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  • Inorganic Chemistry  (7,653)
  • LUNAR AND PLANETARY EXPLORATION  (3,679)
  • ASTROPHYSICS  (2,155)
  • Ertrag
  • 1975-1979  (9,613)
  • 1930-1934  (3,902)
Collection
Keywords
Publisher
Years
Year
  • 1
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    Ertrag und Zuckergehalt der Zuckerrübe in Beziehung zu den grundlegenden Klimafaktoren (1979)
    In:  Rost. Výr. 25 (4):385-397
    Details
    Publication Date: 1979
    Description: Berechnung des hydrotherm. Koeffizienten, Einfluss der Temperatur und der Niederschläge auf Ertrag und Zuckergehalt durch Korrelationsmethode, Einteilung in Zeitabschnitte, Bezeichnung kritischer Phasen anhand 21jähriger Auswertung für eine bestimmte Region KATASTER-BESCHREIBUNG: Einfluß auf die Bildung der Rübenmasse durch hohe Temperaturen während der letzten Februar Dekade und im März sowie überdurchnittlich warme 2. Hälfte des Dezember und die 1. Hälfe des Januars, Niederschlagshöhe ist in den Monaten Mai, Ende August und Anfang September entscheidend KATASTER-DETAIL:
    Keywords: Tschechien ; 1956-77 ; Zuckerrüben ; Ertrag ; Korrelationsmethode ; Niederschlag ; Temperatur ; Hackfrüchte
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  • 2
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    Getreide-Erntebeginn und Frühsommertemperaturen im schweizerischen Mittelland seit dem 17. Jhd. (1979)
    In:  Geographica Helvetica; Nr. 1; p.23-35.
    Details
    Publication Date: 1979
    Description: Angaben über Zehntsteigeungsdaten und Aufzeichnungen über Erntebeginn werden genutzt, um Temperaturdaten des Frühsommers (Mai-Juli) zu generieren KATASTER-BESCHREIBUNG: Die Reife der Ernte ist abängig von der Mai/Juni-Temperatur KATASTER-DETAIL: Delta T (Mai, Juni) -, dann Getreideerntebeginn - (später)
    Keywords: Schweizerisches Mittelland ; 1611-1825, 1876-1950 ; Ertrag ; Getreide ; Temperatur
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  • 3
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    Beziehung zwischen dem Bodenfeuchtegehalt und den Erträgen wichtiger landwirtschaftlicher Fruchtarten auf zwei unterschiedlichen Schwarzerdestandorten (1979)
    In:  Arch. Acker- und Pflanzenbau und Bodenkunde 23 (7):429-439
    Details
    Publication Date: 1979
    Description: Versuche mit Kartoffeln, Weidelgras, Zuckerrüben und Winterweizen zur Bodenfeuchtestaffelung sowie Ableitung von günstigen Bodenfeuchtespannen aus den Ergebnissen; Auswertung von Versuchen mit Kartoffeln, Weidelgras, Zuckerrüben und Winterweizen zeigen Zusammenhang zwischen Bodenfeuchte und Ertragsrückgang KATASTER-BESCHREIBUNG: Einfluss der Bodenfeuchte auf den Ertrag KATASTER-DETAIL: Delta Bodenfeuchte (Löß-Braunschwarzerde 0-50 cm) = 50 - 70 % nFÄ, dann Ertrag (Zuckerrüben zur Fütterung) +; Delta Bodenfeuchte (Löß-Braunschwarzerde 0-50 cm) = 50 - 60/65 % nFÄ, dann Ertrag (Zuckerrüben zur zuckergewinnung) +; Delta Bodenfeuchte (Löß-Braunschwarzerde 0-50 cm) = 40 - 55/60 % nFÄ, dann Ertrag (Kartoffeln - einschl. Stärke) +; Delta Bodenfeuchte (Löß-Braunschwarzerde 0-50 cm) = 55/60 - 75/80 % nFÄ, dann Ertrag (Welsches Weidelgras bis Mitte August) +; Delta Bodenfeuchte (Löß-Braunschwarzerde 0-50 cm) = 50 - 70 % nFÄ, dann Ertrag (Welsches Weidelgras nach Mitte August) +; Delta Bodenfeuchte (Löß-Braunschwarzerde 0-50 cm) = 50 - 65/70 % nFÄ, dann Ertrag (Winterweizen) +; Delta Bodenfeuchte (Ton-Schwarzerde 0-40 cm) = 45/50 - 60/65 % nFÄ, dann Ertrag (Zuckerrüben) +; Delta Bodenfeuchte (Ton-Schwarzerde 0-40 cm) = 50 - 70 % nFÄ, dann Ertrag (Welsches Weidelgras) +; Delta Bodenfeuchte (Ton-Schwarzerde 0-40 cm) = 50 - 70/75 % nFÄ, dann Ertrag (Kartoffeln - einschl. Stärke) +;
    Keywords: Thüringen ; 1968-1972 ; Kartoffeln ; Ertrag ; Niederschlag ; Trockenheit ; Verdunstung ; Wassermangel ; Weizen ; Hackfrüchte
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  • 4
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    Some unique meteorites found in Antarctica and their relation to asteroids (1979)
    In:  Other Sources
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    Publication Date: 2011-08-24
    Description: Two unique meteorites were identified by means of a mineralogical examination of the smaller-sized Yamato achondrites. Yamato-74130 is the most iron-rich ureilite with Na, Cr-rich augite instead of pigeonite. Yamato-74160 was extensively recrystallized, but the composition and proportion of olivine, orthopyroxene, augite, and plagioclase is consistent with LL7 chondrites. ALHA77005 is a unique achondrite with olivine, possibly three pyroxene assemblages, and maskelynite. These meteorites provide evidence that there may be other 'thermalized' asteroids than the howardite parent body. Detailed petrologic descriptions of the unique achondrites, recrystallized diogenite Yamato-74013, and the rapidly cooled eucrite Yamato-74450 with pyroxene phenocrysts are given. It is inferred from the bulk chemistry and the mineralogical reexamination of Yamato-75028 that it is composed of the H5-type clasts and chondrule-rich H(L)3-like matrix with the H5 fragments. A close relationship in the collisional evolution of some asteroids with these materials is inferred.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: National Institute of Polar Research, Memoirs (ISSN 0386-0744); 15, 1; 54-76
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  • 5
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    Meteoroid protection for the Comet Halley probe (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-26
    Description: The high closing speed of 57km/s between the spacecraft and Halley poses special problems in the design of the required meteoroid protection. A double wall structure with a total thickness equal to 0.1 to 1 times the diameter of the largest meteoroid encountered is sufficient to stop that meteoroid. However, the unusually high number of meteoroid impacts on the Halley probe will cause significant erosion of the outer wall so that failure of the second wall is more likely to occur from a small meteoroid passing through a previously created hole in the outer wall and then penetrating the second wall. Calculations of the shielding required based on this failure mode, show that a double wall structure must actually have a total thickness 1.2 to 7.3 times the diameter of the largest meteoroid encountered, depending on the size distribution of the meteoroids.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: ESA Comet Halley Micrometeoroid Hazard Workshop; p 73-76
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  • 6
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    Precise determination of the distances of galaxies (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The use of the Space Telescope in the determination of the distances of galaxies is examined. The Space Telescope can check the local extragalactic distance scale to within 10-15 percent. The determination of relative distances of cosmic standard candles, viz. brightest M-supergiants and SNe I in E galaxies, is discussed. The M-supergiants map the velocity field out to v sub o approx. 3000 km s(-1) thus providing a firm basis for the determination of H sub o (global) from local distances, and the possibility to derive precise distances of all nearby field galaxies from their recession velocities. Photometry of the SNe I out to z = 0.5 leads to a direct determination of q sub o via the Hubble diagram, and the form of their light curves offers a fundamental test on the nature of redshifts. Other calculations are discussed.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 263-293
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  • 7
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    Requirements for predictions and real-time monitoring for the study of travelling interplanetary phenomena (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Physical processes within quiescent as well as disturbed flows of solar wind plasma, energetic particles, and magnetic and electric fields from the Sun are considered. Specifically, travelling interplanetary phenomena to be studied during the years of the solar maximum of solar cycle 21 are covered. It is noted that predictions, while needed for long range, logistical planning, is secondary to the requirements of synoptic real time monitoring over a wide range of particle energies and spectral bandwidths.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 340-345
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  • 8
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    Space vehicle meteoroid shielding design (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Design principles of spaced, multiwall meteoroid protection are investigated in the light of experimental data generated during the Apollo Program. The outer wall or shield is shown to be the most important element in the meteoroid-spacecraft interaction. The condition of the debris is primarily a function of the shock pressure, the melting points of the meteoroid and the shield, and the length of the meteoroid and thickness of the shield. Spacing between the walls is effective up to approximately 100 times the length of the meteoroid. The required thickness of the second wall is shown to be proportional to the meteoroid mass, velocity, and density, and to the spacing between the walls, taken with exponents dependent upon the condition of the debris. The effects of placing additional elements (insulation or honeycomb cells) between the two walls are discussed, and the efficiency of various protective configurations is presented. An analysis of the meteoroid protection proposed for the Comet Halley probe is included as an appendix.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: ESA Comet Halley Micrometeoroid Hazard Workshop; p 85-92
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  • 9
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    The problems of cosmology (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Three examples that illustrate the expected role of the Space Telescope in cosmological investigations are described addressing the distribution of globular star clusters, universe expansion, and other classical cosmological problems.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 295-312
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  • 10
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    The central regions of active galaxies and quasars (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Theories describing the central regions of nonthermal extragalactic sources (radio galaxies, Seyfert nuclei, quasars, etc.) are examined in the light of the experimental possibilities afforded by the Space Telescope. In particular, the theory which proposes the accretion of stars or gas onto a black hole as the explanation of the central engine is discussed. Planned observations directed towards the problem of the mass, size, and structure of the central engine, and the phenomenological questions regarding the general environment of the central engine are outlined.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 197-214
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  • 11
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    Luminosity functions and evolution of globular clusters (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The stellar dynamics of globular clusters are addressed in terms of luminosity functions, chemical topics, and dynamical topics
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 139-150
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  • 12
