bluuebunny/crossref_metadata_2025 huggingface dataset:
A Two-Level Solar Dynamo Based on Solar Activity, Convection, and Differential Rotation
Authors: Bratenahl A. , Baum P. J. , Adams W. M.
Published: July 2016

In orthodox dynamo theory (Stix, 1976), the two basic processes, generation of toroidal from poloidal field and conversion of toroidal into reversed poloidal field, are both located in the high β regime convection zone. Generation requires that regime, since its function demands it be driven by mechanical forces. But the function and therefore the operating requirements of conversion are entirely different, and there seems to be no à priori reason, other than historical tradition coupled with failure to recognize those differences, for the assumption that conversion must also operate there. Conversion transforms the topological structure of generated flux by altering the field line connectivity, so that the principal task performed is reconnection. Reconnection is a spontaneous process which must compress and accelerate plasma if any is present. Obviously it must perform much more work in the high β convection zone than in the low β solar atmosphere. It seems natural, therefore, to expect the reconnection aspect of conversion to be located there, where the least work needs to be performed. To transfer the generated flux there, we may add to conversion another spontaneous process: eruption of bipolar structure (Parker, 1955). To transfer the reconnected flux back down, we add to generation another mechanically driven process called topological pumping (Drobyshevski and Yuferev, 1974). Topological pumping depends on the diamagnetic effect of eddy-motion (Wiess, 1966), the kind possessed by supergranulation: 3-dimensional arrangement of isolated rising plumes, surrounded by a continuous network of descending sheet-like flow. In the two-level dynamo presented here, conversion may be observed directly, since we expect it to express itself in terms of all forms of solar activity: sunspots, flares, faculae, filaments, coronal structures including coronal holes, etc., and their organization and evolution in a “solar meteorology”. It is clearly important to investigate a model that thus unites the two disciplines of solar activity and dynamo theory. Each strengthens the other and brings a greater unity to solar physics.
Location of Compact Microwave Sources with Respect to Concentrations of Magnetic Field in Active Solar Regions
Authors: Gaizauskas V. , Tapping K. F.
Published: July 2016

The slowly varying (S-) component of solar microwave emission originates in the vicinity of sunspots and chromospheric plages. A significant portion of this component is produced by bright, compact sources which are much smaller than the active regions in which they occur (Lang, 1974; Kundu et al., 1977; Donati Falchi et al., 1978; Lang and Willson, 1979). The combined radio-optical investigation reported here was initiated to explore, in regions at various stages of evolution, both the variability of compact microwave sources and their association with specific optical features.
Radio Observations of Coronal Holes
Authors: Sheridan K. V. , Dulk G. A.
Published: July 2016

Coronal holes have been observed on several occasions with the 80 and 160 MHz radioheliograph at Culgoora. At 160 MHz the holes invariably appear as areas of low brightness, either on the disk or at the limb. At 80 MHz holes on the limb always appear less bright than their surroundings but on the disk they frequently appear brighter.

The simplest interpretation is that the coronal temperature in holes near the 80 MHz critical density (8 × 107 cm−3) is higher than in normal quiet regions, but that the density at this level is lower.
On the Possibility of Identifying Coronal Holes on Synoptic Maps of the Green Corona
Authors: Letfus V. , Kulčár L. , SýKora J.
Published: July 2016

The coronal holes of the Skylab period are treated to identify them with the low-brightness regions in our synoptic maps of the λ 530.3 nm emission corona. Possibilities and difficulties of this identification are discussed.
The Coronal Responses to the Large-Scale and Long-Term Phenomena of the Lower Layers of the Sun
Authors: Sýkora J.
Published: July 2016

Based on the assumption, generally accepted over the past decade, that all the forms of solar and interplanetary activity are responses to the magnetic fields generated initially in the subphotosphere, some characteristics of the large-scale and long-term behaviour of the solar corona during the last three solar cycles are presented.
Stellar Mass Flux and Coronal Heating by Shock Waves
Authors: Couturier P. , Mangeney A. , Souffrin P.
Published: July 2016

