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  • Chemistry  (5,931)
  • ASTROPHYSICS  (379)
  • SOLAR PHYSICS  (256)
  • 1995-1999
  • 1980-1984
  • 1975-1979  (6,566)
  • 1925-1929
  • 1978  (6,566)
Collection
Keywords
Publisher
Years
  • 1995-1999
  • 1980-1984
  • 1975-1979  (6,566)
  • 1925-1929
Year
  • 1
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    Picosecond chemical and biological events (1978)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1978-10-13
    Description: Picosecond spectroscopy is a relatively new field of science that utilizes ultrashort laser pulses to monitor events taking place in the 10(-12) second regime. The continuing development of picosecond spectroscopy has made possible the detection and measurement of the primary events in many physical and tiological processes. This article describes a currently used picosecond spectroscopy system that is capable of reliably recording picosecond events. Two areas of picosecond research are discussed; one concerns the interaction of electrons in fluids, and the second the primary events in vision.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rentzepis, P M -- New York, N.Y. -- Science. 1978 Oct 13;202(4364):174-82.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/694523" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; Electrons ; *Kinetics ; Lasers ; Protons ; *Retinal Pigments ; *Rhodopsin ; Spectrum Analysis/*methods ; Temperature ; *Vision, Ocular
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 2
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    Foreign aid support of science and economic growth (1978)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1978-03-17
    Description: The history of U.S. foreign aid support of science and technology in Latin America is examined and an attempt is made to evaluate the scientific and economic growth of that area in relation to the total foreign aid effort.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Szmant, H H -- New York, N.Y. -- Science. 1978 Mar 17;199(4334):1173-82.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/415363" target="_blank"〉PubMed〈/a〉
    Keywords: Chemistry ; Cost-Benefit Analysis ; Education ; History, 20th Century ; International Educational Exchange ; Latin America ; *Research Support as Topic ; *Science/history ; United States
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
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    The glycosylation of hemoglobin: relevance to diabetes mellitus (1978)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1978-04-07
    Description: Glucose reacts nonenzymatically with the NH2-terminal amino acid of the beta chain of human hemoglobin by way of a ketoamine linkage, resulting in the formation of hemoglobin AIc. Other minor components appear to be adducts of glucose 6-phosphate and fructose 1,6-diphosphate. These hemoglobins are formed slowly and continuously throughout the 120-day life-span of the red cell. There is a two- to threefold increase in hemoglobin AIc in the red cells of patients with diabetes mellitus. By providing an integrated measurement of blood glucose, hemoglobin AIc is useful in assessing the degree of diabetic control. Furthermore, this hemoglobin is a useful model of nonenzymatic glycosylation of other proteins that may be involved in the long-term complications of the disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bunn, H F -- Gabbay, K H -- Gallop, P M -- New York, N.Y. -- Science. 1978 Apr 7;200(4337):21-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/635569" target="_blank"〉PubMed〈/a〉
    Keywords: Blood Glucose/metabolism ; Chemical Phenomena ; Chemistry ; Diabetes Complications ; Diabetes Mellitus/*blood/diagnosis ; Diphosphoglyceric Acids/blood ; Glycosides/blood ; Glycosuria/etiology ; Hemoglobin A/*metabolism ; Hemoglobins/*analysis/*metabolism ; Humans ; Kinetics ; Oxygen/blood ; Structure-Activity Relationship
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 4
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    European Space Agency studies of the solar probe (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The feasibility and scientific objectives of a solar probe were studied by a Mission Definition Group in 1975 and 1976. The orbit analysis program was developed and an extended study of the orbit analysis was done in 1977. The results of these studies are in the Report of the Mission Definition Study (1976) and an E.S.O.C. report (1978), and the reader is referred to these sources for greater details. In this report, only brief discussion on mission concept and objectives, satellite design, orbit, orbit analysis, are presented.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 556-564
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  • 5
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    Solar probe study (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Realistic options for a Solar Probe Mission consistent with known technical, fiscal, and programmatic constraints are identified. A program plan for NASA which includes identification of necessary research and development activities is developed. A baseline mission and a strawman spacecraft design were selected and used to determine the feasibility of meeting the mission requirements and the sensitivity to variations in those requirements.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 521-534
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  • 6
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    Detection of gravitational radiation and oscillations of the sun via Doppler tracking of spacecraft (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The magnitude of Doppler signals produced by gravitational wave burst, continuous gravitational waves, and oscillations of the sun interacting with a spacecraft are considered. Expressions are worked out for the appropriate noise entering each measurement. The noise sources considered are the Doppler extractor, fluctuations in the solar wind and the troposphere, and fluctuations in the reference oscillator.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 498-517
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  • 7
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    Gravitational wave detection with the solar probe. II. The Doppler tracking method (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: How gravitational radiation affects Doppler tracking is briefly described. The status of the analyses of the sensitivities achievable with the NASA-JPL Deep Space Network(DSN) is given.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 441-449
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  • 8
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    What is the fate of interplanetary dust (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The following general picture of the interplanetary dust is presented: (1) size distribution; (2) spatial distribution; (3) composition; (4) dynamics; and (5) origin. The solar probe mission provides a unique opportunity to study the evolution of the interplanetary dust and its eventual destruction near the sun. Two destructive processes (fragmentation and vaporization) of interplanetary dust are discussed.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 411-419
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  • 9
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    The solar probe and coronal dynamics (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The discovery of coronal holes led to basic changes in ideas about the structure of the low corona and its expansion into the solar wind. The nature of the energy flux is not understood. Current ideas include enhanced thermal conductivities, extended MHD wave heating, and wave momentum transfer, all in rapidly diverging geometries. There is little feel for the relative importance of these processes. The Solar Probe, with its penetration deep into the solar corona, could lead to observational constraints on their relative importance, and thus to an understanding of the origin of the solar wind. Observations from the Solar Probe will also bear on such questions as to whether small scale "intrastream" structure is common close to the Sun in open field-line regions, whether the properties of the wind are pronouncedly different over closed and open field-line regions at five solar radii, and many others. The resolution of these questions requires measurements of the magnetic field and of the proton and electron distribution functions.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 318-333
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  • 10
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    Plasma waves near the sun: Advances possible with a solar probe (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A review is presented of current experimental and theoretical knowledge of plasma waves in the solar wind, with comments on the scientific importance of obtaining plasma wave measurements in the region near the sun with the solar probe. The waves discussed include the acoustic waves and shocks which are thought to be the primary source for heating the solar corona, Alfven waves, ion-cyclotron waves, whistler-mode turbulence, ion-acoustic waves, and electron plasma oscillations associated with solar radio emissions. A discussion is presented of the types of measurements which would be needed to study these waves on the solar probe, the constraints imposed on the spacecraft and the research and development which would be needed to provide the necessary instrumentation.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 281-317
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  • 11
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    Probing the solar corona with energetic particles (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Representative sets of recent experimental results and theoretical studies are summarized to show the current knowledge of energetic particle phenomena based mainly on observations near 1 AU. Measurements close to the sun of quantities such as particle spectra, charge and isotopic composition, and the flow of particles as a function of time, together with measurements of the plasma, magnetic field, X-rays, and gamma rays will not only reveal the properties of the source region and acceleration mechanisms but will also provide a better knowledge of the physics of the corona. These measurements may also reveal the existence of large scale inhomogeneities in the solar corona. The general requirements for making these measurements on the solar probe are listed. An energetic particle detector system which has the capability of resolving the charge and isotopic composition up to 50 MeV/nucleon may successfully measure the above quantities provided that it can perform under both very low and average intensity levels.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 205-218
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  • 12
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    Multicolor imaging and photopolarimetry: Disk features, K and F coronas, zodiacal light (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The unique vantage points and viewing geometries afforded by a close-in solar probe are briefly examined with regard to line and continuum measurements of features on the solar disk, the K and F coronas, and the zodiacal light. Common instrument and observing requirements are identified, suggesting that a single instrument could provide much of the necessary observational data on these phenomena.
