operated, provide the triangulation observations, and four Maksutov f/1.3 cameras with blazed transmission grating provide spectral coverage. The patrol cameras have operated for a year and a half, and approximately 6,000 frames have been exposed by 9 March 1975. Meteor trails appear on 260 of these frames. Sixty-eight trails are of meteors photographed from two locations and thus allow trajectory and orbit determinations for 34 meteors. Photoelectric sensors initiate the 2-second spectrograph exposures, and electrical controls open and close the observatory at present times.
    Keywords: ASTRONOMY
    Type: N. Mex. State Univ. Contrib. of the Observatory of N. Mex. State Univ., Vol 1, No. 4; p 166-173
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    Photometry of R Coronae Borealis (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Visual and photoelectric observations of R Coronae Borealis are presented, including a number of observations surrounding the 1974 minimum. The recent visual history of the variable is examined and the discrete cloud obscuration model is considered.
    Keywords: ASTRONOMY
    Type: Contrib. of the Observatory of N. Mex. State Univ., Vol. 1, No. 4; p 134-139
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    Intermediate-band photometry of faint standard stars (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The David Dunlap Observatory system uses six intermediate-band filters whose central wavelengths were chosen to cover important features in the spectrum of a late-type star. Calibrations of the color indices with physical parameters, allow one to estimate T sub eff, log g, Fe/H, M sub v and reddening directly from the photometry. Although a number of standards lists exist, only a small fraction of the stars is fainter than V=6. It is desirable to add to the numbers of faint standards. Results are presented of photometry of sixteen stars obtained during a program of variable-star photometry at Blue Mesa Observatory.
    Keywords: ASTRONOMY
    Type: Contrib. of the Observatory of N. Mex. State Univ., Vol. 1, No. 4; p 140-142
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    Linearization of dynamical systems using integrals of the motion (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A method is presented which transforms certain nonlinear differential equations of dynamics into linear equations by introducing an independent variable and utilizing the integrals of motion. As examples of special interest, the linearizations of unperturbed and perturbed Keplerian motions are discussed.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 14; Dec. 197
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    On the stability of the solutions of the general problem of three bodies (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The extent through which the initial conditions of a given three-body system may be varied without completely changing the qualitative nature of the subsequent system evolution is investigated. It is assumed that the three masses are equal, all initial velocities are zero, the first two bodies initially lie on the x-axis, and the position of the third body is confined to a specific region of space. Analysis of the system evolution for different initial positions of the third body shows that there is a whole area or 'island' in the x-y plane throughout which the initial position of the third body may be moved in a continuous fashion to produce an evolution which also changes in a continuous manner. A Monte Carlo approach is adopted to determine the full extent of this island in the general problem. It is concluded that the stability of a full solution may be directly related to the size of its island in phase space.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 14; Dec. 197
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    Exploration of the giant planets by infrared spectroscopy (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The infrared spectrometer and radiometer for the Mariner-Jupiter-Saturn mission is described. Results of Nimbus and Mariner 9 IR spectroscopy of earth and Mars are used as examples to demonstrate the power and diversity of the technique. Determinations of planetary surface compositions, surface temperatures, vertical temperature profiles, surface pressures, and atmospheric constituents are summarized. Applications to Jupiter and Saturn are briefly mentioned.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    The elimination of short and intermediate period terms from the problem of a high altitude earth satellite (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Delaunay-Similar elements of Scheifele (1976) are applied to the problem of an earth satellite that is perturbed by the sun, moon, and J2. All three effects are assumed to be the same order of magnitude. Since the external body terms depend explicitly on time, the time element appears as an additional angle variable. Also, the eccentric anomaly is used as a noncanonical auxiliary variable. A solution to the first Von Zeipel equation allows simultaneous elimination of short- and intermediate-period terms. The canonical transformation to mean elements is defined by a generating function that is a series involving Bessel coefficients.
    Keywords: ASTRONOMY
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    Structure of Mars' atmosphere up to 100 kilometers from the entry measurements of Viking 2 (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Viking 2 entry data on the structure of Mars' atmosphere up to 100 kilometers define a morning atmosphere with an isothermal region near the surface; a surface pressure 10% greater than that recorded simultaneously at the Viking 1 site; and a thermal structure to 100 kilometers at least qualitatively consistent with pre-Viking modeling of thermal tides. The temperature profile exhibits waves whose amplitude grows with altitude, to about 25 K at 90 kilometers. The atmosphere is stable against convection, except possibly in some very local regions. Temperature is everywhere appreciably above the carbon dioxide condensation boundary at both landing sites, precluding the occurrence of carbon dioxide hazes in northern summer at latitudes to at least 50 deg N. Thus, ground-level mists seen in these latitudes would appear to be condensed water vapor.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Dec. 17
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    Scientific results of the Viking missions (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The two Viking missions to Mars have been extraordinarily successful. Thirteen scientific investigations yielded information about the atmosphere and surface. Two orbiters and landers operating for several months photographed the surface extensively from 1500 kilometers and directly on the surface. Measurements were made of the atmospheric composition, the surface elemental abundance, the atmospheric water vapor, temperature of the surface, and meteorological conditions; direct tests were made for organic material and living organisms. The question of life on Mars remains unanswered. The Viking spacecraft are designed to continue the investigations for at least one Mars year.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Dec. 17
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    Comet West and the scattering function of cometary dust (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Observations of Comet West (1975n) at wavelengths from 0.5 to 18 microns and at a variety of scattering angles are used to infer the scattering phase function for the cometary dust. This function is strongly peaked in the forward direction. The form of the function indicates that the particles are dielectric grains with radii of approximately 1 micron. Abrupt increases in the intrinsic brightness of the coma (both in scattered sunlight and in thermal emission) are consistent with the projected times of comet fragmentation.