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    Mining and beneficiation of lunar ores (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The beneficiation of lunar plagioclase and ilmenite ores to feedstock grade permits a rapid growth of the space manufacturing economy by maximizing the production rate of metals and oxygen. A beneficiation scheme based on electrostatic and magnetic separation is preferred over conventional schemes, but such a scheme cannot be completely modeled because beneficiation processes are empirical and because some properties of lunar minerals have not been measured. To meet anticipated shipping and processing needs, the peak lunar mining rate will exceed 1000 tons/hr by the fifth year of operation. Such capabilities will be best obtained by automated mining vehicles and conveyor systems rather than trucks. It may be possible to extract about 40 kg of volatiles (60 percent H2O) by thermally processing the less than 20 micron ilmenite concentrate extracted from 130 tons of ilmenite ore. A thermodynamic analysis of an extraction process is presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Resources and Space Settlements; p 275-288
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  • 13
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    A geologic assessment of potential lunar ores (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: Although bulk lunar soil is not a suitable feedstock for extracting metals, certain minerals such as anorthite and ilmenite can be separated and concentrated. These minerals can be considered as potential ores of aluminum, silicon, titanium, andiron. A separation and metal extraction plant could also extract large amounts of oxygen and perhaps hydrogen from these minerals. Anorthie containing 19 percent aluminum and 20 percent silicon can be concentrated from some highland soils where it is present in amounts up to 60 percent. Ilmenite containing 32 percent titanium and 37 percent iron can be concentrated from some mare soils where it is present in amounts up to 10 percent. The ideal mining site would be located at the boundary between a high-titanium mare and a high-aluminum highlands. Such area may exist around the rims of some eastern maria, particularly Tranquilitatis. A location on Earth with raw materials as described above would be considered an economically valuable ore deposit if conventional terrestrial resources were not available.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA. Ames Res. Center Space Resources and Space Settlements; p 243-255
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  • 14
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    Sample fields of the Viking landers, physical properties, and aeolian processes (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Surface sampler activities on Mars during the Viking extended mission are considered, including excavation of deep trenches, construction of conical piles of materials, backhoe touchdown experiments, and acquisition of contiguous pictures of the surface beneath number 2 terminal descent engines using mirrors. Results of the Physical Properties Investigation that are relevant to aeolian processes are also discussed. Both pictures and surface sampler data indicate that the surface materials in the sample fields of the Viking landers may be grouped, in order of increasing strength, into drift material, crusty to cloddy material, blocky material and rocks.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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  • 15
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    Pitted and fluted rocks in the Western Desert of Egypt - Viking comparisons (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Western Desert of Egypt is one of the most arid regions on earth and is probably the closest terrestrial analog to the surface of Mars. An expedition to the area in 1978 revealed an abundance of quartzite and basalt rocks that have been pitted and fluted by wind erosion and deflation of the desert surface. These pitted rocks are internally homogeneous, show no internal holes or vesicles, and are considered an important but neglected type of ventifact. They bear a striking resemblance to the pitted and fluted rocks seen by the Viking Landers, rocks that have generally been interpreted as vesicular basalts only slightly modified by wind erosion. Wind tunnel studies of the air flow over and around nonstreamlined hand specimens from the Western Desert show that windward abrasion coupled with negative flow, secondary flow, and vorticity in a unidirectional wind can explain the complex arrays of pits and flutes. These field and laboratory observations suggest that the pitted rocks at the Viking Lander sites are also ventifacts, and thus the Martian surface may be far more wind eroded than previously thought.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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  • 16
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    Morphology and distribution of common 'sand' dunes on Mars - Comparison with the earth (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A comparative study of Martian and terrestrial dunes was made based on Viking Orbiter pictures and aerial pictures of terrestrial deserts. The morphological similarity between the Martian dunes and terrestrial crescentic dunes implies that the dynamics of dune formation are similar on the two planets, despite Martian constraints on dune formation that include much higher velocity winds required to move 'sand' in saltation, the possible inhibition of sand movement by absorbed water vapor, the seasonal 'snow' cover in the north circumpolar erg, and a probably sparse sand supply. The absence of longitudinal dunes and the restriction of massive crescentic dunes to a few sites on Mars suggests that Mars may have a long eolian history in which much of the sand suitable for saltation has already been transported to the north polar erg and crater floor fields.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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  • 17
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    The X-ray spectrum of 3C 273 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 232
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  • 18
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    Viking magnetic properties experiment - Extended mission results (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The backhoe magnets on Viking Lander (VL) 2 were successfully cleaned, followed by a test involving successive insertions of the cleaned backhoe into the surface. Rapid saturation of the magnets confirmed evidence from primary mission results that the magnetic mineral in the Martian surface is widely distributed, most probably in the form of composite particles of magnetic and nonmagnetic minerals. An image of the VL 2 backhoe taken via the X4 magnifying mirror demonstrates the fine-grained nature of the attracted magnetic material. The presence of maghemite and its occurrence as a pigment in, or a thin coating on, all mineral particles or as discrete, finely divided and widely distributed crystallites, are consistent with data from the inorganic analysis experiments and with laboratory simulations of results of the biology experiments on Mars.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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  • 19
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    Primordial heating of asteroidal parent bodies (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Most meteorites show evidence of thermal processing either because of metamorphic changes or as a result of melting and differentiation. Proposed mechanisms for supplying this energy generally rely upon short-lived radioisotopes or electrical induction, though accretion is sometimes mentioned, and more exotic models have been discussed. Interest in isotopic heating has been heightened by the discovery of Al-26 in Allende inclusions and also by the proposal that a lunar core and dynamo resulted from the radioactive decay of superheavy elements during the early solar system. Electrical induction as a heat source can be scaled to a broad range of solar system conditions, but corroborative evidence for these conditions is inconclusive. The accretion mechanism is probably not viable for the asteroidal and meteorite parent bodies, because the high kinetic energy requirement is inconsistent with the formation of the objects and their regoliths in the presence of a weak gravitational field.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 20
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    Aqueous activity on asteroids - Evidence from carbonaceous meteorites (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Carbonaceous chondrites of groups CI and CM were formed by impact brecciation and aqueous alteration of earlier generations of mineral phases within the surface regions of two or more parent bodies. Those parent bodies were probably asteroids, rather than comets, although a problem still exists in delivering such material safely to earth. Aqueous activity may have been widespread on asteroids.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 21
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    Diverse puzzling asteroids and a possible unified explanation (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Recent observations have led to unconventional models of certain asteroids, suggesting previously unsuspected forms. Some of these include binary asteroids (e.g., 532 Herculina, 18 Melpomene), very irregular asteroids (e.g., the Mars-crossing 1580 Betulia), and very elongated asteroids, unlikely to be collisional fragments (e.g., 624 Hector). A connection is suggested between this observational work and ongoing theoretical work concerning collisions of large comparable-sized asteroids. Such collisions have different consequences from the collisions usually considered. The new work suggests possible sources of elongated and binary asteroids.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 22
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    Radio observations of asteroids - Results and prospects (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Radio observations of the asteroids can provide information on the thermal and dielectric properties of the surface materials and, because the radio emission arises somewhat below the surface, the data give some indication of layering. Observational difficulty has limited the investigations to only 6 asteroids. 1 Ceres and 324 Bamberga appear to have a layer of dust covering a more compacted material; the data on 4 Vesta cannot be matched by any current models for the surface; and the results for 18 Melpomene, 31 Euphrosyne and 433 Eros are too incomplete for firm conclusions. Future possibilities include more accurate radiometry of a few selected asteroids of different taxonomic classes and actual resolution of some of the larger objects by aperture synthesis techniques.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 23
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    Optical polarimetry of asteroids and laboratory samples (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Interpretations of astronomical polarization data for more than 100 minor planets are summarized with reference to laboratory data for lunar, meteoritic, and terrestrial samples. All observed asteroids, including objects only a few kilometers in diameter, have microscopically intricate surfaces. Detailed comparisons between laboratory measurements of basaltic achondrites and telescopic results for Vesta show that its surface is particulate with a broad range of particle sizes, including a component of fine (1-5 micron) dust. The surface soils have not, however, undergone marked optical alterations as is the case for the lunar fines. For albedos greater than about 0.06, the albedo and hence the diameter can be determined with some reliability from the slope of the ascending branch of the polarization-phase curve. Many minor planets have surfaces that are remarkably uniform in albedo and texture on a hemispheric scale. A notable exception is 4 Vesta, which shows about ten percent albedo variegation between hemispheres.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 24