    Keywords: SOLAR PHYSICS
    Type: JPL A Closeup of the Sun; p 143-154
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  • 13
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    Ion drive performance and trajectories (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The use of Solar Electric Propulsion (SEP) for the Solar Probe Mission is addressed. The dependence of the payload mass on the site of the SEP and the flight time are described on the basis of preliminary data. The range of hardware expected to be available in the 1980's is summarized. There are several classes of optimal low-thrust trajectories for the Solar Probe Mission. These are trajectory types A, B, C corresponding to one, two, or three orbital revolutions, respectively. Plots of transfer trajectories corresponding to type-A, type-A with a Venus Swingby, type-B, and type-C with ab Icarus Rendezvous are shown. A summary of the SEP performance is given.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 544-555
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  • 14
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    Zodiacal light dynamics experiment: A wideband imaging Fabry-Perot interferometer (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The Solar Probe will provide an ideal platform from which to study dynamics of dust particles near the sun by measuring the detailed character of the Fraunhofer structure of the zodiacal light. The suggested instrument is a wideband imaging Fabry-Perot interferometer with state of the art technology in both the optics and the detector. The instrument would function as a high-resolution imaging device providing wavelength resolution of 0.03 A over about a 20 A range. The wideband imaging capability would provide sky maps of the zodiacal light on a despun spacecraft without mechanical scanning. The Solar Probe mission would allow the velocity distribution of the dust to be mapped along most of the trajectory of the spacecraft.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 420-429
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  • 15
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    A solar wind experiment for the solar probe mission (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Electron and ion plasma measurements on Solar Probe are important, especially to elucidate the role of coronal holes as sources of the solar wind and to resolve the long debated question of the importance of wave heating within 20 solar radii to the acceleration of the solar wind. Adaptable instruments are required to cover the large dynamic range of parameters between 1 AU and 4 solar radii. The baseline mission would be improved, in some respects, by the addition of a second spacecraft, following the first by a distance of several solar radii. A spinning spacecraft would be satisfactory, but not essential, for the present objectives. Attention should be paid to having the heat shield electrically conducting. An instrument for ion and electron (but no composition) measurements would have a mass of approximately 10 kg, require 8 w of power, and generate data at a maximum rate of approximately 2 kbits/sec.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 345-353
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  • 16
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    Acceleration and heating of the solar wind (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Some of the competing theories of solar wind acceleration and heating are reviewed, and the observations that are required to distinguish among them are discussed. In most cases what is required is measurement of plasma velocity and temperature and magnetic field, as near the sun as possible and certainly inside 20 solar radii; another critical aspect of this question is determining whether a turbulent envelope exists in this inner region, and if so, defining its properties. Plasma and magnetic observations from the proposed Solar Probe mission would thus yield a quantum jump in our understanding of the dynamics of the solar wind.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 334-344
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  • 17
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    On neutrons from the sun (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A survey of all the experiments carried out over the past decade to verify theoretical predictions for the observation of solar neutrons is presented and discussed. The conclusions drawn from this discussion are: (1) the Solar Probe Mission is important in order to discover the low energy neutrons of solar origin; (2) this discovery is likely to carry very useful information about the nature, the locale, the lifetime and the mode of operation of the acceleration processes in the solar atmosphere; and (3) this information will lead to a rapid development of the science of solar meteorology and the more rapid forecasting of solar activity, on a long-term basis.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 262-270
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  • 18
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    Hard X-ray imaging from the solar probe (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The solar probe offers a platform with particular advantages for studying solar nonthermal plasma processes via the observations of hard X-radiation from energetic electrons in the chromosphere and corona, these include (1) high sensitivity, (2) a second line of sign (in addition to the earth's) that can aid in three dimensional reconstruction of the source distribution, and, (3) the possibility of correlation with direct measurements of the nonthermal particles from the probe itself.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 132-142
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  • 19
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    High resolution stereoscopic X-ray imaging of coronal features during a solar probe flyby (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The possible role of solar probe mission in answering fundamental questions about the structure and heating of coronal loops is examined. The experimental technique consists of imaging 1-10 keV X-rays to give accurate temperature profiles of hot active regions and post-flare loops. A limitation on the interpretation of such pictures is that steroscopic reconstruction of the three dimensional arches requires many lines of sight. This kind of information can be provided only by a rapid solar flyby. In addition, the proximity to the sun will provide useful spatial resolution with compact instrumentation. The pictures thus obtained will provide crucial tests of theoretical models of coronal arches.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 111-117
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  • 20
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    Optical observations of the sun from a solar probe (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The spatial resolution of solar surface structure to ultimate limits with simple instrumentation. The logic is simple: a 10 cm aperture telescope at 4 solar radii resolves the equivalent of a five meter telescope in earth orbit. Given the ease of producing a diffraction limited 10 cm telescope and the difficulty of fabricating a diffraction limited 5 meter telescope, the performance of the small telescope could well be better. The telescope described complements planned solar orbiting telescopes in earth orbit and would need only a few arcs seconds of pointing.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 89-91
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  • 21
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    Possible measurements of J sub 2 and the sun's angular momentum with the solar probe (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The metric tensor is given for describing the dynamical effects of the sun on a solar probe and the gravitational redshift of a probe-based clock in a covariance analysis for the detectability of the solar quadrupole moment and the solar angular momentum. Unknown parameters were determined by least squares fit to the probe tracking data. A polar orbit was assumed with perihelion at 5 solar radii and with an earth-sun-probe angle of 135 deg at perihelion. Tracking was assumed to be Doppler only, with a basic uncertainity of .1 mm/sec in the radial velocity. A drag-free system which could reduce nongravitational forces below the level of 2 times 10 to the minus 12th power was found necessary to preserve this same level of accuracy. Both one way and two way Doppler were supposed in order to determine the gravitational redshift as well as the pure spacecraft dynamics.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 58-59
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  • 22
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    The analysis of high spatial resolution UV and X-ray images by computational modeling (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Very high resolution stereoscopic images of high temperature loop structures observed at UV and X-ray wavelengths in the solar corona can be used to understand physical processes in the corona. An existing computational model is described and sample results are given to demonstrate that computational modeling of coronal structures can indeed take advantage of very high resolution images. The sample results include the run of temperature and number density along a typical loop and the variation of the differential emission measure with temperature. The integration of the differential emission measure with temperature along a column commensurate with an instrument's spatial resolution is the relevant parameter obtained from UV and X-ray observations. The effects of loop geometry and energy input are examined.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 118-131
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  • 23
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    Determination of the structure and heating mechanisms of coronal loops from soft X-ray observations with the solar probe (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: High resolution soft X-ray imaging from the solar probe is justified in terms of the expected scientific returns which include the determination of the temperature and density structure of a coronal loop. The advantages of the grazing incidence telescope over the multiple pinhole camera are discussed. An instrument package is described which includes a grazing incidence mirror, a thermal prefilter, a three position filter wheel and a focal plane detector baselined as an 800 by 800 back-illuminated charge coupled device. The structural assembly together with the data processing equipment would draw heavily on the designs being developed for the Solar Polar Mission.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 94-110
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  • 24
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    Measurement of solar gravitational oblateness with gravity gradiometers (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A very high sensitivity rotating gravity gradiometer onboard the spacecraft is described for measuring the gravitational oblateness of the Sun during a solar probe mission. The proposed instrument would be a self-contained structure in a thermal-vacuum-magnetic shield in the shape of a cross, with a mass of 20 kg and arm length of 1.0 m and thickness of 0.1 m. The sensor inside would have a resonant frequency of 1/30 Hz, a mechanical Q of one million and would use gravitational radiation antenna technology to achieve a sensitivity of 6 x 10 to the minus 8th power Eotvos, which would provide a measurement of the solar oblateness to an accuracy of 1.5 to 6 x 10 to the minus 8th power. The gravity gradiometer will require a spinning spacecraft, so that it will not sense the spacecraft gravity fields, but the gradiometer does not need to be at the spacecraft center of mass, or even on the spacecraft spin axis. Major problem areas to be addressed are demonstration of the instrument sensitivity prior to flight and the measurement and compensation for any residual spacecraft angular rates.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 69-78
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  • 25
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    Comments on the drag-free control of a solar probe relativity mission (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A spacecraft going within 4 solar radii of the Sun experiences an acceleration up to .00005 g from solar radiation pressure, and significant (though smaller) accelerations from the solar wind. To obtain satisfactory information about relativistic effects and the Sun's quadrupole mass coefficient, these non-gravitational accelerations are either measured or compensated out by making the spacecraft drag free. A proof mass inside the spacecraft structure is shielded from the external forces, so that it follows a nearly ideal gravitational orbit, and a control system activates gas jets (or other translational forcers) to make the vehicle follow the mass. The problems are mechanizing the control laws and minimizing extraneous effects such as the self gravitational pull of the spacecraft. The extraneous forces can be averaged in one plane by having a spinning vehicle.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 60-68
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  • 26
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    Possible measurement of the coefficient of the second zonal harmonic of the sun's gravitational field with a solar probe (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The use of radio tracking of a solar probe to estimate accurately the coefficient of the second zonal harmonic of the sun's gravitational field was examined. Preliminary results indicate that the coefficient can be estimated with a standard error of 10 to the minus 8th power or less, provided that the probe is equipped with a suitable drag-free system to compensate for the effects of non-gravitational accelerations. For signal paths that pass near the sun, dual-band ranging to the probe can provide the tracking accuracy needed to insure that the standard of error is equal to or less than 10 to minus 8th power. The possibility of achieving such accuracy with a single-band radio uplink and a dual-band downlink is discussed.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 19-41
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  • 27
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    The importance of determining the solar quadrupole moment (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Current theoretical modelling of the sun is in difficulty. Additional observations must be made to place constraints on the plethora of conjectures that have been advanced to explain the low neutrino flux and to guide solar model builders in their search to understand the deep interior of the sun. A determination of the magnitude of the solar quadrupole moment, is one such constraint; it places limits on the density, angular velocity and magnetic field distributions inside the sun.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 11-18
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  • 28
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    The Solar Backscatter Ultraviolet (SBUV) and Total Ozone Mapping Spectrometer (TOMS) experiment (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The SBUV/TOMS is designed to measure the extraterrestrial ultraviolet solar irradiation and the solar ultraviolet radiation from the earth and its atmosphere. Methods to recover the ozone information from backscattered ultraviolet measurements are described. Mapping of the total ozone and 200 mb height fields is obtained.