    Keywords: ASTRONOMY
    Type: Science; 194; Dec. 3
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    Estimated grain saltation in a Martian atmosphere (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Mariner 9 spacecraft images showing evidence of variable surface features and surface erosion resulting from atmospheric wind on Mars have caused a renewed interest in the eolian mechanics of saltating grains. To study this phenomenon, both experimental investigation in an atmospheric wind tunnel and numerical solutions of the equations of motion of a single grain under Martian surface conditions were conducted. The numerical solutions for earth were used and empirically adjusted to correlate with existing experimental data for Mars. These modified equations were then solved to estimate grain motion for Mars. These calculations show the importance of a lifting force on the grain to initiate motion in both earth and Mars calculations. Major findings include a comparison of earth and Mars grain trajectories that show Mars length scales to be longer and to fall with a higher terminal grain velocity. The grains in the Mars calculation also made a smaller collision angle with the surface on rebound.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 81; Nov. 10
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    Al-26 in Kenna and other ureilites (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A description is presented of the results of a nondestructive analysis conducted with a 42-g slice of the Kenna ureilite. The sample was analyzed in a gamma-gamma coincidence counting system, using a dual-parameter, 4096-channel pulse height analyzer. Data concerning Al-26 and Ne-22/Ne-21 in ureilites and Chassigny are presented in a table. A graph shows the ratio of measured Al-26 activity to that calculated from elemental production rates vs spallation Ne-22/Ne-21 for ureilites and Chassigny. The significance of the data with respect to findings reported by Wilkening et al. (1973) is discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta; 40; Dec. 197
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    Interference in astronomical speckle patterns (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Astronomical speckle patterns are examined in an atmospheric-optics context in order to determine what kind of image quality is to be expected from several different imaging techniques. The model used to describe the instantaneous complex field distribution across the pupil of a large telescope regards the pupil as a deep phase grating with a periodicity given by the size of the cell of uniform phase or the refractive index structure function. This model is used along with an empirical formula derived purely from the physical appearance of the speckle patterns to discuss the orders of interference in astronomical speckle patterns.
    Keywords: ASTRONOMY
    Type: Optical Society of America; vol. 66
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    On the energy deposition of photoelectrons in the atmosphere of Venus (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Vertical components of photoelectron fluxes in the atmosphere of Venus are computed by solving an appropriate form of the Boltzmann equation in the cases where there is no flux of either photoelectrons or solar-wind particles across the ionopause and where photoelectrons are free to escape from the atmosphere. It is assumed that Venus has no magnetic field and that the atmosphere is composed of carbon dioxide, atomic oxygen, and helium. The results are plotted as a function of altitude for several energies in the range from 100 eV to a cutoff of the order of 1 eV. Heating rates for the two upper boundary conditions and the case of no spatial transport are determined which show that transport effects dominate at altitudes greater than about 200 km. Electron temperatures are calculated for the adopted model atmosphere and ionosphere by solving the pertinent conservation equation, and excitation rates are computed for the CO Cameron band as well as the CO2(+) A and B bands.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 81; Oct. 1
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    The 'soil' of Mars /Viking 1/ (1976)
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    Publication Date: 2011-08-16
    Description: The immediate environs of the Viking 1 lander are described, and the techniques employed to deduce the properties of the two different 'soil' types there are summarized. It is shown that the surface in the immediate vicinity of the lander consists of an area with fine-grained materials ('Sandy Flats') and a rocky area set in a matrix of finer-grained material ('Rocky Flats'). Estimates are given for the bulk density, particle density, particle size distribution, cohesion, angle of internal friction, and penetration resistance of the surface layer in each area. Footpad penetration into the surface layer is discussed, and wind removal of particles is examined. It is concluded that the surface layer of the Viking 1 landing site contains loess, dune sand, lunar nominal soil, lag gravel, and bare rock.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Oct. 1
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    Status of the Viking missions (1976)
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    Publication Date: 2011-08-16
    Description: A chronology of Viking 1 lander activities is presented for the first 43 sols (Martian days) of surface sampling and analysis. The orbital insertion of the second Viking spacecraft is reviewed along with the search for the second landing site. A general assessment of the planet is made on the basis of the data thus far obtained. Some of the findings reported are that: (1) there is extensive evidence of volcanism, fluvial and aeolian erosion, and deposition over the entire surface; (2) the floor of Vallis Marineris is significantly younger than the planet's surface; (3) the morphology of Martian crater ejecta is indicative of surface flow rather than ballistic deposition; (4) the rocks in the immediate vicinity of the lander are all covered by a layer of fine red dust; (5) the atmosphere is optically thick and well mixed, with suspended particles giving the sky a pink color; (6) the N and Ar isotopic ratios are different from those on earth; (7) atmospheric water vapor varies with both time of day and location; (8) the summer northern polar regions have a high water concentration in the atmosphere; (9) a large fraction of magnetic material resides in the surface; and (10) no complex organic compounds have been detected in the two samples analyzed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Oct. 1
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    Venus' night side ionosphere - Its origin and maintenance (1976)
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    Publication Date: 2011-08-16