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    The asteroids - Nature, interrelations, origin, and evolution (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper deals with the physical and chemical nature of the asteroids and with their physical and orbital distributions and interrelationships. Existing hypotheses about the formation and evolution of asteroids are examined. A thematic synopsis of these topics is presented, and accepted interpretations are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 25
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    Review of the metallographic cooling rates of meteorites and a new model for the planetesimals in which they formed (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The cooling rates of meteorites through approximately 900 -650 K, as read from their metal alloy compositions, are reviewed. Metallographic cooling rates are compared with the cooling rates that appear to be required by the K/Ar and Ar-40/Ar-39 ages of five meteorite classes, and discrepancies are found in all cases. Either (1) the metallographic cooling rates (and also Pu-244 fission cooling rates) are systematically in error, being too slow by a factor of approximately 6; or (2) the traditional thermal model for parent meteorite planets (having constant dimension and uniform physical properties) is oversimplified and the Ar closure temperatures for chondrites derived by Turner et al. (1978) are too low. An alternative parent planet model is proposed and numerically modeled, in which accretion of thermally insulating particulate matter, heat generation by Al-26 decay, melting or sintering of the particulate matter into conductive rock, and establishment of the properties of the meteorites occurred concurrently. Meteorite chronologies are somewhat easier to understand in this context, since the initially small, hot (thus sintered and conductive) bodies would have cooled rapidly to isotopic closure, but later cooling might have been much slower as a result of the continued accretion of insulating particulate matter.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 26
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    Asteroid taxonomy and the distribution of the compositional types (1979)
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    Publication Date: 2011-08-17
    Description: Physical observations of minor planets documented in the TRIAD computer file are used to classify 752 objects into the broad compositional types C, S, M, E, R, and U (unclassifiable) according to the prescriptions adopted by Bowell et al. (1978). Diameters are computed from the photometric magnitude using radiometric and/or polarimetric data where available, or else from albedos characteristic of the indicated type. An analysis of the observational selection effects leads to tabulation of the actual number of asteroids, as a function of type and diameter, in each of 15 orbital element zones. For the whole main belt the population is 75% of type C, 15% of type S, and 10% of other types, with no belt-wide dependence of the mixing ratios on diameter. In some zones the logarithmic diameter-frequency relations are decidedly nonlinear. The relative frequency of S-type objects decreases smoothly outward through the main belt, with exponential scale length 0.5 AU. The rarer types show a more chaotic, but generally flatter, distribution over distance. Characteristic type distributions, contrasting with the background population, are found for the Eos, Koronis, Nysa and Themis families.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 27
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    Phobos and Deimos - A preview of what asteroids are like (1979)
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    Publication Date: 2011-08-17
    Description: The surfaces of Phobos and Deimos are discussed, as the best available examples of what asteroid surfaces may be like. Attention is given to shape, regolith properties, crater densities, albedo markings and surface gravities. It is found that although the surfaces of these two similarly-sized asteroid-like bodies are nearly identical in terms of many disk-integrated properties, they are strikingly different in surface morphology.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Radar observations of asteroids (1979)
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    Publication Date: 2011-08-17
    Description: Radar observations of asteroids use simple CW waveforms, the transmissions lasting for the duration of the round-trip delay. The echo is received, spectrum-analyzed, and integrated for a similar period. Since radar coherently illuminates the target, the surface scattering properties at radio wavelengths are directly determined as a function of angle and polarization. The distance and radial velocity obtained with radar complement the angular position of the object as determined from telescope measurements. Radar cross sections, scattering law, and radius are given for radar-observed asteroids.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Masses and densities of asteroids (1979)
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    Publication Date: 2011-08-17
    Description: Ceres, Pallas, and Vesta allow a determination of mass from gravitational effects in the motion of another asteroid. An extended and partly corrected set of observations of 197 Arete leads to an increase of 15% in the resulting mass of Vesta that was first determined by Hertz. Other possibilities of mass determination and estimates of the total mass of asteroids are mentioned. The available diameter determinations and adopt preferred values are reviewed. The densities for Ceres, Pallas, and Vesta are respectively 2.3 plus or minus 1.1 g/cu cm, 2.6 plus or minus 0.9 g/cu cm and 3.3 plus or minus 1.5 g/cu cm.
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    Interstellar C2 molecules toward Zeta Persei (1979)
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    Publication Date: 2011-08-17
    Description: A search for absorption by interstellar C2 molecules, conducted at the (2-0) Phillips band near 8760 A, is reported for three stars. No interstellar absorption is seen in the spectra of 20 Tau and Epsilon Aur, at upper limits of approximately 5 mA and 1 mA, respectively. Toward Zeta Per, however, the R(0), Q(2), and Q(4) lines are detected, and a useful upper limit on the Q(6) line is obtained. The resulting column density, 1.4 x 10 to the 13th to 2.0 x 10 to the 13th per sq cm, and the excitation temperature, T = (78 plus or minus 25) K, show acceptable agreement with an existing theoretical model of the absorbing cloud.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 232
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    Galaxies and gamma-ray astronomy (1979)
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    Publication Date: 2011-08-17
    Description: The nature of the high-energy spectra of several types of active galaxies and their contribution to the measured diffuse gamma-ray emission between 1 and 150 MeV are considered, using X-ray spectra of active galaxies and SAS 2 data regarding the intensity upper limits to the gamma-ray emission above 35 MeV. It is found that a substantial increase in slope of the photon energy spectrum must occur in the low energy gamma-ray region for Seyfert galaxies, BL Lac objects, and emission line galaxies; the power-law spectra observed in the X-ray range must steepen substantially between 50 keV and 50 MeV. In addition, a cosmological integration shows that Seyfert galaxies, BL Lac objects, and quasars may account for most of the 1-150 MeV diffuse background, even without significant evolution.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 232
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    Magnetic Cepheids (1979)
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    Publication Date: 2011-08-17
    Description: The role of a magnetic field in the pulsational behavior of classical Cepheids has been studied by computing linearized models of pulsating stellar envelopes pervaded by a well-tangled magnetic field. It is found that the 'pulsational' masses of Cepheids that are implied by the theoretical values of the quantities Q(0), P(1)/P(0), and (possibly) P(2)/P(0) can be brought into line with the large 'evolutionary' masses, if the pressure due to the postulated magnetic field is assumed to be comparable to the thermodynamic pressure everywhere in the pulsating layers. The field strengths that are required - several hundred gauss at the surface and several ten thousand gauss at the base - are quite reasonable from the point of view of the observed magnetic fields in Cepheids. The influence of the magnetic field on the location of the blue edge of the instability strip in the H-R diagram is estimated to be very slight.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 234
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  • 33
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    On the origin of asteroids (1979)
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    Publication Date: 2011-08-17
    Description: A general scenario is described for the early history of the solar system. The primitive solar nebula is formed from the infall of gas from a collapsing interstellar cloud fragment. It becomes repeatedly unstable against collapse to form giant gaseous protoplanets. In the course of protoplanet evolution the center of the protoplanet enters a thermodynamic regime in which common rocky minerals become liquids; convection brings solids to the central region where a substantial fraction of them rain out to form a protoplanetary core. In the inner solar system protoplanetary envelopes are tidally stripped away, thus injecting into the solar nebula large equantities of chondrules and inclusions. Late in the development of the solar nebula, after most of the gas has disappeared, turbulence dies out and the small solids settle into a thin layer at midplane of the nebula. Gravitational instabilities in this layer form asteroidal and cometary bodies. Some further consequences of this scenario are discussed.
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    Geochemical evolution of the eucrite parent body - Possible nature and evolution of asteroid 4 Vesta (1979)
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    Publication Date: 2011-08-17
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    Infrared spectral reflectances of asteroid surfaces (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: This review compares the types of compositional information produced by three complementary techniques used in infrared observations of asteroid surfaces: broadband JHKL photometry, narrow band photometry, and multiplex spectroscopy. The high information content of these infrared observations permits definitive interpretations of asteroid surface compositions in terms of the major meteoritic minerals (olivine, pyroxene, plagioclase feldspar, hydrous silicates, and metallic Ni-Fe). These studies emphasize the individuality of asteroid surface compositions, the inadequacy of simple comparisons with spectra of meteorites, and the need to coordinate spectral measurements of all types to optimize diagnostic capabilities.
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    The nature and effects of impact cratering on small bodies (1979)
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    Publication Date: 2011-08-17
    Description: Collisions between asteroids and other forms of solar system debris are discussed, especially relatively high-energy, non-catastrophic collisions, the resulting craters, and the effects they should have on the surfaces and interiors of target bodies. Attention is given to the nature and formation of impact craters, as well as to shock waves and the energy (kinetic, internal) imparted through them, crater scaling, stress wave-surface interactions, impact melt, and the effects of non-escaping ejecta on the surface of the target body (rock, fine-grained regolith, porous media).