    Keywords: SOLAR PHYSICS
    Type: The Nimbus 7 User's Guide; p 175-212
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  • 29
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    Radial and solar cycle variations in the solar wind phase fluctuation spectral index as determined from Voyager 1978 solar conjunction data (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Columnar spectral index information that has been extracted from a sizable volume of Voyager 1978 solar conjunction Doppler phase fluctuation data is presented. The Voyager 1978 results, when compared to similar information derived from the 1976 Helios and Viking Solar Conjunctions, lead to the following inferences: (1) there has been a significant change in the spectral index from 1976 to 1978; (2) there is continuing evidence that favors a slight (positive) correlation between the spectral index and the solar cycle; and (3) there is little or no evidence in support of a radial variation of the spectral index.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 59-65
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    Ballistic trajectories (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The only ballistic trajectory mode feasible for a close solar probe or for an orbit inclined approximately 90 degrees to the ecliptic is the Jupiter gravity assisted mode. A comparison of the trajectories of the Solar Polar and the Solar Probe Mission for 1983 launches is shown. The geometry of the solar encounter phase is practically the same for the 4.3 year orbit achieved by a Jupiter gravity assist and for a one year orbit. Data describing the geometry of an orbit with perihelion at 4 solar radii and aphelion at Jupiter are listed. The range of apparent directions of the solar wind if it is flowing radially outward from the Sun with a speed of either 150 or 300 km/sec is shown. The minimum sun-earth-probe angle during the solar encounter as a function of the earth-node angle and the orbital inclination is also shown. If the inclination is 60 degrees or more, the minimum SEP angle is not greatly different from the 90 degree value.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 521-534
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    Transmission media effects on precise Doppler tracking (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The effects of the transmission media - the earth's troposphere and ionosphere, and the solar wind - on precise Doppler tracking are discussed. The charged particle effects can be largely removed by dual frequency observations; however there are limitations to these corrections (besides system noise and/or finite integration times) including the effects of magnetic fields, diffraction, and differential refraction, all of which must be carefully evaluated. The earth's troposphere can contribute an error of delta f/f approximately 10 to the minus 14th power.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 450-456
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    Scintillation observations near the sun (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Results on the electron density spectrum, the random velocity and the mean velocity of the solar wind in the region from 5 to 100 solar radii are presented. Results are based on intensity scintillations of incoherent radio sources at different locations and different radio frequencies. The shape of the electron density irregularity spectrum is shown to be well modeled by a power law in wavenumber with a slope that abruptly steepens at higher wavenumbers. This two slope power law model is shown to have a break (defined as the wavenumber of the change of slope) that increases with decreasing distance from the Sun. The fractional random velocity is shown to be insignificant at distances of greater than 40 solar radii, but shows a steady increase with decreasing solar distance inside of 40 solar radii.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 388-396
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    Plasma density mapping in the solar wind through use of VHF radio to measure electron content (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: How the electron content between the Solar probe and the earth can be observed with a minimum of equipment and give a quantitative rationale for the use of a signal near 400 MHz to supplement the telecommunications signal is described. The emphasis is on the method of making content observations and on their value. While far from the Sun, the electron content is so low that the S-X dual-frequency system is insufficiently sensitive and a UHF system is optimum. As the probe approaches the Sun, the UHF may be disrupted by scintillation and the variations of the telecommunications signal must be used for the content measurement. By operating the suggested system in different modes as the solar distance changes, operation during the entire mission is possible.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 397-407
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  • 34
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    A timed-correlated four-link Doppler Tracking system (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Phase perturbations that occur in the following components of the one and two-way systems are considered: (1) one-way system (signal from A to B): station a oscillator - transmitter A antenna A - signal path - antenna B - receiver B station B oscillator - recording system B; (2) two-way system (signal from A to B back to A): station A oscillator - transmitter A - antenna A - signal path up - antenna B - transponder B - antenna B - signal path down - receiver A - station A oscillator - recording system A. A symmetrical one- and two-way system which can identify the place of origin of the fluctuation and quantify it so as to recover the unperturbed phase at a given moment of time by time-correlating the phase fluctuations obtained in the one- and two-way data taken at both stations is described
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 457-497
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    Gravitational wave detection with the solar probe: I. Motivation (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Questions are posed and answered through discussion of gravitational wave detection with the Solar Probe. Discussed are: (1) what a gravitational wave is; (2) why wave detection is important; (3) what astrophysical information might be learned from these waves; (4) status of attempts to detect these waves; (5) why the Solar Probe is a special mission for detecting these waves; (6) how the Solar Probe's expected sensitivity compares with the strength of predicted gravitational waves; and (7) what gravity wave searchers will do after the Solar Probe.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 433-440
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    Magnetohydrodynamic simulation of coronal mass ejections into the solar wind (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A state of the art fluid continuum technique to describe the MHD transient respose of the corona below 10 solar radii during two well observed events (flares on 21 August 1973 and 5 September 1973) is reviewed. It is concluded that the computer simulation should be subjected to in situ verification of as many of its initial assumptions as possible. Its ability to provide a rational basis for physical understanding of mass ejections suggests its use as one of the tools used in the planning and analysis of such encounter missions.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 367-387
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    Spectroscopic mapping of solar wind velocities (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: During the total solar eclipse of 1970, measurements of resonantly scattered Lyman-alpha radiation from the solar corona revealed a means to determine temperatures and densities in the solar corona beyond 1.5 R solar radii. A natural extension of this work is to use the Solar Probe to measure the spectral line profile of Lyman-alpha radiation backscattered toward the Sun from coronal regions between 4 R solar radii and 10 R solar radii. The backscattered profile would provide unique and quantitative determinations of the outlaw velocities of coronal material into the solar wind. Such information is of critical importance for understanding solar-wind formation and solar-terrestrial effects on the earth's climate. There is no known way to obtain this information without a Solar Probe-type mission.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 354-365
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    Solar wind science for a solar probe mission (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Scientific objectives for solar-wind investigations relevant to a Solar Probe mission are outlined and put in perspective. Information gained from the various possible measurements are also listed.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 273-280
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  • 39
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    Solar neutron spectroscopy near the sun (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: A brief note is summarized to show the importance of solar neutron observations for the advancement of phenomena crucial for solar physics, and to suggest the constraints which must be placed on the Solar Probe Mission for carrying out studies of this kind.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 243-261
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  • 40
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    Low-energy protons: Gradients in interplanetary space and distribution in the solar corona (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: First and second order anisotropy measurements are proposed as a tool for studying the coronal source function and interplanetary propagation of low energy protons. Optimum orbit and attitude requirements are suggested for a three telescope system. Some limitations with regard to the lower energy limit for a feasible set-up are discussed.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 234-239
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  • 41
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    Magnetic field measurements from the solar probe (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: An optical system for the solar probe is described as well as its capability for improvements in spatial resolution. A magnetograph for measuring the elementary flux tube and obtaining vector geometry field geometry offers the possibility of looking for low contrast weak structure. With the probe's orbit passing over the pole, the structure of the polar field can be directly measured. The detector plane of the system receives a telecentric image of the objective. Because there is an aperture in this focal plane that can both move and change size, polarized line profiles can be obtained at arbitrary points with variable spatial resolution. The telescope microprocessor searches for the magnetic elements and then constructs the vector field.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 155-158
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  • 42
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    New perspectives for solar observations (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The merits and demerits of an approach to the Sun (more closely than about one AU) are examined. High resolution imaging (approximately 0.1 arc sec) to be obtained with the shuttle-borne solar optical telescope, will permit conclusive observations relating to the structure of the quiet solar atmosphere, sunspots, spicules, oscillations, and many other problems of solar astrophysics. Beyond this limit important unresolved structure will exist, especially in optically thin regions or in regions with strong magnetic fields. Ambiguity will remain in solar imagery because a single line of sight cannot suffice completely to untangle the vertical dimension from the two horizontal dimensions. A solar probe with a complement of solar telescopes would provide two lines of sight for solar viewing and increase knowledge of the three dimensional structure of the solar atmosphere.