    Description: A substantial nightside ionosphere has been observed on Venus by both Mariner 5 and Mariner 10. Major dayside ionic species such as O2(+) and other molecular ions have chemical lifetimes much shorter than the 244.3-day rotation period of the planet. Rapid transport of ions from the dayside to the nightside to the extent required seems most unlikely. Consequently, possibilities are investigated for local production of ions on the nightside itself. Constraints imposed by chemical lifetimes require atomic ions with low ionization potentials. It is suggested that metallic ions of meteoric origin are the positive charge carriers, and the plausibility of this mechanism is demonstrated. Other possibilities are examined and shown to be less likely. Meteor ablation on Venus, the aeronomy of metallic species, and the role of negative ions near the electron peaks of the atmosphere are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 81; Sept. 1
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    Direct photography of the Gum Nebula (1976)
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    Publication Date: 2011-08-16
    Description: The paper discusses a series of wide-angle photographs taken of the Gum Nebula in the traditional region including H-alpha with the aid of a 40-cm and an 80-cm lens in both the red and the green. The photographs support the large dimensions (75 deg in galactic longitude by 40 deg in galactic latitude) of the Gum Nebula suggested earlier, and the appearance is consistent with an origin due to photons from a supernova outburst. The relatively high-density gas has cooled and is visible on the red plates. The low-density gas has remained at a high temperature and may be visible as diffuse emission on the green plates.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; 208; Aug. 15
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    The Viking landing sites - Selection and certification (1976)
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    Publication Date: 2011-08-16
    Description: During the past several years the Viking project developed plans to use Viking orbiter instruments and earth-based radar to certify the suitability of the landing sites selected as the safest and most scientifically rewarding using Mariner 9 data. During June and July 1976, the earth-based radar and orbital spacecraft observations of some of the prime and backup sites were completed. The results of these combined observations indicated that the Viking 1 prime landing area in the Chryse region of Mars is geologically varied and possibly more hazardous than expected, and was not certifiable as a site for the Viking 1 landing. Consequently, the site certification effort had to be drastically modified and lengthened to search for a site that might be safe enough to attempt to land. The selected site considered at 47.5 deg W, 22.4 deg N represented a compromise between desirable characteristics observed with visual images and those inferred from earth-based radar. It lies in the Chryse region about 900 kilometers northwest of the original site.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 193; Aug. 27
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    The Halley rendezvous via solar sailing mission description (1976)
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    Publication Date: 2011-08-18
    Description: The possibility of using solar sails to achieve a rendezvous with Halley's Comet is explored. Rendezvous trajectories are calculated.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Proc. of the Shuttle-Based Cometary Sci. Workshop; p 251-256
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    QH observations (1976)
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    Publication Date: 2011-08-18
    Description: A model of the dissociative lifetime of the hydroxyl radical is computed where the H2O and OH velocities are vectorially added. A lifetime of approximately 3 x 100,000 seconds is determined.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA. Marshall Space Flight Center Proc. of the Shuttle-Based Cometary Sci. Workshop; p 222-226
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    High resolution spectral analysis of the Jovian decametric radiation. II - The band-like emissions (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Analysis of the bandlike Jovian decametric emission is presented. A model for the active region that accounts for the observed radiation characteristics is described using the measured parameters of the bandlike emission and a model of the Jovian magnetic field. The active region is characterized not only by the fact that an upward-flowing electron stream is caused to radiate in this region, but the stream itself is broken into radiating electron bunches within the active region. Observed undulations of the emission band on the time-frequency plane are interpreted as motions of the active region along a flux tube. The instantaneous location of the active region along the flux tube shows a dependence on the density of the stream entering the active region. The mechanism responsible for density modulation of the stream appears to be common to both the bandlike and simple-S-burst emission types.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 29; Dec. 197
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    High resolution spectral analyses of the Jovian decametric radiation. I - Burst morphology and drift rates (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Morphological analyses of high-resolution spectral recordings of Jovian decametric radiation show a regime of phenomena not seen at lower resolutions. Observed emissions range from narrow-band (50 kHz) simple quasi-periodic bursts to wide-band emissions (extending over a 500-kHz passband) exhibiting complex structural detail. Assuming gyroemission from electrons in a dipole field for which the magnetic moment is 10 Gauss Jupiter-radius-cubed, drift-rate measurements of the bursts indicate that the source size is of the order of 600 km and its location is near 1.3 Jupiter radii at a colatitude of 27.3 deg. The measurements suggest that the emitting electrons belong to a population having a very specific equatorial pitch angle near 3.5 deg. This study concludes that it may be possible to verify gyroemission as the mechanism responsible for the decametric radiation.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 29; Dec. 197
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    The occultation of Mariner 10 by Mercury (1976)
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    Publication Date: 2011-08-17
    Description: Analysis of Mariner 10 dual-frequency radio-occultation recordings has yielded new information on the radius and atmosphere of Mercury. The ingress measurements, which were conducted near 1.1 deg north latitude and 67.4 deg east longitude on the night side of the planet, gave a value for the radius of 2439.5 + or - 1 km. Egress near 67.6 deg north latitude and 258.4 deg east longitude on the sunlit side yielded a radius of 2439.0 + or - 1 km. The atmospheric measurements showed the electron density to be less than 1000 per cu cm on both sides of the planet. From the latter result one may infer an upper limit to the dayside surface gas density of 1 million molecules per cu cm.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 29; Dec. 197