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Regolith development and evolution on asteroids and the moon (1979)
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    Publication Date: 2011-08-17
    Description: Early descriptions of regoliths on small bodies were devised to account for observations of asteroids (Chapman 1971, 1976) and the gas-rich meteorites (Anders 1975). Lack of agreement between these approaches prompted Housen et al. (1978, 1979) to examine the problem in detail. The resulting model predicted that moderate-sized (100-300 km) asteroids should evolve regoliths up to a few kilometers deep which could be source regions of gas-rich meteorites. Smaller objects should have regoliths ranging from dust coatings to meters-thick layers depending on the strength of the object. The earlier model could not treat asteroids larger than 300 km in diameter. The model, now modified to treat larger-sized objects, predicts regolith depths, on asteroids larger than 300 km, which decrease with increasing size. A regolith depth of 7 m is predicted for the lunar maria in reasonable agreement with the observed depths of 5 m.
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    Distant asteroids and outer Jovian satellites (1979)
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    Publication Date: 2011-08-17
    Description: Sixty percent of the sampled objects in the Hilda, Trojan and outer Jovian satellite locations belong to C-type and another 30% belong to a new group called RD-type (reddish and dark), sometimes referred to simply as D-type. Objects in this group have low albedo values between 2 and 4% and steep reflection spectra between 0.7 micron and 0.9 micron. Furthermore, 944 Hidalgo belongs to this group but shows color variation over its surface. Meteoritic minerals with similar optical reflection spectra are discussed. Trojans with sizes down to 15 km in the cloud preceding Jupiter are about 3.5 times more numerous than those in the following cloud. RD-type Trojans appear more often in the preceding cloud. There is a resemblance of spectrum, albedo and phase relation among the majority of Trojans and the outer Jovian satellites.
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  • 39
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    HEAO 1 observations of the X-ray pulsar 4U 1626-67 (1979)
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    Publication Date: 2011-08-17
    Description: Results are reported for an observation of the 7-s pulsar 4U 1626-67 with the A-2 experiment on HEAO 1. The phase-averaged X-ray spectrum between 0.7 and 60 keV is complex, as are the constituent spectra, which change radically as a function of pulse phase. Included in this spectral change is the sudden appearance and subsequent decay of a continuum or emission feature with a mean energy of 19 keV, which contains about one-half the power in this spectral range. Pulse-timing results include a new determination of the pulse period and a factor of 8 reduction in the upper limit for the light travel time for orbital periods between 1 and 7 hours. These findings are discussed and compared with the general nature of pulsar spectra.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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  • 40
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    Rb-Sr age of the Shergotty achondrite and implications for metamorphic resetting of isochron ages (1979)
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    Publication Date: 2011-08-17
    Description: The age of the Shergotty achondrite is determined by Rb-Sr isotope analysis and the metamorphic resetting of isochron ages, which is presumed to have occurred during a shock event in the history of the meteorite, is discussed. The isochron best fitting the Rb-Sr evolution diagram is found to correspond to an age of 165 million years, with an initial Sr-87/Sr-86 value of 0.72260. Different apparent ages obtained by the K-Ar and Sm-Nd methods are interpreted in terms of a model which quantifies the degree of resetting of internal isochron ages by low temperature solid state diffusion. On the basis of these considerations, it is concluded that Shergotty crystallized from a melt 650 million years ago, was shock heated to 300 to 400 C after its parent body was involved in a collision 165 million years ago, and was first exposed to cosmic rays two million years ago.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta; 43; July 197
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  • 41
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    Statistical equilibrium in cometary C2. II - Swan/Phillips band ratios (1979)
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    Publication Date: 2011-08-17
    Description: Statistical equilibrium calculations have been made for both the triplet and ground state singlets for C2 in comets, using the exchange rate as a free parameter. The predictions of the results are consistent with optical observations and may be tested definitively by accurate observations of the Phillips and Swan band ratios. Comparison with the one reported observation indicates compatibility with a low exchange rate and resonance fluorescence statistical equilibrium.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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    Voyager spacecraft radio observations of Jupiter - Initial cruise results (1979)
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    Publication Date: 2011-08-17
    Description: Low frequency (below 1326 kHz) observations of Jupiter obtained from November, 1977 through June, 1978 by the radio astronomy receivers carried by the two Voyager spacecraft are reported and compared with a large body of higher-frequency ground-based observations. Although the morphology of hectometric wavelength (HOM) emissions strongly resembles that of decametric (DAM) wavelength radio noise, they display opposite polarization. DAM emissions are strongly modulated by Io, whereas HOM emissions exhibit little or no influence from any satellite and appear to be modulated by the rotation phase of the planet. Several single-source models could possibly account for these results, including a model assuming emission at two well-separated frequencies above and below the local electron plasma frequency and the model proposed by Barbosa (1976) in which electrostatic waves at twice the upper hybrid frequency couple to both the ordinary and extraordinary electromagnetic modes. However, neither of these is entirely satisfactory.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters; 6; June 197
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  • 43
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    Pioneer 10 studies of interplanetary shocks at large heliocentric distances (1979)
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    Publication Date: 2011-08-17
    Description: Pioneer 10 Ames plasma analyzer data collected in the 6.1 to 12.6 AU range of heliocentric distances (November 1974 to April 1977) have been examined for interplanetary shock waves. Eighteen shock signatures have been identified, with four of these being of the reverse type and the remainder the forward type. Sonic Mach numbers in the range from 3 to 10 are estimated for these events.
    Keywords: ASTROPHYSICS
    Type: Geophysical Research Letters; 6; June 197
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    Discovery of two distorted interstellar bubbles (1979)
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    Publication Date: 2011-08-17
    Description: During an extensive program of direct imagery of emission nebulae, arcuate structures have been found around two stars. A well-defined shocklike structure is found about the T Orionis variable LL Ori, located to the side of the Orion Nebula. A less extensive shocklike structure is also found about the runaway star Zeta Oph. These structures can be best described in terms of distorted interstellar bubbles. A direct consequence of this interpretation is an independent estimate of the rates of mass loss for these stars.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 23
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    An upper limit for the total energy of relativistic particles contained in the early stages of supernova explosions (1979)
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    Publication Date: 2011-08-17
    Description: A model is proposed for the emission of X-rays from supernova explosions wherein the thermal distribution of photons from a supernova photosphere is inverse Compton scattered by relativistic electrons within or near the surface of the star. Using this model, upper limits for the number of relativistic electrons and their total energy are established on the basis of upper limits to the observed X-ray luminosity of a supernova during maximum light. These upper limits, in conjunction with radio frequency upper limits obtained by Brown and Marscher, strongly suggest that supernovae do not produce significant numbers of relativistic particles until at least 70 years after the initial outburst. This, in turn, implies that young supernovae cannot account for the radio and X-ray variability of active galactic nuclei and quasars.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 230
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    Gamma rays from accretion onto rotating black holes (1979)
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    Publication Date: 2011-08-17
    Description: Ionized matter falling onto an isolated rotating black hole will be heated sufficiently that proton-proton collisions will produce mesons, including neutral pions, which decay into gamma rays. For massive (1000-solar mass) black holes, the resulting gamma-ray luminosity may exceed 10 to the 36th erg/s with a spectrum peaked near 20 MeV.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 74; 1, Ap; Apr. 197
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    Sporadic mass ejection in red supergiants (1979)
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    Publication Date: 2011-08-17
    Description: A general mechanism first proposed by Burke (1969) is applied to red supergiants for determining the spin-down rate and angular-momentum loss of rotating stars. This model relies principally on sporadic mass ejection, which is assumed to be the result of turbulent elements accelerating material in cool supergiant atmospheres. Mass is preferentially expelled in the forward direction of rotation, resulting in a rapid loss of angular momentum on time scales of 10,000 to 1 million years in the supergiant evolutionary phase. Such rotational breaking will occur if the turbulent elements have characteristic sizes a few percent of the stellar radius and rms velocities one-third the escape speed of the star. This model predicts the formation of a cool silicate disk or torus around the star because of the preferred expulsion of material near equatorial regions of the supergiant.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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    Absorption models for low-frequency variability in compact radio sources (1979)
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    Publication Date: 2011-08-17
    Description: The consequences of the most plausible version of the absorption model for low-frequency variability in compact extragalactic radio sources are considered. The general restrictions placed on such a model are determined, and observational tests are suggested that can be used either to support the model or to discriminate among its various versions. It is shown that low-frequency variability in compact radio sources can be successfully explained by a class of models in which the flux is modulated by changes in free-free optical depth within an intervening ionized medium. Two versions of such a model are distinguished, one involving large changes in optical depth and the other, small changes. It is noted that while absorption effects are capable of causing rapid flux and structural variations at centimetric wavelengths, the models predict detailed behavior that is in direct conflict with observational data.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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    Comptonization of X-rays by low-temperature electrons (1979)
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    Publication Date: 2011-08-17