    Keywords: SOLAR PHYSICS
    Type: JPL A Close-up of the Sun; p 81-88
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  • 43
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    Gravitational experiments on solar probe (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: A covariance analysis was performed for a solar probe trajectory which encounters the sun at four solar radii. The unknown parameters in the analysis are the six initial cartesian coordinates for the probe, six initial cartesian coordinates for the earth, the astronomical unit, the solar gravitational quadrupole coefficient and two post Newtonian meters (beta, gamma). Errors in the unknown parameters were computed as a function of standard errors on the radio tracking data and on the nongravitational forces which act on the probe. Results were obtained for several tracking geometries and for several orbital inclinations to the ecliptic. The analysis shows that the principal scientific result from the radio tracking of a solar probe would be the determination of the quadrupole moment, which would place a constraint on models of the solar interior.
    Keywords: SOLAR PHYSICS
    Type: A Close-up of the Sun; p 42-57
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  • 44
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    Ground tracking system phase fluctuation spectra (1978)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Spectral analysis of solar wind plasma fluctuation requires knowledge of the average ground tracking system phase fluctuation spectrum. Typical ground tracking system phase fluctuation spectra are presented as deduced from two-way S-band Doppler noise measured at large Sun-Earth-Probe angles.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 125-128
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  • 45
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    A solar wind turbulence event during the Voyager 1978 solar conjunction profiled via new DSN radio science (1978)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A radio science data capability within the DSN Tracking System is described. This capability consists of routine provision of phase fluctuation data concurrently computed over several different time scales. This capability was used to observe phase fluctuation spectral characteristics during a rapid increase in solar wind turbulence that occurred during a July 23, 1978 track of the Voyager 1 spacecraft by Deep Space Station 11. It is suggested that the capability will prove useful in studies of variations of solar wind phase fluctuation spectral characteristics with, for instance, parameters such as the solar cycle and radial distance.
    Keywords: SOLAR PHYSICS
    Type: The Deep Space Network; p 55-58
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  • 46
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    The case for a burst from 3U 0614+09 (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A single flare event with a rise time of about 7 s and a decay time of approximately 40 s was observed by the Goddard cosmic X-ray spectroscopy experiment on OSO-8 during observations of 3U 0614+09 in September 1975. The possibility is discussed that the source was 3U 0614+09, which has been compared with the low-mass binary Sco X-1. The spectra during the event could be fitted with blackbody (kT = 0.8-1.1 keV) or thermal bremsstrahlung (kT = 1.1-2.5 keV) models with absorption by cool material. In the blackbody model the source was of the order of 1 million cm in size.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 182
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    Formation of a rotational accretion column (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: We consider the problem of the flow produced by the accretion of gas from a rotating cloud onto a point gravitational source. It is shown that, for a cloud initially in uniform rotation, the effect of accretion is to produce a Taylor column in the cloud parallel to the rotation axis. Only gas within the column is accreted; the gas outside the column undergoes oscillatory flow, which is probably subject to shear instability. The column forms in approximately one-half rotation period from the time at which accretion begins. Its initial radius is determined by the accretion rate and the angular velocity of the cloud. Application of the results to the formation of Jupiter by accretion is discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 219
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    An experimental investigation of the condensation of silicate grains (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Results are presented for a series of laboratory experiments designed to investigate the nucleation of small silicate grains from a vapor of astrophysically significant elements and compounds. In the experiments, magnesium silicate grains were condensed by simultaneously evaporating Mg and SiO solids into an atmosphere of argon or hydrogen at a pressure of a few torr. The results show that at low temperatures (up to a few hundred degrees C) the condensates are amorphous grains and have widely varying stoichiometries. The thermodynamically most stable compounds (Mg2SiO4, MgSiO3, SiO2) do not form readily, but all initial condensates can be converted to crystalline forsterite (Mg2SiO4) by heating to 1000 C in vacuum. At higher temperatures (above 700 K) it becomes more difficult to nucleate any silicates, and those that do form are amorphous, indicating that surface energies and kinetic effects are very important in determining under what conditions condensation will occur. The IR spectra of the experimentally produced magnesium silicates are found to have a strong resemblance to those observed in many astronomical clouds.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 222
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    Soft X-ray emission from a newly discovered supernova remnant in Cygnus (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 222
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    Gamma ray spectroscopy in astrophysics: An observational overview (50 keV-20 MeV) (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The observational status of gamma ray astronomy based on results reported prior to April 1978 is discussed. Specific line observations are reviewed from the Sun, the galactic plane, the Galactic Center region, the active Galaxy NGC 5128 (Cen A), the Crab Nebula region, and a transient source in the general direction of the anti-Galactic Center region. A statistical method is described which determines the relative probability that a given, reported observation is due to an external source as compared to a random fluctuation in the experimental background counting rate. Only a few of the many reported observations can be considered likely extraterrestrial observations of an extraterrestrial source made with a confidence level of 99%.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center Gamma Ray Spectry. in Astrophys.; p 42-68
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    A hard X-ray and gamma ray observation of the 22 November 1977 solar flare (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Franco-Soviet experiment package Signe 2 MP for solar and cosmic X and gamma ray observations, launched aboard a Soviet Prognoz satellite into a highly eccentric earth orbit is described. An uncollimated NaI detector 37 mm thick by 90 mm diameter, placed on the upper surface of the satellite faced the sun. A collimated lateral NaI detector 14 mm thick by 38 mm diameter also faced the sun, and a similar lateral detector faced the anti-solar direction. Data tapes reveal an intense solar flare up to energies of up to 5 MeV, with evidence for line emission at 2.23 MeV and possibly 4.4 MeV. The event observed was associated with the Mc Math Plage Region 15031, and an H-alpha flare of importance 2B. It is not yet clear what radio emission is associated with the X-ray observation.
    Keywords: SOLAR PHYSICS
    Type: NASA. Goddard Space Flight Center Gamma Ray Spectry. in Astrophys.; p 70-75
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    Gamma-ray lines - A new window to the Universe (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Gamma-ray emission is considered in terms of its usefulness in determining the physics of nucleosynthesis, the interstellar medium, solar flares, supernovae, and neutron stars. The mechanism of gamma-ray line emission is reviewed, i.e., nuclear deexcitation, radiative capture, positron annihilation, and possibly cyclotron radiation in the strong magnetic fields of neutron stars. Various gamma-ray spectra, obtained from balloon and satellite data, are analyzed with attention to solar particle energies and densities, including particle emission from black-hole supernova remnants.