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  • 66
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    Relation of a contracting earth to the apparent accelerations of the sun and moon (1976)
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    Publication Date: 2011-08-17
    Description: It has been concluded that the theoretical ratio of the apparent secular accelerations of the moon and the sun implied by tidal theory is far higher than the ratio of observed values. This paper shows that the discrepancy can be entirely removed within the range of uncertainty of the various quantities involved if terms making allowance for a secularly decreasing terrestrial moment of inertia are included in the dynamical equations for the apparent secular accelerations. Such a decrease has already been predicted on the basis of the phase-change hypothesis for the nature of earth's core. The development of this hypothesis is reviewed, the modified dynamical equations are derived, and values of tidal couples implied by existing observational data are examined. The numerically determined rate of decrease of earth's moment of inertia is found to be in close agreement with that predicted by the phase-change hypothesis. The results indicate that a diminishing gravitational constant is unlikely, that the moon would have been in close proximity to earth only 1 billion years ago, and that earth's rotation period at that time would have been about 5 hr.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: The Moon; 16; Dec. 197
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  • 67
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    Observational and theoretical temperatures for a total lunar eclipse (1976)
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    Publication Date: 2011-08-17
    Description: Temperature profiles from seven regions of the moon were recorded during a total eclipse using an infrared radiometer and telescope. The eclipse was visible from beginning to end. Target areas chosen range from mare areas to mountainous highlands. Theoretical temperature curves were calculated using a thermophysical model in which the lunar material properties are variable. These curves are compared with the experimental data. A description of the instrumentation, observations, calibration, signal reduction, and the theoretical model is given. The results show excellent agreement between the observational and theoretical temperatures during the eclipse. The apparent differences between the observed and calculated temperatures during pre- and post-eclipse are minimal after directional radiation is taken into account.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: The Moon; 15; June-Jul
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  • 68
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    Floor-fractured lunar craters (1976)
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    Publication Date: 2011-08-17
    Description: Observational data concerning floor-fractured craters on the lunar near and far sides are examined, including the morphologic classification of the craters, their spatial and size distributions, and their floor, peak, and rim elevations relative to the maria. Six morphologic classes and two subclasses are delineated on the basis of fracture pattern, crater floor depth, and floor type. These data are used to reconstruct a history of crater modification which accounts for the large differences in affected crater size and age, the small peak-rim elevation differences, remnant central peaks within mare-flooded craters and ringed plains, ridged and flat-topped rim profiles of heavily modified craters and ringed plains, as well as the absence of positive gravity anomalies in most floor-fractured craters and some large mare-filled craters. The results indicate that: (1) impact craters became centers of intrusions and volcanism generally related to periods of basin inundation by mare basalts; (2) some light-plains units in the highlands may be due to both impact ejecta and extrusions of light-colored lava or ash; (3) floor-fractured craters may have become important volcanic vents that contributed to the inundation of the lunar surface by mare basalts; and (4) the lunar highlands probably did not fully escape the epochs of mare flooding.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: The Moon; 15; June-Jul
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    The chemistry of planetary atmospheres (1976)
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    Publication Date: 2011-08-17
    Description: Present knowledge concerning the chemistry of planetary atmospheres is reviewed along with the theories which attempt to explain observational data. The known gross atmospheric compositions of the terrestrial and giant planets are listed, differences between the atmospheres of earth and Venus are discussed, and the atmospheres of the giant planets are described. The origin and evolution of the atmospheres of earth, Venus, Mars, Jupiter, Saturn, and Uranus are outlined, and chemical processes in the atmospheres are examined, particularly cloud formation. The question of organic synthesis and evolution in the reducing atmospheres of the giant planets is considered. It is noted that laboratory work on the individual chemical processes and reactions involved in the evolution of organic compounds in planetary atmospheres, comets, and interstellar space points to the inevitability of organic-compound synthesis in all these situations and to the pervasiveness of organic chemistry throughout the universe.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Chemical Education; 53; Apr. 197
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    Mars dynamics, atmospheric and surface properties - Determination from Viking tracking data (1976)
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    Publication Date: 2011-08-17
    Description: Approximately three months of radio tracking data from the Viking landers have been analyzed to determine the lander locations, the orientation of the spin axis of Mars, and a first estimate from Viking data of the planet's spin rate. Preliminary results have also been obtained for atmospheric parameters and radii at occultation points and for properties of the surface in the vicinity of lander 1.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Dec. 17
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    Viking magnetic properties investigation - Further results (1976)
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    Publication Date: 2011-08-17