    Description: A method is described for calculating the spectrum that results from the Compton scattering of a monochromatic source of X-rays by low-temperature electrons, both for initial-value relaxation problems and for steady-state spatial diffusion problems. The method gives an exact solution of the inital-value problem for evolution of the spectrum in an infinite homogeneous medium if Klein-Nishina corrections to the Thomson cross section are neglected. This, together with approximate solutions for problems in which Klein-Nishina corrections are significant and/or spatial diffusion occurs, shows spectral structure near the original photon wavelength that may be used to infer physical conditions in cosmic X-ray sources. Explicit results, shown for examples of time relaxation in an infinite medium and spatial diffusion through a uniform sphere, are compared with results obtained by Monte Carlo calculations and by solving the appropriate Fokker-Planck equation.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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    Io - An intense brightening near 5 micrometers (1979)
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    Publication Date: 2011-08-17
    Description: Spectrophotometric observations of the Jovian satellite Io on February 20 and 21, 1978, (Universal Time) were made from 1.2 to 5.4 micrometers. Io's brightness at 4.7 to 5.4 micrometers was found to be three to five times greater at an orbital phase angle of 68 deg than at orbital phase angles of 23 deg (5.5 hours before the brightening) and 240 deg (20 hours after the brightening). Since the 5-micrometer albedo of Io is near unity under ordinary conditions, the observed transient phenomenon must have been the result of an emission mechanism. Although several such mechanisms were examined, the actual choice is not clear.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 16
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    Encounter with Venus (1979)
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    Publication Date: 2011-08-17
    Description: The orbiter and multiprobe components of the Pioneer Venus mission are briefly described. The orbiter was launched on May 20, 1978 and was placed into a highly eccentric near-polar orbit around Venus on December 4, 1978, while the multiprobe was launched on August 8, 1978 and reached Venus on December 9, 1978. Parameters of the orbiter orbit are presented, and modifications of the periapsis altitude are described. The time sequences of the probe entry events are reported for the large probe, north probe, day probe, and night probe, which, along with the bus, are the components of the multiprobe. The multiprobe entry and impact locations as well as related data are reported.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 23
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    Photoneutrino reactions in a superstrong magnetoactive plasma (1979)
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    Publication Date: 2011-08-17
    Description: The neutrino luminosity due to the photoneutrino process in the presence of a superstrong magnetoactive electron plasma appropriate for neutron stars is computed. The results indicate that for relatively low temperatures, between 100 million and 500 million K, the energy loss rate is significantly reduced both in the low-density regime below about 10 million g/cu cm (by the magnetic field) and in the high-density regime above that value (by plasmon excitations). These effects are temperature dependent, and they are less pronounced when the temperature is in the range from 500 million to 1 billion K.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 227
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    Venus upper atmosphere neutral composition - Preliminary results from the Pioneer Venus orbiter (1979)
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    Publication Date: 2011-08-17
    Description: Measurements in situ of the neutral composition and temperature of the thermosphere of Venus are being made with a quadrupole mass spectrometer on the Pioneer Venus orbiter. The presence of many gases, including the major constituents CO2, CO, N2, O, and He has been confirmed. Carbon dioxide is the most abundant constituent at altitudes below about 155 kilometers in the terminator region. Above this altitude atomic oxygen is the major constituent, with O/CO2 ratios in the upper atmosphere being greater than was commonly expected. Isotope ratios of O and C are close to terrestrial values. The temperature inferred from scale heights above 180 kilometers is about 400 K on the dayside near the evening terminator at a solar zenith angle of about 69 deg. It decreases to about 230 K when the solar zenith angle is about 90 deg.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 23
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    Electron temperatures and densities in the Venus ionosphere - Pioneer Venus orbiter electron temperature probe results (1979)
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    Publication Date: 2011-08-17
    Description: The Pioneer Venus orbiter electron temperature probe was used to obtain altitude profiles of electron temperature and density in the ionosphere of Venus. Elevated temperatures at times of low solar wind flux might indicate support for a certain model. According to this model, less than 5% of the solar wind energy is deposited at the ionopause and is conducted downward through an unmagnetized ionosphere to the region below 200 km where electron cooling to the neutral atmosphere proceeds rapidly. The patterns of electron temperatures and densities at higher solar wind fluxes are considered, the variability of the ionopause height in the late afternoon is noted, and the role of an induced magnetic barrier in the neighborhood of the ionopause is discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 23
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    Detection of HC/O-18//plus/ in Sagittarius B2 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Line emission at 85.1 GHz attributed to the J equals 1-0 rotational transition of the formyl ion HC(O-18)(plus) has been detected in Sgr B2 (OH). The double isotopic ratio (O-16/O-18)/(C-12/C-13) in the formyl ion in Sgr B2 is estimated to be in the range 5-10, hence within a factor 2 of the terrestrial value of 5.5. This determination implies that the C-13/C-12 ratio near the galactic center does not differ greatly from that in local molecular clouds.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 227
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    CO2 and CO electron vibrational cooling rates (1979)
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    Publication Date: 2011-08-17
    Description: Electron cooling rates for electron vibrational excitation of CO2 and CO and rotational excitation of CO are calculated. Results of the calculation are expressed as closed form analytic relations that are both convenient for numerical calculations and valid over a wide range of electron and neutral temperatures. It is found that the cooling rates and their temperature dependences differ significantly from other calculations. For CO2, these differences are related mainly to the assumptions about the approach to equilibrium and not to the actual cross-section choices. For electron temperatures below 1000 K and gas temperatures near 300 K (representative of conditions in the Venus atmosphere, where collisional cooling of the electrons dominates), the CO2 cooling rate is as much as an order of magnitude larger than previously considered in ionospheric models.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Nov. 1
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    Galactic distribution models of gamma-ray burst sources (1979)
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    Publication Date: 2011-08-17
    Description: The log N-log S relationships for several galactic distribution models of gamma-ray burst sources are derived. The resulting curves are substantially different from the galactic curves usually assumed (slope = -1). There is a relatively weak dependence on the radial distribution assumed but a strong dependence on scale height. Available observational data from several experiments appear to rule out both thin disk distributions and extended halo distributions which have a strong radial density dependence. The prospects are good for obtaining self-consistent distribution data from future large-area detectors.
    Keywords: ASTROPHYSICS
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    Scale covariance and G-varying cosmology. II - Thermodynamics, radiation, and the 3 K background (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Within the framework of a scale-covariant theory of gravitation, a semiclassical description of particles and photons is given. Thermodynamic relations consistent with the modified conservation equations are derived. Application to a system of radiation shows that the observed 3-K background radiation can be interpreted, within the present framework, as a remnant of equilibrium radiation in the past. As the theory postulates a nonstandard coupling between gravitation and electrodynamics, the assumption that Einstein's theory of gravitation is unchanged forces modifications at the atomic level. The use of Minkowskian spacetime in atomic physics is found to be adequate only over small, but not large, time scales compared with the age of the universe. As a result, a relation between energy and the frequency of a free photon is demonstrated. Possible observational consequences of this relation are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal Supplement Series; 41; Oct. 197
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  • 59
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    Large-scale structure of X-ray clusters of galaxies (1979)
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    Publication Date: 2011-08-17
    Description: Observations from the A-2 experiment on HEAO-1 are used to search for very large-scale structure (exceeding a degree) in 40 X-ray sources in clusters of galaxies. Significant evidence for extension is found only in the relatively nearby Perseus and Virgo clusters. For the remainder of the sources the results place stringent limits on the flux in any very large component.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 189
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  • 60
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    The violent interstellar medium (1979)
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    Publication Date: 2011-08-17
    Description: Observational evidence for high-velocity and high-temperature interstellar gas is reviewed. The physical processes that characterize this gas are described, including the ionization and emissivity of coronal gas, the behavior and appearance of high-velocity shocks, and interfaces between coronal gas and cooler interstellar gas. Hydrodynamical models for the action of supernova explosions and stellar winds on the interstellar medium are examined, and recent attempts to synthesize all the processes considered into a global model for the interstellar medium are discussed.
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  • 61
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    HEAO 1 observations of 4U1232+07 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An analysis of the NRL HEAO 1 observations of the Virgo cluster and 3C 273 has revealed X-ray emission from a region between these two objects. The most satisfactory explanation is the presence of two weak X-ray sources, for which error boxes have been obtained. One source is likely to be the peculiar galaxy IC 3576, suggested by Margon et al. (1972) as the source 2U 1231+07=4U 1232+07. The error box resulting from combining the present observations with the 4U data strengthen the X-ray identification with this extremely interesting galaxy. There are numerous possibilities for the other X-ray source, including the interacting pair of galaxies NGC 4410a and NGC 4410b (NGC 4410a/b).
    Keywords: ASTROPHYSICS
    Type: Nature; 281; Oct. 11
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  • 62
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    The magnetosphere of Mercury (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: According to Mariner 10 data on Mercury's magnetosphere, the bow shock and magnetosheath signatures in the magnetic field are entirely consistent with the geometry expected for interaction between a planet-centered magnetic dipole and the solar wind. The geometrically determined distance to the magnetopause stagnation point of solar wind flow was 1.45 plus or minus 0.15 Mercury radii. Comparative scaling of the magnetosphere of Mercury to earth shows that Mercury itself occupies a much larger fraction of the magnetosphere than does the earth. While there is no evidence for the permanent existence of a trapped charged particle radiation belt, intense transient bursts of energetic electrons indicate that a local acceleration process must be active. It is reasonable to assume that this process occurs in the magnetic tail. The interior plasma features compare well with those in the earth's magnetosphere. Characteristic time scales for transient phenomena at Mercury should be reduced by a factor of about 20 in comparison with those on earth - i.e., a few minutes for substorms vs an hour at earth. The origin of the magnetic field is unclear.