    Keywords: ASTROPHYSICS
    Type: Physics Today; 31; Mar. 197
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    New observations of ultraviolet variability in Wolf-Rayet stars (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Observations of ultraviolet variability in Wolf-Rayet stars have been made with the ANS satellite Ultraviolet Photometer Experiment. Significant variations are detected in several of the observed stars, the timescale of the variability ranging from a few minutes to several months.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 183
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    The nature of Aquila X-1 (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Photometry in the UBV spectra was used to observe Aquila X-1. This X-ray source, usually producing flux on the order of 1-10% that of the Crab Nebula, often behaves in a manner resembling the behavior of galactic X-ray stars. A description of the calibration methods used in the observations is presented, with attention to photoelectric-photographic methods. These observations suggest a quiescent spectral class near Ko, i.e., a dwarf at a distance of 1.6 kpc. The more intense X-ray emissions are said to be generated from internal heating of the stellar atmosphere, with additional energy supplied by a low-mass companion star. This explaination is at variance with the semi-detached Roche model.
    Keywords: ASTROPHYSICS
    Type: Nature; 271; Feb. 16
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    Evidence that cosmic gamma-ray bursts are galactic (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Balloon observations registering scatter angles in a liquid scintillator have revealed gamma-ray bursts having energies as low as 10 to the -7th ergs per square cm. The burst distribution is graphed according to energy and frequency. The hypothesis that the bursts are galactic in origin is in good agreement with their small recorded energies and their predicted distribution on the graph.
    Keywords: ASTROPHYSICS
    Type: Nature; 271; Feb. 16
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    Distance limit for a class of model gamma-ray burst sources (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: It is pointed out that MeV photons have actually been observed in bursts. These observations imply that the nonrelativistic sources cannot be further away than a few kpc from the sun and, therefore, must be galactic. The 27 April 1972 event observed by Apollo 16 shows at higher energies a power law spectrum with a possible line feature around 4 MeV. The optical depth of a homogeneous, isotropic radiation field is estimated with the aid of formulae used by Nikishov (1962) and Jauch and Rohrlich (1955). On the basis of an investigation of the various factors involved, it is tentatively suggested that the gamma-ray bursts which have been detected are galactic, but are in the majority of the cases not connected with unique irreversible star transformation. It appears also unlikely that the gamma-ray bursts are connected with galactic novae.
    Keywords: ASTROPHYSICS
    Type: Nature; 271; Feb. 9
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    Supernovae and the formation of the solar system (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The evidence that a supernova explosion may have triggered the formation of the solar system is reviewed. It cannot be said on the basis of the investigation that the supernova trigger is absolutely necessary for planetary system formation. However, it does appear according to the isotopic evidence that a supernova did blow up within a few million years of the solidification of objects in the solar system. If such an event occurred, it is reasonable to assume that the resultant supernova shock had a causal connection with the formation of the solar system and that a supernova may be one stimulus for formation of low-mass stars.
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    Star formation in molecular clouds (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A general overview is presented of the findings of molecular line and infrared astronomy regarding star formation. Beginning with the statement that stars, and therefore, planets, form from molecular clouds, it is argued that the growing body of data on conditions in molecular clouds should serve as input parameters for theoretical calculations of star and planet formation. The fact that the gravitational potential energy of molecular clouds far exceeds their thermal energy implies that the required rate of star formation is easily explained. Indeed the most important problem in this field is that the rate of star formation predicted from molecular cloud studies is too high. Until this problem is understood, additional modes of inducing star formation, while they may be occurring, only add to the existing difficulties.
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    The cloudy state of interstellar matter (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The expression 'cloudy state' is used to describe the state of the diffuse interstellar matter, with emphasis on its denser and more opaque regions. Questions of morphology with respect to the Galaxy are examined, taking into account neutral hydrogen, molecular regions, H II regions, infrared sources and masers, coronal gas in the Galaxy, and the major components of the interstellar medium. Aspects of dynamics are also considered, giving attention to the two-phase interstellar medium, the three-phase interstellar medium, the density-wave compression of clouds, and problems related to the concept of collapsing clouds. Developments concerning chemistry are explored. Radioactive chronologies are discussed along with isotopic anomalies and aspects of interstellar chemistry.
    Keywords: ASTROPHYSICS
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    Some implications for interstellar molecules of a low electron abundance in dense clouds (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 83; Dec. 197
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    Discovery and optical identification of 2S0921-630 (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The discovery of a faint X-ray source at approximately 282 deg galactic longitude, -9 deg galactic latitude with the rotation modulation collimator X-ray detectors aboard SAS 3 is reported. The source is designated 2S 0921-630 and is tentatively identified, on the basis of an optical search, with a 17th magnitude star exhibiting the He II line at 4686 A and H-beta in emission. The optical spectrum of this star is shown to be similar to those of the optical counterparts of Sco X-1 and other such galactic X-ray sources. It is suggested that 2S 0921-630 may belong to the class of low-luminosity galactic X-ray binaries.
    Keywords: ASTROPHYSICS
    Type: Nature; 276; Dec
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    Hard X-rays from U Geminorum (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The A-2 experiment on HEAO 1 has discovered that the dwarf nova U Geminorum can be a weak source of hard X-rays at optical maximum. During the outburst in October 1977, when a strong soft X-ray flux was discovered, a 2-10-keV flux was also observed. Evidence is presented that this flux appeared with the rise to optical maximum, about half a day before the soft X-rays appeared, and persisted about 2 days. During these first 2 days of the outburst the average flux was 2.4 x 10 to the -11th erg/sq cm per sec, corresponding to a luminosity of 2.8 x 10 to the 31st erg/s for a distance of 100 pc and an absorbed thin thermal spectrum with kT of about 5 keV. During optical minimum an OSO 8 upper limit implies a luminosity less than 10 to the 31st erg/s. Restrictions on models of U Geminorum are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 226
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    Ice mantles and abnormal extinction in the Rho Ophiuchi cloud (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 226
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  • 64
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    Measurements of extreme-ultraviolet emission-line profiles near the solar limb (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Line profiles of optically thin extreme-ultraviolet emission lines observed in a quiet sun region at positions within and above the white-light limb with the NRL slit spectrograph (S082-B) on Skylab are discussed. Absolute line intensities and full widths at half-maximum are presented for lines formed over the temperature range from about 10,000 to 22,000 K. The line intensities are compared with the predictions of simple atmospheric models consisting of a spicule component and a thin spherically symmetric or network models, but can be explained by assuming that the emission arises from spicule-like inhomogeneities. Random mass-motion velocities are calculated. The velocity increases with increasing temperature of line formation. Near the limb and above about 4000 K the calculated velocity is consistent with the predictions of a constant acoustic flux passing through the transition zone. For the ions formed at temperatures not less than about 63,000 K, the velocity is found to increase with increasing height above the white-light limb.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 226
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  • 65
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    Resonant absorption of Alfvenic surface waves and the heating of solar coronal loops (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A first-order mass- and energy-balance model is developed for steady-state EUV 'coronal rain' loops that are not associated with postflare events and are often seen over sunspot umbrae. The model disregards variations in a loop's thermodynamic and magnetic properties along magnetic-field lines and yields average properties of the resonant absorption sheath, the boundary layer, and the loop's interior. Both irreversible heating by Alfvenic surface waves and energy transport via induced boundary-layer convection are taken into account in the analysis. Results that include predictions of the temperatures of the sheath and the boundary-layer plasma, the temperature of the interior plasma, the radiative output of the loop, and the filling factor associated with this radiation are given in terms of the period and velocity amplitude of the relevant surface wave as well as various parameters that characterize a typical 'coronal rain' loop. These results are shown to be consistent with the observed minimum and maximum temperatures as well as the radiative output of typical 'coronal rain' loops.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 226
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  • 66
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    Gamma-ray astrophysics - A new look at the universe (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Gamma-ray astronomy, which may be defined to include the spectral region from above 100 keV to about 1000 GeV, permits investigation of the most energetic photons originating in the Galaxy and beyond. These observations provide the most direct means of studying the largest transfers of energy occurring in astrophysical processes, including the dynamic effects of the energetic charged cosmic-ray particles, element synthesis, and particle acceleration. Further, gamma-rays suffer negligible absorption or scattering as they travel in straight paths. Hence they may survive billions of years. Studies of the spatial, temporal, and energy distribution of cosmic gamma-rays will, therefore, provide fundamental new information for resolving some of the major problems in astrophysics today. Attention is given to the gamma-ray observations of the solar system, stellar objects, diffuse gamma-ray emission from the Galaxy, other galaxies and cosmology, and future prospects.