    Description: The amounts of magnetic particles held on the reference test chart and backhoe magnets on lander 2 and lander 1 are comparable, indicating the presence of an estimated 3 to 7 percent by weight of relatively pure, strongly magnetic particles in the soil at the lander 2 sampling site. Preliminary spectrophotometric analysis of the material held on the backhoe magnets on lander 1 indicates that its reflectance characteristics are indistinguishable from material within a sampling trench with which it has been compared. The material on the RTC magnet shows a different spectrum, but it is suspected that the difference is the result of a reflectance contribution from the magnesium metal covering on the magnet. It is argued that the results indicate the presence, now or originally, of magnetite, which may be titaniferous.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Dec. 17
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    Spiral structure as an explanation for the asymmetric brightness of Saturn's A ring (1976)
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    Publication Date: 2011-08-17
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature; 264; Nov. 25
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  • 73
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    Tektites and their origin (1976)
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    Publication Date: 2011-08-17
    Description: Questions concerning the tektite distribution are examined, taking into account the Australasian strewn field, the Ivory Coast strewn field, the Moldavite strewn field, the North American strewn field, the Libyan desert glass, the Aouelloul crater glass, and amerikanites. Attention is given to the shapes of tektites, the internal structure of tektites, the physical properties of tektite glass, the chemical composition of tektites, isotopes, fission tracks, cosmic ray tracks, and arguments in favor and against the terrestrial origin of tektites. It is concluded that tektites cannot be terrestrial in origin. They are probably volcanic ejects, of geologically recent epochs, from one or a number of lunar volcanoes.
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    Viking to Mars - Profile of a space expedition (1976)
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    Publication Date: 2011-08-17
    Description: The Viking spacecraft, operations, and findings are reviewed and numerous pictures are presented in an attempt to capture the atmosphere of the Viking expedition. The details of the two Viking spacecraft, each consisting of an orbiter and lander combination launched a Titan III/Centaur are described and illustrated, along with the Viking ground-data and communications system. The principal conclusions of the Viking mission to date are: detection of nitrogen, argon, krypton, and xenon; determination of isotopic ratios of carbon, nitrogen, oxygen, and argon; uniform diurnal meteorological conditions; determination of major elemental abundances; complex surface chemistry; no ubiquitous organic material; 4 to 7% of the sampled surface material is magnetic; discovery of ancient extensive fluvial activity; north permanent polar cap made of water ice; and significant variations of the atmospheric water vapor, the summer hemisphere being much more humid than the winter hemisphere.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astronautics and Aeronautics; 14; Nov. 197
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    An example of a thermally metamorphosed agglutinate (1976)
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    Publication Date: 2011-08-17
    Description: The nature and properties of lunar agglutinates in relation to the kind of metamorphism described by Albee et al. (1973) are briefly considered. The properties of the agglutinates are compared with those of a lunar metaclastic particle which is believed to be the product of the extreme thermal metamorphism of an agglutinate. The results of electronprobe microanalyses of selected agglutinitic glasses are presented in a table. Attention is also given to the bulk chemical composition of some noritic metaclastic rocks and several highland rock types.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics; 11; Sept. 30
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    Unlimbering Viking's scoop (1976)
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    Publication Date: 2011-08-17
    Description: A number of difficulties which were encountered in deploying the Viking 1 lander's surface-sampler arm are discussed. When the surface sampler jammed during its initial operation, the problem was studied with the aid of tests on a full-scale lander mock-up. It was found that the difficulty was caused by a boom latch pin which had failed to fall clear. The surface-sampler arm could subsequently be freed by modifying the original command sequence. Another difficulty could be overcome by a similar approach.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: IEEE Spectrum; 13; Oct. 197
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  • 77
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    A radar study of the backup Martian landing sites (1976)
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    Publication Date: 2011-08-17
    Description: The Goldstone radar system at DSS 14 was used to probe the Martian surface at 8495 MHz in a narrow strip between -6 deg and -2 deg latitude. The Viking C landing sites lie in this strip, and their altitudes, rms surface slope, and reflectivity are presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: The Deep Space Network; p 49-52
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    A geological basis for the exploration of the planets: Introduction (1976)
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    Publication Date: 2011-08-17
    Description: The geological aspects of solar-system exploration were considered by first showing how geologic data are related to space science in general, and, second, by discussing the approach used in planetary geology. The origin, evolution, and distribution of matter condensed in the form of planets, satellites, comets, and asteroids were studied. Terrestrial planets, comets, and asteroids, and the solid satellites of the outer planets are discussed. Jupiter and Saturn, in particular, have satellites of prime importance. Geophysics, geochemistry, geodesy, cartography, and other disciplines concerned with the solid planets were all included.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: A Geol. Basis for the Exploration of the Planets; p 1-12
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    Viking magnetic properties investigation - Preliminary results (1976)
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    Publication Date: 2011-08-16