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  • 63
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    Planetary geodesy (1979)
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    Publication Date: 2011-08-17
    Description: The results of investigations of the geodesy of the planets and their satellites conducted during the period 1975 - 1978 are surveyed. Analysis of the photographic data of Mercury taken by Mariner 10 have revealed the mass, oblateness, radius rotation period and density of the panet, and allowed the high-resolution mapping of the surface. Earth-based radar imagery has permitted the identification of large-scale topographic features on Venus. Knowledge of the gravitational field of Mars has been improved by Mariner 9 and Viking tracking data, and the global topography and geometric figure of Mars have been derived. Doppler and ranging tracking data from the Viking landers have provided data for the precise determination of Martian rotational dynamics and the topographic features and figures of Phobos and Deimos have been observed. Pioneer 10 and 11 data have yielded information on the mass, gravitational field and dynamic parameters of Jupiter. Discoveries of a satellite of Pluto and a set of rings around Uranus have been made, the rotation of Uranus and Neptune have been measured, and the geodetic properties of the rings and satellites of Saturn have been investigated. Future developments in planetary geodesy are expected from continued Viking data and the Pioneer Venus probe and Voyager probes to Jupiter and Saturn.
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  • 64
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    Cosmic ray ionization of the Jovian atmosphere (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An approximate form of the Boltzmann equation has been used to obtain local ionization rates due to the absorption of galactic cosmic rays in the Jovian atmosphere. It is shown that the muon flux component of the cosmic-ray-induced cascade may be especially important in ionizing the atmosphere at levels where the total number density exceeds 10 to the 19th per cu cm (well below the ionospheric layers produced by solar EUV). A model containing both positive and negative ion reactions has been employed to compute electron and ion number densities. Peak electron number densities of the order of 1000 per cu cm may be expected even at relatively low magnetic latitudes. The dominant positive ions are NH4(+) and CnHm(+) cluster ions, with n at least 2; it is suggested that the absorption of galactic cosmic-ray energy at such relatively high pressures in the Jovian atmosphere (M about 10 to the 18th to 10 to the 20th per cu cm) and the subsequent chemical reactions may be instrumental in the local formation of complex hydrocarbons.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 39; Sept
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  • 65
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    VV 5-32-63/64 - The 'supermassive double galaxy' in Abell 1775 revisited (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Spectroscopy is presented for galaxies in A 1775, the cluster containing VV 5-32-63/64, an apparent double galaxy which has long been considered a gravitationally bound system with supermassive components (10 to the 13th solar masses). However, this model has run afoul of recent radio observations, which detected an extremely long straight radio tail emanating from the eastern galaxy in the pair. The present observations indicate that if both galaxies are members of the same cluster, the cluster radial-velocity dispersion (1522 km/sec) is large enough to account for the velocity difference between the two VV galaxies (1650 km/sec). It is therefore suggested that the VV galaxies are not gravitationally bound and need not be supermassive. The large velocity dispersion measured for A 1775 also strains suggested velocity dispersion vs X-ray luminosity relations for clusters of galaxies, as A 1775 has not yet been detected at X-ray wavelengths.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 91
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  • 66
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    Infrared spectroscopy of stars (1979)
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    Publication Date: 2011-08-17
    Description: This paper reviews applications of IR techniques in stellar classification, studies of stellar photospheres, elemental and isotopic abundances, and the nature of remnant and ejected matter in near-circumstellar regions. Qualitative IR spectral classification of cool and hot stars is discussed, along with IR spectra of peculiar composite star systems and of obscured stars, and IR characteristics of stellar populations. The use of IR spectroscopy in theoretical modeling of stellar atmospheres is examined, IR indicators of stellar atmospheric composition are described, and contributions of IR spectroscopy to the study of stellar recycling of interstellar matter are summarized. The future of IR astronomy is also considered.
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  • 67
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    Martian meteorology (1979)
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    Publication Date: 2011-08-17
    Description: Viking mission results concerning the structure and dynamics of the Martian atmosphere are reviewed. The large-scale variability of pressure, temperature, and zonally averaged wind at the Lander sites is described, and small-scale phenomena involving the boundary layer and internal gravity waves are discussed. Observational evidence for the existence of transient planetary-scale waves, forced quasi-stationary waves, and thermal tides on Mars is examined. Atmospheric dynamics and properties of dust storms are considered, with emphasis on dust properties and distribution, the time evolution of planetwide dust storms, and dust-storm genesis and decay. Attention is also given to the nature of past Martian climates, the sizes and composition of volatile reservoirs, and volatile escape from the atmosphere.
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  • 68
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    Observed properties of interstellar dust (1979)
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    Publication Date: 2011-08-17
    Description: Recent information on the observed properties of interstellar dust is reviewed, with an attempt made to clarify some of the observational uncertainties associated with obtaining dust parameters. Attention is given to interstellar extinction, the interstellar dust distribution, the dust-to-gas ratio, and light scattering by dust grains. Interstellar polarization is also examined, along with heavy-element depletion in the interstellar medium, thermal emission from interstellar dust grains, diffuse interstellar features, and the composition and origin of interstellar grains.
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  • 69
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    Latitudinal beaming of Jupiter's low frequency radio emissions (1979)
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    Publication Date: 2011-08-17
    Description: Observations of Jupiter's radio emissions from Jovigraphic latitudes greater than 3.3 deg are reported. The measurements were obtained from the Voyager 2 spacecraft at declinations up to 6.5 deg, and when these results are compared with simultaneous observations from Voyager 1 near the ecliptic plane (at a Jovigraphic latitude of about 3 deg), they indicate that the latitudinal-beaming effects persist and may even become stronger with higher latitudes. The results were combined with earlier low-frequency measurements from periods with De as low as -3 deg in order to show the beaming effects the occurrence of the emission over a full 10 deg range of altitude. The results of observations at frequencies near 1 MHz are also discussed, which were obtained from Voyager 1 and 2 in 1978, Rae 1 in 1969, and Imp 6 in 1971-1972. The implications of the new results for models of Jupiter's radio-emission beam pattern are considered.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Sept. 1
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  • 70
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    Stellar magnetic fields - The role of a magnetic field in the peculiar M giant, HD 4174 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Principles of coronal heating via basic electrodynamic effects, viz., resonant absorption of Alfven surface waves (quiescent) and magnetic tearing instabilities (impulsive), are detailed to argue three principles which may have application to late-type evolved stars. First, if one observes that B-squared/8 pi is much greater than rho times v-squared in a stellar atmosphere, then the observed magnetic field must originate in an interior dynamo. Second, low mass-loss rates could imply the presence of closed magnetic flux loops within the outer atmosphere, which constrain hydrodynamic flows when the magnetic body forces exceed the driving forces. Third, given that such magnetic loops effect an enhancement of the local heating rate, a positive correlation is predicted between the existence of a corona and low mass-loss rates. Application of these principles is made in the case of the peculiar M giant star HD 4174, which is purported to have a kilogauss magnetic field. Several of its spectroscopic peculiarities are shown to be consistent with the above principles, and further observational checks are suggested. Possible application to dMe and RS CVn objects is sketched.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 91
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  • 71
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    The mean Jovian temperature structure derived from spectral observations from 105 to 630 cm kaysers (1979)
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    Publication Date: 2011-08-17
    Description: Far infrared observations of the thermal emission of Jupiter are used to determine the temperature at 1 bar. High-altitude observations of the whole-disk brightness temperature of Jupiter in the range of 100 to 347 kaysers were inverted to obtain a P-T profile between 1.5 and 0.06 atm, assuming as opacity sources the H2 collisionally induced continuum and the rotation inversion bands of ammonia. The P-T profile derived from the spectrum reproduces the main features of the observed spectrum, with a slightly improved fit if the effects of ammonia haze opacity or NH3 supersaturation in the saturated region are taken into account. The Jovian temperature is found to be 160 + or - 7 K at 1 bar, and 105 + or - 3 K at the inversion level at 0.15 bar. The 1-bar temperature is shown to be consistent with Jovian interior models which match the observed gravitational moment.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 40; Oct. 197
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  • 72
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    Physical parameter profiles of selected X-ray flares (1979)
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    Publication Date: 2011-08-17
    Description: Soft X-ray proportional-counter data for nine X-ray flares of class C1 to M1 occurring during the Skylab mission, have been analyzed to yield temperature, volume emission measure, electron density and thermal energy content. Profiles of these quantities are presented, using 1-min averages of 2.5-s resolution data. The event profiles are discussed and comparisons with previous studies made.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics Supplement Series; 38; Oct. 197
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  • 73
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    Pulse-phase spectroscopy of Hercules X-1 (1979)
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    Publication Date: 2011-08-17
    Description: The 6-18 keV and the 40-60 keV X-ray spectrum of Hercules X-1 were simultaneously observed with the A-2 experiment on HEAO-1. By combining these measurements with the results of an earlier observation of this X-ray pulsar, evidence was found for a component of emission above 40 keV which is above an extrapolation from lower energies, by a factor which depends on the phase of the pulse. These data were compared to previous hard X-ray observations and possible models were discussed.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 188