    Keywords: ASTROPHYSICS
    Type: Science; 202; Dec. 1
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  • 67
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    Methane detected in Orion A (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: This letter reports the detection of line emission from the Orion Molecular Cloud corresponding to six distinct pure-rotational delta J = 0 transitions in CH4. The transitions observed and the transition frequencies are: J = 11 E(2) - E(1), 4600.359 MHz; J = 18 F1(4) - F2(1), 76,231.45 MHz; J = 18 A1(2) - A2(1), 76,700.02 MHz; J = 19 F1(4) - F2(1), 75,944.99 MHz; J = 19 F2(4) - F1(1), 78,233.59 MHz; and J = 20 F2(5) - F1(2), 82,873.59 MHz. The observed spectra at the six transition frequencies are plotted, and all but two of the methane lines are found to be very narrow (about 2 km/s). It is noted that the small velocity widths of the four weaker lines and an observed variability of the J = 18 A line are classic characteristics of a maser and that the excitation appears to be nonthermal. An effective excitation temperature of 1100 to 2100 K is estimated for the methane in Orion A.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 226
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  • 68
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    Predicted color excess ratios versus interstellar grain size (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Various color excess ratios, the ratio (R) of total to selective extinction, and values of the wavelength of maximum interstellar linear polarization (lambda max) are computed and displayed as functions of mean interstellar grain size and absorption coefficients. E(V-K)/E(B-V)-E(u-b)/E(b-y) is shown to be highly sensitive to changes of mean grain size. The shape of the R versus lambda max curve is shown to depend on the amount of absorption initially present in the grains, and on the absorptivity of the material added to the grains. While no simple model of grain growth has been found to fit all the observations, the two stars with the largest values of lambda max (HD 147889 and W67) support the concept of dielectric mantles growing on dielectric grains. It is further shown that more accurate uby and JKL photometry of heavily reddened stars would permit better discrimination between grain growth theories.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 225
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  • 69
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    Interaction between emission-line filaments and highly energetic explosions in QSOs (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The conditions under which QSO line-emitting regions can survive a relativistic explosion are investigated along with the question of whether past and future observations can place constraints on both predicted highly energetic outbursts of ultrarelativistic plasma or LF electromagnetic radiation and the line-emitting gas. Observed properties of QSO emission-line regions are reviewed, and the interaction between a relativistic explosion and a dense cloud is analyzed for the cases of a sudden release of relativistic plasma and an outburst of LF electromagnetic waves. Bremsstrahlung X-ray emission from shocked QSO filaments is calculated, the evolution of dense QSO clouds is examined, and radiative acceleration is excluded as the process responsible for the high bulk velocities of filaments, at least in sources that display energetic outbursts. An alternative mechanism involving highly energetic explosions is proposed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 225
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  • 70
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    Gas flow in the barred spiral galaxy NGC 5383 (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Line-of-sight gas velocities calculated from a numerical hydrodynamical model of a barred spiral galaxy are compared with the observations and models made by Peterson, Rubin, Ford, and Thonnard of the gas flow in NGC 5383. The hydrodynamical model provides a somewhat better fit to the observations of NGC 5383 than does their symmetric, warped-disk model. It is argued that the basic model appropriate to understanding the gas motions in barred spiral galaxies is not circular rotation but rather a characteristic elliptical pattern of flow.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 225
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  • 71
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    The formation of molecules in interstellar clouds from singly and multiply ionized atoms (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The suggestion is considered that multiply ionized atoms produced by K- and L-shell X-ray ionization and cosmic-ray ionization can undergo ion-molecule reactions and also initiate molecule production. The role of X-rays in molecule production in general is discussed, and the contribution to molecule production of the C(+) radiative association with hydrogen is examined. Such gas-phase reactions of singly and multiply ionized atoms are used to calculate molecular abundances of carbon-, nitrogen-, and oxygen-bearing species. The column densities of the molecules are evaluated on the basis of a modified version of previously developed isobaric cloud models. It is found that reactions of multiply ionized carbon with H2 can contribute a significant fraction of the observed CH in diffuse interstellar clouds in the presence of diffuse X-ray structures or discrete X-ray sources and that substantial amounts of CH(+) can be produced under certain conditions.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 225
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  • 72
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    On the origin of Hawking mini black-holes and the cold early universe (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A simple argument is outlined leading to the result that the mass of mini black holes exploding today is 10 to the 15th power g. A mathematical model is discussed which indicates that the equation of state is greatly softened in the high-density regime and a phase transition may exist, such that any length (particularly very small sizes) will grow with time irrespective of its relation to the size of the particle horizon. It is shown that the effect of spin-2 mesons with respect to the equation of state is to soften the pressure and make it negative. An analytical expression is given for the probability that any particular region in a hot early universe will evolve into a black hole.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 184
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  • 73
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    EUV spectra from Skylab /1175-1940 A/ - Mass motions in the transition zone in regions of solar activity (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The profiles of spectral lines in the 1100-2000-A range emitted by transition-zone ions in regions of solar activity are discussed. The data were recorded by the NRL spectrograph on Skylab. At the spatial resolution of the Skylab spectrograph (2 x 60 arcsec), it is shown that the line profiles result from the superposed emission of a number of physically distinct regions at different electron densities and with different mass motions. Although high densities are found for some surgelike phenomena at transition-zone temperatures, the densities can also be comparable to normal active-region densities. Line profiles, as well as spectral line intensities, must be considered if meaningful theoretical models of dynamic activity in the transition zone are to be constructed.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 69; 1, Se; Sept
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  • 74
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    The 3 K blackbody radiation, Dirac's Large Numbers Hypothesis, and scale-covariant cosmology (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A program is described which is intended to derive a generalized system of gravitational equations that allow (but do not require) G to vary, to use the 3-K blackbody radiation to fix the relation between G and the gauge function, and to employ Dirac's (1937) Large Numbers Hypothesis to derive the geometry of the universe. Einstein's equations are retained in their total integrity, but the specification is made that they are valid only when gravitational units are used. A scale-invariant form of Einstein's equations is obtained, and from this are derived the energy conservation law, the baryon-number conservation law, and the appropriate cosmological equations. Dirac's proposals of 1937 and 1973 are incorporated into the formalism, and a gauge based on consolidation of the 3-K blackbody radiation is presented. A unique solution for the geometry of the universe is determined for zero curvature solely from the 3-K radiation and the Large Numbers Hypothesis; this solution predicts a deceleration parameter exactly equal to unity.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 224
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  • 75
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    The composition of corotating energetic particle streams (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The relative abundances of 1.5-23 MeV per nucleon ions in corotating nucleon streams are compared with ion abundances in particle events associated with solar flares and with solar and solar wind abundances. He/O and C/O ratios are found to be a factor of the order 2-3 greater in corotating streams than in flare-associated events. The distribution of H/He ratios in corotating streams is found to be much narrower and of lower average value than in flare-associated events. H/He in corotating energetic particle streams compares favorably in both lack of variability and numerical value with H/He in high-speed solar wind plasma streams. The lack of variability suggests that the source population for the corotating energetic particles is the solar wind, a suggestion consistent with acceleration of the corotating particles in interplanetary space.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 224
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  • 76
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    Impulsive solar X-ray bursts (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A set of 22 simple impulsive solar flares, identified in the OSO 5 hard X-ray data, has been analyzed together with coincident microwave and meter-wave radio observations. The rise times and fall times of the X-ray bursts are found to be highly correlated and effectively equal, strongly suggesting a flare-energizing mechanism that is reversible. The good time resolution available for these observations reveals that the microwave emission is influenced by an additional process, evident in the tendency of the microwave emission to peak later and decay more slowly than the symmetric X-ray bursts. Meter-wave emission is observed in coincidence with five events which also show strong time correlation between the X-ray and microwave burst structure. This meter-wave emission is characterized by U-burst radiation, indicating confinement of the flare source. The relationship found between the X-ray burst duration and the calculated flare diameter, together with the thermal character of the X-ray spectra, gives additional support to the hypothesis that the impulsive component is driven by adiabatic compression and expansion of a magnetically confined plasma which is the common primary source of both X-ray and microwave emission.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 223
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  • 77
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    Physics of the primitive solar nebula and of giant gaseous protoplanets (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: It has been proposed that the supernova responsible for injecting Al-26 into the early solar system was in fact responsible for triggering the collapse of an interstellar cloud in order to produce a system of stars, one of which would be the solar system. Details concerning the mechanism involved in such a process are discussed. Attention is given to the evolution of the primitive solar nebula, the instabilities in the primitive solar nebula, and the giant gaseous protoplanets. The principal conclusion to be drawn from the material presented is that the primitive solar nebula was a rather chaotic place, highly turbulent, with the multiple formation of giant gaseous protoplanets.