    Description: Three permanent-magnet arrays are aboard the Viking lander. By sol 35, one array, fixed on a photometric reference test chart on top of the lander, has clearly attracted magnetic particles from airborne dust; two other magnet arrays, one strong and one weak, incorporated in the backhoe of the surface sampler, have both extracted considerable magnetic mineral from the surface as a result of nine insertions associated with sample acquisition. The loose Martian surface material around the landing site is judged to contain 3 to 7 per cent highly magnetic mineral which, pending spectrophotometric study, is thought to be mainly magnetite.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Oct. 1
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    Search for the Viking 2 landing site (1976)
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    Publication Date: 2011-08-16
    Description: The search for the landing site of Viking 2 is reviewed, emphasizing the characteristics of the various candidate sites and reasons for rejecting unsuitable sites. It is shown that the B3 site in Utopia Planitia was selected because the B latitude band (40 to 50 deg N) was of the highest scientific interest, the site appeared to be smoothed by uniform mantling, and the additional data analysis and acquisition required to land at any other site could have resulted in a landing delay and significant additional operational complexity. It is tentatively concluded that the Viking 2 lander rests in a deflation hollow.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Oct. 1
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    K/S two-point-boundary-value problems (1976)
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    Publication Date: 2011-08-17
    Description: A method for developing the missing general K/S (Kustaanheimo/Stiefel) boundary conditions is presented, with use of the formalism of optimal control theory. As an illustrative example, the method is applied to the K/S Lambert problem to derive the missing terminal condition. The necessary equations are developed for a solution to this problem with the generalized eccentric anomaly, E, as the independent variable. This formulation, requiring the solution of only one nonlinear, well-behaved equation in one unknown, E, results in considerable simplification of the problem.
    Keywords: ASTRONOMY
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    Mapping of lunar surface from side-looking orbital radar images (1976)
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    Publication Date: 2011-08-17
    Description: Side-looking spacecraft radar imagery has thus far been produced only from an orbit around the moon. This was a part of the Apollo Lunar Sounder Experiment (ALSE) of the Apollo 17 mission in December 1972. This paper reports results of a radargrammetric evaluation of overlapping Apollo 17 synthetic-aperture radar images (wavelength 2 m). The potential to map from single images and to reconstruct three-dimensional stereoscopic models is studied. The relative height accuracy achieved is about + or - 100 m and is thus competitive with that obtained with the vidicon camera presently used for planetary exploration.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: The Moon; 15; June-Jul
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    Trajectories and orbits from the NASA-NMSU meteor observatory. I (1976)
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    Publication Date: 2011-08-17
    Description: Reduced trajectory data and orbital elements are reported for 20 double-station meteors photographed at the NASA-NMSU meteor observatory during the winter of 1974/75. The objects photographed include 10 sporadic meteors and 10 members of the Geminid shower. The data for the sporadic meteors indicate that their magnitudes range from 0 to -4, all have eccentricities greater than 0.4, all but three are in direct orbits, and one is probably a member of the Coma Berenicid shower. The elements for the Geminids are obtained using times of appearance chosen by adopting 34.6 km/s as the heliocentric velocity of the shower. The results are compared with previous orbital determinations, and it is concluded that there is no evidence for significant evolution of the Geminid-stream orbit over a period of several decades.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 81; Nov. 197
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  • 84
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    Martian north pole summer temperatures - Dirty water ice (1976)
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    Publication Date: 2011-08-17
    Description: Broadband thermal and reflectance observations of the Martian north polar region in late summer yield temperatures for the residual polar cap near 205 K with albedos near 43 percent. The residual cap and several outlying smaller deposits are water ice with included dirt; there is no evidence for any permanent carbon dioxide polar cap.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Dec. 17
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    The Viking seismic experiment (1976)
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    Publication Date: 2011-08-17
    Description: A three-axis short-period seismometer is now operating on Mars in the Utopia Planitia region. The noise background correlates well with wind gusts. Although no quakes have been detected in the first 60 days of observation, it is premature to draw any conclusions about the seismicity of Mars. The instrument is expected to return data for at least 2 years.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 194; Dec. 17
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    Discovering Jupiter. I (1976)
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    Publication Date: 2011-08-17
    Description: The current state of knowledge regarding the planet Jupiter is examined, taking into account data obtained with the aid of the spacecraft Pioneer 11. A description is given of Jupiter's weather. The Pioneer 11 pictures show that the planet's banded cloud structure breaks down above 50 deg latitude, and turns into relatively small, mostly circular cloud features in the polar regions. Attention is given to Jupiter's heat balance, aspects of internal heat flow, questions of atmospheric circulation, the turbulence in Jupiter's atmosphere, the effects of coriolis forces, Jupiter's upper atmosphere, the Great Red Spot, and the Jovian magnetosphere and radiation belts.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Spaceflight; 18; Dec. 197
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    Emission nebulae in the Magellanic Clouds. I - The H II regions (1976)
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    Publication Date: 2011-08-17
    Description: A review of optical and radio studies of the H II regions in the Magellanic Clouds is presented. Recent studies are emphasized, particularly optical studies of the kinematics, spectra, and chemical composition. The implications of the studies for the understanding of the evolution of stars and galaxies in general, and the Magellanic Clouds in particular, are noted. Suggestions for future work are also given.