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  • 74
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    Cosmic far-ultraviolet background radiation - Probe of a dense hot intergalactic medium (1979)
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    Publication Date: 2011-08-17
    Description: Line and continuum radiation fluxes have been computed for a wide range of enriched intergalactic medium (IGM) models. Observations of the diffuse extragalactic light at optical and far-ultraviolet wavelengths are found to provide a potentially important probe of a dense hot intergalactic medium. If the diffuse X-ray background is produced by this gas, the models constrain the cosmological density parameter (Omega) to be less than 0.4. The associated Compton distortions of the cosmic blackbody background radiation and the optical depths to distant quasars at X-ray wavelengths are also evaluated.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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  • 75
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    Double core evolution and X-ray binaries (1979)
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    Publication Date: 2011-08-17
    Description: The evolution of a 16-solar mass star and a 1-solar mass neutron star is followed through the common-envelope binary phase. It is found that the encounter of the neutron star with a yellow giant leads to coalescence of the two cores, while encounter with a red giant leads to hydrodynamic expansion and probable ejection of the common envelope. Within the context of the two rotation laws (1) uniform rotation (investigated in the present study), and (2) uniform specific angular momentum (considered in an earlier study), the results are independent of the choice for the angular-momentum distribution in the common envelope. Implications of the results for the binary pulsar phase are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Letters; 20; 2, 19; 1979
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  • 76
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    Reversal of the /O III/lambda 4363/H sub gamma lambda 4340 ratio in the planetary nebula IC 4997 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Five image-tube spectrograms of the planetary nebula IC 4997 obtained during August 1977 show that the intensity forbidden ratio O III 4363 A/H-gamma 4340 A was equal to unity, but a sixth one obtained in April 1978 showed the ratio to be 0.91. These results represent a significant increase in the intensity ratio, which had been declining from 1895 to 1962 (when it was considerably less than unity), and is interpreted as resulting from a gradual increase in temperature of the nebula's central star accompanied by a transient event which led to a temporarily high value for the ratio in mid-1977.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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    X-ray observations of AM Herculis from OSO 8 (1979)
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    Publication Date: 2011-08-17
    Description: X-ray observations of the white dwarf binary system AM Herculis in the range 2 to 250 keV, taken by OSO 8, are presented and compared with balloon and Ariel 5 measurements. The composite spectrum of the 2 to 40 and 20 to 250 keV fluxes determined by the proportional counter and the high energy scintillation spectrometer, respectively, on board the satellite is shown averaged over the entire binary cycle. Variations in spectral shape and intensity between the OSO 8 results and balloon measurements taken 10 to 20 days apart are observed. Results indicate the presence of a spectral break at about 15 keV on some occasions, similar to that seen in Her X-1, however presumably caused by a different mechanism than in the neutron star. It is also considered unlikely that the gamma-ray tail observed by Ariel 5 existed during OSO 8 observations.
    Keywords: ASTROPHYSICS
    Type: Nature; 279; June 7
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  • 78
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    NGC 1275 /3C 84/ - Similar structure in the optical and 3-mm radio variations (1979)
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    Publication Date: 2011-08-17
    Description: Optical and 3.3-mm data for the Seyfert galaxy NGC 1275 (3C 84) are compared. Similarities exist between the variations at the two wavelengths with regard to amplitude, time scale, and interval between events. The question is raised whether these similarities may be the result of a common triggering mechanism.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 91
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  • 79
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    The magnetic fields of Mercury, Mars, and moon (1979)
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    Publication Date: 2011-08-17
    Description: Mariner observations have shown a significant global magnetic field at Mercury with a dipole moment at a tilt of 14 + or - 5 deg relative to the normal of the orbit plane. A presently active dynamo is the most likely origin for the planet's magnetic field. Limited evidence for an intrinsic magnetic field on Mars was obtained by USSR spacecraft in 1971 and 1974. The Martian magnetic field, if it exists, may result from either remanent magnetism or an active dynamo. On the moon, local magnetic fields have been detected by the Apollo and Lunokhod missions, but no global correlation of the steady state values has been noted.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 80
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    An analysis of the infrared continuum of comets. II - Comet Kohoutek (1979)
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    Publication Date: 2011-08-17
    Description: An analysis of the infrared observations of comet Kohoutek has been carried out on the basis of silicate grain models. The 'observed' grain temperature has been obtained as a function of the heliocentric distance, and it is compared with the expected distribution. In the visible region, one requires for the refractive index, (m = n-ik), n of about 1.6 and k less than 0.05. The total number of grains varies essentially as the inverse square of radial distance; the size of the particles in the antitail of the comet Kohoutek is greater than 5 microns. The ratio of infrared flux from grains to the incident solar flux at wavelengths of a few microns is calculated.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 84; May 1979
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  • 81
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    Cool stars - Effective temperatures, angular diameters, and reddening determined from 1-5 micron flux curves and model atmospheres (1979)
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    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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  • 82
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    Ionosphere of Venus - First observations of the dayside ion composition near dawn and dusk (1979)
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    Publication Date: 2011-08-17
    Description: Independent Bennett radio-frequency ion mass spectrometers on the Pioneer Venus bus and orbiter spacecraft obtained in situ measurements of the composition of the ionosphere of Venus. The spectrometer on the bus explored the dawn region while the spectrometer on the orbiter explored the duskside region. Information on the ion composition in the topside, the lower ionosphere, and the upper ionosphere is presented. Below the O(+) peak near 200 km, the ions are found to exhibit scale heights consistent with a neutral gas temperature of about 180 K near the terminator. In the upper ionosphere, scale heights of all species reflect the effects of plasma transport.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 23
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  • 83
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    Initial observations of the Pioneer Venus orbiter solar wind plasma experiment (1979)
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    Publication Date: 2011-08-17
    Description: The ionosphere, ionosheath, ionopause, and bow shock wave of Venus are characterized. Venus is found to have a well-defined strong standing bow shock wave. In the ionosheath, downstream from the shock, compressed and heated postshock plasma apparently interacts directly with the ionosphere. Plasma ion velocity deflections suggest that the ionopause has a blunt shape. The positions of the bow shock and ionopause are variable and appear to respond to changes in the external solar wind pressure.
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    Type: Science; 203; Feb. 23
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  • 84
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    Minor planets and related objects. XXVII - Lightcurves of 887 Alinda (1979)
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    Publication Date: 2011-08-17
    Description: Eleven light curves and UBV photometry of the Amor asteroid Alinda, a candidate for having a cometary origin, are analyzed. A probable rotation period of 73 h 58 m + or - 3 m (p.e.) is derived on the assumption of two maxima and two minima per cycle in a composite light curve. An absolute V magnitude of 14.10 + or - 0.08 and a phase coefficient of 0.042 + or - 0.003 mag/deg in V are obtained, along with a B-V color of 0.86 + or - 0.02 and a U-B color of 0.50 + or - 0.05, both extrapolated to zero phase. The rotation period is shown to be the longest yet observed for an asteroid. It is concluded that the colors of Alinda are not unusual for an asteroid, that Alinda is probably not an extinct cometary nucleus, that the slow rotation may be a consequence of one or more collisions, and that the pole of Alinda may be nearly perpendicular to the ecliptic.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astronomical Journal; 84; Feb. 197
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  • 85
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    Some simple properties of stellar pulsation modes (1979)
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    Publication Date: 2011-08-17
    Description: Except for the lowest harmonics, small-amplitude stellar pulsation modes possess many simple properties whose evaluation does not require numerical integration of the fourth-order equations of motion. All antinodes tend to have the same total kinetic energy except for those lying near physical or geometric boundaries. However, when kinetic energy per unit volume is considered, order-of-magnitude enhancements are seen in antinodes lying near the center of the star, and factor-of-2 enhancements occur near the polar axis. The nodes are distributed very regularly along the radius. They follow an exponential law in g-regions, and their separation is proportional to the sound travel time in p-regions. A simple graphical procedure is described for surveying the oscillation frequencies of a new stellar model. A precise condition is derived giving the division of energy between radial and angular motion. Another condition gives the fractional contribution to the velocity field of its two sources, the divergence and the curl. Certain simplifying results of weak coupling among the linear modes are briefly described.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 227
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  • 86
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    Theories of magnetospheres around accreting compact objects (1979)
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    Publication Date: 2011-08-17
    Description: The paper reviews theoretical models of magnetospheres formed around neutron stars and other strongly magnetized compact objects in the presence of mass accretion from a companion star. Emphasis is placed on the interaction of the accretion process with the magnetic field of the compact object and the formation of a magnetosphere. The following models are discussed: magnetospheres with polar funnels; closed magnetospheres and their instabilities; models of internal flow; and disk accretion magnetospheres.