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  • 78
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    Fragmentation of molecular clouds (1978)
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    Publication Date: 2011-08-17
    Description: Fragmentation is generally considered to be the initial process that a molecular cloud must undergo before stars can form. Yet its role in determining the final mass spectrum remains obscure. It appears that gravitational fragmentation, considered as a unique process, is unsatisfactory. Both fragmentation and complementary physical processes are, therefore, discussed. One of the principle aims of the discussion is to indicate how stars of solar mass (and more generally, how the initial mass spectrum of stars) can form. Attention is given to the evidence for fragmentation, opacity-limited fragmentation, magnetic flux-limited fragmentation, fragmentation induced by molecule formation and excitation, protostellar heat input, fragment coalescence, accretion, binary formation, and probabilistic theories.
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  • 79
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    Numerical calculations of protostellar hydrodynamic collapse (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Although 1-D (spherically symmetric) experiments of protostar collapse are highly idealized, they are the only ones which have been carried to a stage where a 'stellar' object is formed. Experiments have shown that the parameters (e.g., radius and luminosity) of the visible stellar core are sensitive to the assumed initial conditions, particularly the initial density. One of the major findings of 2-D numerical experiments is the formation of rings. Three-dimensional hydrodynamical calculations indicate that a collapsing cloud will break up into two or more orbiting subcondensations with the possible subsequent development of a stellar multiple system.
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  • 80
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    Condensation processes and the formation of cosmic grains (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The case of condensation from a gas in the absence of any preexisting grains or nuclei upon which condensation can occur is considered. Some of the analysis is expected to apply to condensation on grains already present. An attempt is made to examine the basic assumptions of the various procedures used to describe condensation and to examine their applicability to astronomical systems. Attention is given to thermodynamic equilibration calculations, nucleation theory, kinetic mechanisms, the theoretical mechanisms, and condensation experiments.
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  • 81
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    Densities in the quiet sun and polar coronal holes from EUV line ratios involving O III /1666.15 A/ (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 226
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  • 82
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    The observational status of the Beta Cephei stars (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Beta Cephei stars are a group of variables of spectral type B, whose light and radial velocity periods lie between about three and seven hours. An up-to-date summary of the observational data for individual stars considered to be members of the Beta Cephei group is provided. The general properties of Beta Cephei stars as determined from a comparison between theory and observation are considered, taking into account location in the HR diagram and evolutionary state, physical properties, statistics and galactic distribution, and period-luminosity relation and pulsation mode. Recent trends concerning the observation of Beta Cephei stars are examined, giving attention to a search for new variables, ultraviolet observations from spacecraft, and high-resolution studies of profile variations.
    Keywords: ASTROPHYSICS
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  • 83
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    The central, compact source in the Cygnus A galaxy (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Single, optically thin, component models as well as double, optically thick at low frequencies, component models have been examined in trying to explain the central source in the nucleus of Cygnus A. In the course of exploring those models, it is found that this compact radio source may be quite similar to other compact and variable sources in Seyfert galaxies and quasars. Double component models generally do better because they fit the X-rays, and there is a good chance that the X-rays arise in the central source; these models can naturally explain variability which may already have been detected in X-rays. The IR is most likely due to emission by cold dust in the nucleus of Cygnus A. Optical emission is, very likely, primarily thermal, except perhaps at UV wavelengths. A number of observations are suggested to check the predictions of this work.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 225
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  • 84
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    Sources of magnetic fields in recurrent interplanetary streams (1978)
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    Publication Date: 2011-08-17
    Description: The paper examines sources of magnetic fields in recurrent streams observed by the Imp 8 and Heos spacecraft at 1 AU and by Mariner 10 en route to Mercury between October 31, 1973 and February 9, 1974, during Carrington rotations 1607-1610. Although most fields and plasmas at 1 AU were related to coronal holes and the magnetic field lines were open in those holes, some of the magnetic fields and plasmas at 1 AU were related to open field line regions on the sun which were not associated with known coronal holes, indicating that open field lines may be more basic than coronal holes as sources of the solar wind. Magnetic field intensities in five equatorial coronal holes, certain photospheric magnetic fields, and the coronal footprints of the sector boundaries on the source surface are characterized.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 83; Sept. 1
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  • 85
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    Optical detection of local interstellar particles during an out-of-ecliptic mission (1978)
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    Publication Date: 2011-08-17
    Description: A proposed NASA/ESA 'out of ecliptic' mission for placing limits on the brightness of the interstellar (IS) relative to the interplanetary (IP) component of zodiacal light is discussed. The brightness integral used to estimate the monochromatic is introduced, and it is explained that, although the interstellar contribution is below the limit of detectability for earth-based measurements, sunwards viewing from a spacecraft located at a distance of 1 AU would be able to detect the IS component. The color difference between the IS and IP components is considered in an analysis of the upper limit of IS component detectability.