    Keywords: ASTRONOMY
    Type: Earth and Extraterrestrial Sciences; 2; June 197
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    Minor planets and related objects. XXI - Photometry of eight asteroids (1976)
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    Publication Date: 2011-08-17
    Description: Light curves, UBV colors, rotational periods, phase coefficients, and absolute magnitudes are presented. The asteroids studied are (1) Ceres, (4) Vesta, (16) Psyche, (78) Diana, (281) Lucretia, (451) Patientia, (1212) Francette, and (1362) Griqua. The rotation axis of Lucretia is nearly perpendicular to the plane of the ecliptic. Ceres appears to be nearly spherical with an absolute magnitude of B(1,0)=4.42, which is 0.3 mag fainter than previously reported. The determination of the absolute magnitude for an asteroid depends on its aspect, and for each opposition there is, therefore, a different absolute magnitude.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 81; Sept
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    NASA's 91-cm. airborne telescope (1976)
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    Publication Date: 2011-08-17
    Description: The Gerard P. Kuiper Airborne Observatory (KAO), commissioned in May 1975, is the result of the multi-year NASA program of infrared observations from high-flying aircraft. The KAO is a highly modified Lockheed C-141 jet transport, equipped with a 91-cm bent-Cassegrain telescope, as an international facility for research in infrared astronomy. To minimize the effects of aircraft vibration, the telescope is mounted on four pneumatic shock absorbers, and the entire assembly is balanced on the side of a spherical compressed-air bearing, containing a 0.018 mm-thick air film under a pressure of 19 atmospheres. The use of the KAO is not limited to infrared research, its total observable wavelength band extending from the near UV (3000 A) to the millimeter region. Design and technical characteristics of the telescope are discussed, including the image stabilization and target acquisition systems, as well as observational results obtained during the first year of the KAO operation.
    Keywords: ASTRONOMY
    Type: Sky and Telescope; 52; Nov. 197
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    Stratigraphy and structural geology (1976)
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    Publication Date: 2011-08-17
    Description: The immediate goal of stratigraphy and structural geology is to reduce the enormous complexity of a planetary surface to comprehensible proportions by dividing the near-surface rocks into units and mapping their distribution and attitude.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: A Geol. Basis for the Exploration of the Planets; p 13-32
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    Geophysics (1976)
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    Publication Date: 2011-08-17
    Description: Four areas of investigation, each dealing with the measurement of a particular geophysical property, are discussed. These properties are the gravity field, seismicity, magnetism, and heat flow. All are strongly affected by conditions, past or present, in the planetary interior; their measurement is the primary source of information about planetary interiors.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: A Geol. Basis for the Exploration of the Planets; p 63-74
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    Geodesy and cartography (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Geodesy and cartography provide the geometric framework on which most investigations of planets are ultimately based. Specifically, the products of these disciplines provide information on the following: (1) the dimensions of the planet, (2) a mathematical figure of reference for the planet, (3) the orientation of the body in the celestial coordinate system, (4) the rotational constants, (5) a defined system of coordinates, (6) the location of surface points in the defined coordinate system, (7) the gravity potential expressed in spherical harmonics, (8) topographic and thematic maps, and (9) surface albedo in various wavelengths. The relevance of geodesy and cartography to planetology is discussed, and the requirements of data acquisition and mission design are considered.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA Ames Res. Center A Geol. Basis for the Exploration of the Planets; p 75-84
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    Geochemistry (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The most effective strategy for the geochemical study of a planet is to proceed systematically with the mineralogical and chemical characterization of its materials in accordance with geologically determined priorities. It is insufficient merely to analyze chemically the surface rocks. To appreciate the meaning of a chemical analysis, some assessment must be made of the geologic history of the sample - what its source and mode of origin are and what processes have operated upon the sample to cause chemical fractionation. Determination of mineralogy, texture, lithology, and other properties of the rock that might be relevant to origin is, therefore, necessary.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA Ames Res. Center A Geol. Basis for the Exploration of the Planets; p 33-62
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    Photometry of Venus from Mariner 10 (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Photometry of the upper atmosphere of Venus from Mariner 10 on February 5, 1974 is discussed with respect to in-flight verification of camera linearity, shading, and absolute photometric calibration. Among photometric results are the following: (1) temporal brightness variations were observed in the UV greater than 10% over a few hours due to the rapid rotation of the upper atmosphere, (2) the observed terminator was 4 degrees past the geometric terminator due to detached haze layers at altitudes around 85 km, (3) there were no indications of cloud top elevation variations greater than a few hunderd meters, and (4) in the UV, the bright and dark regions both had low albedos in all scales, showing that the UV absorber is not confined just to dark markings.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of the Atmospheric Sciences; 33; Sept