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    The discovery of 38.22 second X-ray pulsations from the vicinity of OAO 1653-40 (1979)
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    Publication Date: 2011-08-17
    Description: A 38.22-s X-ray pulsator has been discovered during an 8-hour HEAO 1 pointed observation of the area of sky containing OAO 1653-40. It is found that this pulsing source is not associated with V861 Sco, the proposed optical identification for OAO 1653-40. The spectrum is very hard, the spectral index being about 1.4, with about a 500-eV equivalent width of iron-line emission. No high-energy cutoff is observed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 88
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    Scale covariance and G-varying cosmology. IV - The log N-log S relation (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The traditional radio counts N(S) and radio source models are studied within the framework of the scale-covariant cosmology developed to investigate whether the relative strength of the gravitational and electromagnetic constants is a function of cosmological epoch. It is found that a gravitational constant G varying as the inverse of t, where t is the epoch in atomic units, is consistent with all the data analyzed. For a wide class of models the present cosmology allows a finer discrimination of the deceleration parameter than does standard theory. The results, when combined with those of previous papers, namely, those from radio and optical flux and angular-diameter data analysis, favor an open universe.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal Supplement Series; 41; Oct. 197
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  • 89
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    Infrared methane spectra between 1120 per cm and 1800 per cm - A new atlas (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A new atlas of CH4 lines in the 1120-1800-per cm region has been generated, based on laboratory spectra taken with a Nicolet interferometer at 0.06-per cm resolution with 635-cm path length at pressures of 0.98 torr, 4.86 torr, and 19.97 torr. A compilation of line positions and line intensities includes 1339 CH4 lines, several hundred of which have not been previously observed.
    Keywords: ASTROPHYSICS
    Type: Applied Optics; 18; Nov. 15
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  • 90
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    Discovery of a new Jupiter satellite (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: During detailed analysis of Voyager 2 pictures of the Jupiter ring, a starlike object was identified in the plane of the ring. The same object was subsequently found on a higher-resolution frame and proved to be a satellite of Jupiter. This satellite has a circular orbit whose radius is 1.8 Jupiter radii, a period of 7 hours and 8 minutes, and a diameter of less than 40 kilometers. It is located at the outer edge of the Jupiter ring.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 206; Nov. 23
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  • 91
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    Radio emission from nova shells (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: This paper presents data from multifrequency radio observations of the novae HR Del 1967 and FH Ser 1970 made from June 1970 to December 1978 and of V1500 Cyg 1975 made from September 1975 to December 1978. The data for FH Ser and V1500 Cyg constitute a complete history of the important phases of their radio 'light' curves, while all but the rising portion of the optically thick phase of an expanding nova shell is present for HR Del. A simple solution of the spherically symmetric equations of mass and momentum conservation for an isothermal gas, for which pressure gradients are effectively decoupled from the dynamics, is shown to fit the radio data for all three novae quite well. The main features of this model are strong density and velocity gradients that lead to long periods when the 'observable' shell evolves from an optically thick 'disk' to a completely optically thin shell.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 84; Oct. 197
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  • 92
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    Search for X-ray emission from bursting radio sources (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Results are reported for a systematic search with the A-2 experiment aboard HEAO 1 for X-ray emission from 28 radio sources that were actually bursting at the epoch of the X-ray observations. Two of these sources are found to lie within the positional errors of X-ray sources: the moderately redshifted quasars NRAO 140 and NRAO 530. The positions of 30 historically variable radio sources that were not active at the time of the search are compared with those of detectable X-ray sources, but no X-ray emission is detected from any of these positions. The implications of the results are discussed in terms of models for the radio emission from compact extragalactic sources. Several possible explanations are presented for the general absence of Compton X-ray emission from the bursting radio sources surveyed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 93
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    The magnetic field of Mercury (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper examines the magnetic field observations and their analyses relating to the determination of the Mercury magnetic field. Methods of analyzing data included: (1) comparison of bow shock and magnetopause relative positions at Mercury to the earth, (2) direct spherical harmonic analysis, (3) magnetosphere modeling by an image dipole, and (4) scaling of a mathematical model for the terrestrial magnetosphere. Dipole moments were determined using partial quadrupole and octupole terms to improve the least-square fit of models to observations; analyses by method (2) yield a convergent series of dipole moments values considered to best represent the intrinsic planetary field. Finally, it is suggested that the origin of the magnetic field of Mercury cannot be uniquely determined, but the sources of convective energy may be radiogenic decay and heat release, gravitational settling, and differentiation of processional torques.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 94
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    Some new results on spherical dynamos (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Small-scale motions in the earth's liquid core are likely to be highly anisotropic because of the effects of rotation. Guided by physical considerations, the 'alpha-effect' described by an anisotropic tensor alpha sub ik is formulated and the corresponding boundary value problem for a sphere is solved for a variety of boundary conditions. A converged solution has been obtained only in the case of the Fermi condition of an infinitely conducting exterior of the sphere. Some remarks are made on the hypothetical upper bound on magnetic field strengths in planetary cores originally proposed by Busse (1976).
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 95
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    Long-term studies with the Ariel 5 ASM. II - The strong Cygnus sources (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The three bright 3-6 keV X-ray sources in Cygnus are examined for regular temporal variability with a 1300 day record from the Ariel 5 All-Sky Monitor. The only periods consistently observed are 5.6 days for Cyg X-1, 11.23 days for Cyg X-2, and 4.8 hours for Cyg X-3. The 78.4 day period of Kemp, Herman, and Barbour for Cyg X-1, the 9.843 day period of Cowley, Crampton, and Hutchings for Cyg X-2, and the 16.75 day period of Holt et al. for Cyg X-3 are not confirmed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 96
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    Thermonuclear runaways on neutron stars (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Thermonuclear runaways which develop when neutron stars of 0.476 solar masses accrete hydrogen-rich material at 10 to the -10th and 2 x 10 to the -9th solar masses/year have been followed using a numerical model. It is found that a thermal instability occurs at densities in excess of 10 to the 5th g/cu cm and that the maximum accumulated mass required to initiate the runaway is 0.7 x 10 to the -12th and 2.1 x 10 to the -12th solar masses for the mass accretion rates of 10 to the -10th and 2 x 10 to the -9th solar masses/year, respectively. Heating the of the neutron star envelope by hydrogen burning leads to the ignition of helium. The nonequilibrium burning of helium by a combination of (alpha, p), (p, gamma), and (alpha, gamma) reactions involving O-14, O-15, and other heavy nuclei provides the energy for an X-ray burst. The gross properties of these models bear suggestive resemblance to those observed for some X-ray burst sources.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 97
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    Intense interplanetary magnetic fields observed by geocentric spacecraft during 1963-1975 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: In the present paper, interplanetary magnetic field and plasma data are reviewed over a period exceeding one full solar cycle for intervals in which the magnetic intensity was greater than 13 gammas. One hundred forty nine intervals of this type, with almost complete plasma and magnetic field data, are identified. Most (79%) of these enhancements could be associated either with interplanetary shocks or with high-speed stream interfaces. Half of the remaining 21% of the enhancements could be identified as cold magnetic enhancements, while the other half could not be associated with a single shock, interface, or cold magnetic enhancement.
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research; 84; Nov. 1
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  • 98
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    The shape and location of the sector boundary surface in the inner solar system (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Simultaneous observations by Helios 1 and Helios 2 over four solar rotations, between January 20 and May 23, 1976, were used to determine the latitudinal dependence of the polarity of the interplanetary magnetic field within plus or minus 7.23 deg of the solar equator and within 1 AU. The longitudinal and latitudinal positions of the sector boundary crossing are consistent with a warped sector boundary which extended from the sun to 1 AU and was inclined approximately 10 deg with respect to the heliographic equator. This is consistent with simultaneous Pioneer 11 observations, which showed unipolar fields at approximately 16 deg latitude at heliocentric distances greater than 3.5 AU. Two sectors were observed at southern latitudes; however, four sectors were observed at northern latitudes on two rotations, indicating a distortion from planarity of the sector boundary surface.
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research; 84; Nov. 1
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  • 99
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    Io's surface and environs - A magmatic-volatile model (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A model is proposed to account for the observed properties of Io. The crust is probably siliceous, but the outermost visible surface is composed primarily of several allotropes of elemental sulfur, plus frosts of SO2, H2S, and S2O. The 4-micron feature in Io's IR reflectance is identified as the (nu 1 + nu 3) band of SO2 frost. A possible source of the S is dissociation of iron sulfide brought up from the core by mantle convection. The SO2 is produced in the volcanoes, and the H2S by interaction of magnetospheric protons with the surface S. Delayed luminescence from S2O could cause the posteclipse brightening. The orbital torus is sustained by evaporation from molten ejecta from the volcanoes. Several additional diagnostic absorption bands and two additional minor torus species are predicted by this model.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters; 6; Oct. 197
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  • 100
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    The dynamics and stability of radiatively driven gas clouds. I - Plane-parallel slabs (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A combination of numerical and analytical techniques has been used to investigate the dynamics and stability of optically thin plane-parallel radiatively driven slabs of gas confined by the thermal gas pressure of a high-temperature low-density medium. Scaling laws allow the individual model 'clouds' to be characterized by a single free parameter, chi, a normalized column density which measures the strength of the acceleration due to radiation pressure relative to that due to thermal gas pressure. It is found that these clouds are stable and coherently accelerated only when chi is small. In this regime a simple slab model is constructed which accurately reproduces the more complex gasdynamic results. The low-chi clouds are marginally able to reach the high velocities seen in the atmospheres of quasi-stellar objects, but only if their motion is subsonic with respect to the external confining medium. This implies either that the medium is extremely hot and tenuous or that it is moving outward with the clouds.
    Keywords: ASTROPHYSICS
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