    Keywords: ASTROPHYSICS
    Type: Nature; 275; Sept. 7
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  • 86
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    Relativistic blast-wave model for the rapid flux variations of AO 0235+164 and other compact radio sources (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A relativistic blast-wave version of a signal-screen model is developed which can adequately explain the details of the flux-density and structural variations of compact extragalactic radio sources. The relativistic motion implied by flux variations is analyzed with respect to the synchrotron spectrum of the BL Lac object AO 0235+164 observed during outbursts, and a signal-screen model for rapidly expanding shells produced by ultrarelativistic blast waves is examined. The approximate observed structure of the blast wave at three stages in its evolution is illustrated, each stage is described, and the model is applied to the flux density outburst in AO 0235+164 observed in late 1975. The results show that a relativistic blast-wave model can in general reproduce the main features of the observed flux variations in compact sources. Some problems with the proposed model are briefly discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 224
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  • 87
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    The infrared source associated with Sh 2-149 (1978)
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    Publication Date: 2011-08-17
    Description: Observations at optical and infrared wavelengths of the bright infrared point source in the direction of Sh 2-149 are used to determine a spectral type (M1) and luminosity class (Ib-II) for the object. These observations contradict the suggestion of Bergeat et al. (1975) that the object is a highly reddened O star. The estimated visual extinction (approximately 5-7 magnitudes) and luminosity class derived from the present observations are used to estimate the distance (about 1-3 kpc) to the infrared source.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 67; 2, Ju; July 197
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  • 88
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    Limb-brightening observations from the OSO-7 satellite. III - Comparison of EUV line intensities of Fe XII, Fe XI, Fe XV, Si X and S XII, Si IX and S XI with predictions (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Continuing a study of heliocentric dependence of EUV emission line intensities observed by the Goddard OSO-7 spectroheliograph in 1972, the variation of lines of the ions Fe XII, Fe XI, Fe XV, Si X and S XII, Si IX and S XI is compared with the results of individual calculations for these ions, including theoretical intensities presented for Fe XII and Fe XI. Agreement is found to be good for Fe XII and reasonable for some of the lines of the other ions which in general are weaker in intensity. Several apparent anomalies are found however which may be due to unknown line components near the wavelengths observed.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 67; 1, Ju; June 197
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  • 89
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    Ionization of interstellar H2 clouds by supernovae (1978)
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    Publication Date: 2011-08-17
    Description: Two destruction mechanisms for molecular hydrogen in the H I regions of the interstellar medium were given by Stecher and Williams (1967). The first is dominant in weak radiation fields and involves photon excitation (at about 1000 A) to the first excited electronic state with a subsequent decay into the vibrational continuum of the ground state. The second destruction mechanism is dominant in the strong photon fields that exist when a supernova explosion occurs. It involves photoionization (at about 1000 A) from metastable high vibrational levels produced by photon excitation (in the same wavelength range) to an excited electronic state and subsequent decay to bound vibrational levels. It is shown that ionization of molecular hydrogen can occur at considerable distances from such supernova events while the atomic hydrogen remains neutral. The effect should be observable in the dispersion measures of new pulsars.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 67; 1, Ju; June 197
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  • 90
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    Interplanetary gas. XXII - Plasma tail disconnection events in comets - Evidence for magnetic field line reconnection at interplanetary sector boundaries (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Attention is focused on a form of cometary activity which has been known for some time but is poorly understood: the discarding of a plasma tail by a comet. A link is found between plasma-tail rejections and conditions in the solar wind. A model is presented in which a disconnected tail is the end result of magnetic-field-line reconnection in the cometary ionosphere caused by the traversal of a magnetic sector boundary. Observations of plasma tails appear to be the best and only method at present of mapping the interplanetary sector structure out of the ecliptic plane.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 223
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  • 91
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    An instability of finite amplitude circularly polarized Alfven waves (1978)
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    Publication Date: 2011-08-17
    Description: A demonstration is presented that a finite-amplitude circularly-polarized Alfven wave is generally unstable in a MHD fluid. The wave decays by a four-wave coupling process in which the daughter waves are forward propagating random density and magnetic fluctuations and a backward-propagating magnetic wave. For parameters typical of the solar corona and the solar wind (thermal to magnetic energy density ratios between 0.1 and 1, and values between 0.1 and 0.9 for the ratio of magnetic energy density of the initial Alfven wave to that of the background magnetic field), large decay rates are found.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 219
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  • 92
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    Hercules X-1 = HZ Herculis - A multiperiod variable (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Fundamental rotation properties of the free modes of oscillation of a star are employed to account for the various periodicities observed in the X-ray binary system HZ Her/Her X-1. The various rotation rates may be taken as defining a set of beat periods associated with the quasiregular flareups of HZ Her. This analysis, involving only one free parameter, provides a single physical mechanism to explain five observed periods of the binary system, including periods of 1.7 days, 35 days and 10 to 12 years.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 219
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  • 93
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    The rocket-ultraviolet spectrum and models of the planetary nebula NGC 7662 (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Ultraviolet spectral analysis of NGC 7662 has revealed a Balmer line distribution indicating a C/O ratio of unity. This abundance of carbon is characteristic of mixing between the central star and the outer envelope of the planetary nebula. A continuum spectrum is observed from the star and the nebula, radiating its energy via the two photon process through neutral hydrogen. Spectral lines were fitted to apply to the predictions of three models of the nebular structure. UV observations were compared with visible, IR, and radio observations.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 219
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  • 94
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    Electron densities in solar flare and active region plasmas from a density-sensitive line ratio of Fe IX (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 219
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  • 95
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    The light curve of the nucleus of comet d'Arrest (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: This paper reports new photoelectric photometry of the nucleus of P/d'Arrest (1976e) during August 4, 5, and 6, 1976 (UT), just before perihelion passage. The comet appeared as a bright stellar nucleus with a faint surrounding coma. The average visual magnitude from the nuclear region (16-arcsec diaphragm) was 11.60. The visual brightness varies with an amplitude of 0.15 plus or minus 0.02 mag. There is evidence for a period of 5.17 plus or minus 0.01 hr. We interpret such a periodic variation as due to the rotation of the nucleus. The colors of the nuclear region are very similar to those of a solar-type star, and they do not vary significantly with aspect angle.
    Keywords: ASTROPHYSICS
    Type: Icarus; 34; Apr. 197
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  • 96
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    Superdense neutron matter (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A relativistic theory of high-density matter is presented which takes into account the short-range interaction due to the exchange of spin-2 mesons. An equation of state is derived and used to compute neutron-star properties. The prediction of the theory for the values of maximum mass and moment of inertia for a stable neutron star are 1.75 solar masses and 1.68 by 10 to the 45th power g-sq cm, in very good agreement with the presently known observational bounds. The corresponding radius is found to be 10.7 km. It is found that the inclusion of the spin-2 interaction reduces the disagreement between the relativistic and nonrelativistic theories in their predictions of masses and moments of inertia.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 221
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  • 97
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    Direct observation of the latitudinal extent of a high-speed stream in the solar wind (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The latitudinal boundaries of stationary fast solar wind streams emerging from equatorward extensions of the sun's polar coronal holes are studied. Simultaneous data from the Helios 1 and Imp spacecraft at different heliographic latitudes are compared. The measured latitudinal speed gradient of 30 km/s/deg shows that large angular speed gradients occur at the leading edges of fast streams and also with respect to latitude. The data indicate that longitudinal speed gradients are steeper near 0.3 AU than at 1.0 AU. Generally, regions with large angular speed gradients are observed to separate fast streams from the surrounding slower plasma. This suggests the existence of mechanisms which diminish longitudinal speed gradients as the plasma travels toward 1.0 AU. It also seems that the distribution of solar wind speeds on a near-sun spherical surface has large mesalike high-speed regions. Comparisons of Helios 1 and Imp data with corona observations supports the hypothesis that high-speed solar wind streams emerge from coronal holes.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 83; Mar. 1
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  • 98
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    Some problems with the interpretation of recent microwave background observations in the direction of galaxy clusters, or, beware of negative antenna temperatures (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Recently reported observations of the 3-K microwave background in the direction of rich clusters of galaxies should be viewed as placing stringent limits on the mass of cooler ionized gas within the clusters, rather than as a verification of thermal bremsstrahlung models for cluster X-ray sources. At the high radio frequencies employed in the observations, there is a positive contribution to the observed source-brightness distributions from free-free emission by any cooler gas. This can overwhelm the anticipated inverse Compton diminution of the background radiation, even when the total mass in cooler gas is significantly less than the mass of hot plasma required to explain the X-ray source. Future experiments of this type should be conducted only when atmospheric stability is sufficient to permit lengthy drift scans across the clusters. Extreme care must be taken to remove the contributions from any discrete sources.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 220
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  • 99
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    An interstellar cloud density from Copernicus observations of CO in the spectrum of Zeta Ophiuchi (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Interstellar CO absorption bands in Copernicus spectra of Zeta Oph have been studied. Absorption profiles, computed under the assumption that excitation is due to collisions with H2 molecules and interaction with the 3-K background radiation field, were fitted to the reduced data of nine bands. When a gas kinetic temperature of 56 K is assumed, the best-fit condition implies a hydrogen-nucleus density of 120 per cu cm, a CO column density of 1.2 by 10 to the 15th power per sq cm, and a radial-velocity dispersion of 0.9 km/s. The relevance of these results to existing ideas concerning the Zeta Oph interstellar clouds is discussed. It is suggested that the strongest interstellar component is not circumstellar in origin but is instead part of a supernova remnant. Simple calculations are made to establish the plausibility of the supernova-remnant identification. This suggestion is also supported by Heiles's (1976) 21-cm pictures.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 220
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  • 100
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    Heliocentric distance dependence of the interplanetary magnetic field (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Numerous spacecraft measurements bearing on the heliocentric distance dependencies of both large- and small-scale properties of the interplanetary magnetic field (IMF) are assembled and compared. These data tend to indicate that the average of the radial field component varies as the inverse square of distance. However, the azimuthal component is rather strongly a function of time, being influenced by both the time-dependent solar wind speed and the evolution of the source field at the sun. Thus, unless the solar wind speed dependence is taken into account, individual sets of measurements by a single spacecraft give an azimuthal component gradient which is steeper than the inverse distance dependence predicted from the Parker spiral model. A least squares fit to the composite (five spacecraft) solar rotation average data set gives a result close to the inverse distance dependence. Preliminary Helios results suggest general consistency with the spiral model.
    Keywords: ASTROPHYSICS
    Type: Reviews of Geophysics and Space Physics; 16; Feb. 197
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