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  • 95
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    Jupiter at five microns (1976)
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    Publication Date: 2011-08-16
    Description: The paper summarizes the information obtained in recent maps of Jupiter at 5 microns, a frequency at which the gases in Jupiter have a relatively low opacity. It is highly possible that 5-micron hot spots are breaks in the cloud deck permitting observation of the hot lower layers of the atmosphere. Many 5-micron sources coincide with blue visual features, but the details of the correspondence need further investigation. Large-scale changes in the appearance of the planet occur at 5 microns on time scales of months; these changes are sufficiently dramatic to produce detectable variations in the whole-disk flux from the planet. Their correspondence to large-scale changes in visual features is not yet determined.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 96
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    Calculation of the twilight visibility function of near-sun objects (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The visibility function, defined here as the magnitude difference between the excess brightness of a given object and that of the background sky, of near-sun objects during twilight is obtained from a general calculation which considers the twilight sky background, atmospheric extinction, and night glow. Visibility curves are computed for a number of cases in which observations have been recorded, particularly that of comet Kohoutek. For this object, the computed visibility maxima agree well in time with the reported times of observation.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society of Canada; vol. 70
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    Bow shock and magnetosheath waves at Mercury (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Mariner 10 measurements at the Mercury bow shock provide examples where the magnetic field is approximately parallel or perpendicular to the bow shock normal. Upstream of a broad irregular parallel shock, left-hand circularly polarized waves are observed which cut off very sharply at about 4 Hz. Upstream of a perpendicular shock, righ-hand circularly polarized waves are observed which persist up to the Nyquist frequency of 12 Hz. Determination of the wave propagation vector as a function of frequency helps to identify conclusively the waves as whistler mode waves propagating from the shock. The magnetosheath downstream of the parallel shock is disturbed more than that downstream of the perpendicular shock, particularly below 1 Hz. In the latter case, regular left-hand-polarized waves observed slightly above the proton gyrofrequency are identified as ion cyclotron waves with wavelengths of about 300 km which have been Doppler shifted up to their observed frequency.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 81; Aug. 1
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  • 98
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    Mars - Wind friction speeds for particle movement (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Wind friction threshold speeds for particle movement were determined in a low pressure boundary layer wind tunnel at an atmospheric pressure of 5.3 mb. The results imply that for comparable pressures on Mars, the minimum wind friction threshold speed is about 2.5 m/sec, which would require free-stream winds of 50 to 135 m/sec, depending on the character of the surface and the atmospheric conditions. The corresponding wind speeds at the height of the Viking lander meteorology instrument would be about a factor of two less than the free-stream wind speed. The particle size most easily moved by winds on Mars is about 160 microns; particles both larger and smaller than this (at least down to about 5 microns) require stronger winds to initiate movement.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters; 3; Aug. 197
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  • 99
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    The first Viking mission to Mars (1976)
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    Publication Date: 2011-08-16
    Description: The paper outlines the major goals and present achievements of the Viking 1 mission to Mars. The construction and instrumentation of the orbiter and lander are described. The criteria used to select the optimum landing site are discussed together with orbit adjustments and the landing process. Special attention is given to constraints on surface coverage and observation conditions.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 193; Aug. 27
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    Emissivities and detectability of the pure rotational transitions of molecular hydrogen (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The emissivities of the infrared rotational transitions of H2 are calculated for temperatures from 10 K to 6000 K. The calculations are made for several ratios, R, of Para (J=0) to Ortho (J=1)H2. The possibility of detecting these transitions in interstellar molecular clouds is discussed.
    Keywords: ASTRONOMY
    Type: Contrib. of the Observatory of N. Mex. State Univ., Vol. 1, No. 4; p 123-133
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