The heating of the solar corona and the solar wind phenomenon are basically related, however, the two parts are generally modelised independently: the models of the transition zone and corona are restricted to levels lower than the temperature maximum and the solar wind models begin above it. Here we study a self-consistent oversimplified model which maintains the global balance of energy sources and sinks from the chromospheric level to the interplanetary medium. The heating mechanism chosen is the shock wave dissipation; it was shown by Gonczi et al (1977) that overlapping shock waves could carry a significant mechanical energy flux towards a static corona; here we apply the same mechanism to an expanding corona. The model includes self-consistently the different coupling between convective energy flux, conductive flux, radiative losses in optically thin atmosphere, shock wave pressure and dissipation terms. The input parameters are the base pressure, the base temperature and the mechanical flux introduced at chromospheric level in form of shock waves. If these three parameters allow a solar wind expansion, the output results are the radial variations of the density, of the temperature, of the solar wind velocity and of the mechanical flux. Due to the presence of a boundary layer associated to the steep temperature gradient in the transition zone, the three input parameters cannot be arbitrarily fixed, in fact when we impose two of them, the third one cannot vary within a large interval (i.e. within a factor of two or less), this point has been qualitatively discussed in a previous paper : Couturier et al. (1979)
On the Thermalisation of Flare-Time Energetic Electrons Observed at Radio and X-Ray Wavelengths
Authors: Degaonkar S. S. , Sawant H. S. , Bhonsle R. V.
Published: July 2016

An interesting microwave event at 2800 MHz was recorded at Ahmedabad on September 19, 1977 at 1026 UT at the same time as the H-Alpha solar flare of importance 3B. The microwave burst was of impulsive nature, with as many as twenty impulses in seventy minutes with a quasi-periodicity of 1 to 5 minutes. An X-ray burst recorded by GOES Satellite in 1-8A band showed at the same time a smooth soft X-ray profile with apparently no sign of hard X-ray bursts. This indicates that the acceleration of discrete electron streams which produced impulsive microwave bursts was not sufficient to produce the hard X-ray component but got thermalised to produce soft X-ray emission, with a gradual rise and a slow decay covering a long duration of more than 2 1/2 hours.
Flare Associated Eruptive Prominence Activity of February 1, 1979
Authors: Bhatnagar A. , Jain R. M. , Jadhav D. B. , Shelke R. N. , Bhonsle R. V.
Published: July 2016

Observations and analysis of solar flare activated ascending “Fountain type” prominence of 1 February 1979 are presented. This “Fountain” prominence rose to 180,000 km above the solar surface and gave rise to a number of ascending loops and helical structure. These “helicals” are clear manifestation of magnetic field configuration. From these observations it is shown that, as the “Fountain” prominence rises, it carries along with it the complex magnetic field which unfolds as the prominence material expands into distinct magnetic field lines. Several type III radio bursts were also seen associated with this event. No type II or IV radio emission was reported.
Decameter Radio and White Light Observations of the 21 August 1973 Coronal Transient.
Authors: Gergely T. E. , Kundu M. R.
Published: July 2016

Observations from SKYLAB have shown that coronal transients, which involve mass ejections occur quite frequently, possibly up to three times a day at solar maximum (Hildner et al., 1976). An estimated mass of ≃1015 − 1016 g (Stewart et al., 1974) and a total mechanical energy in excess of 2×1031 ergs (Webb et al., 1978) is expelled from the Sun during each event. The transients therefore play a major role in the dynamics of the outer corona and of the interplanetary medium. Joint radio and white light observations provide the best opportunity to derive the physical parameters, such as the electron density and magnetic field in different parts of the transients, and consequently to estimate the forces driving the ejecta.
Estimation of Shock Thickness from Dynamic Spectra of Type II Bursts
Authors: Sawant H. S. , Degaonkar S. S. , Alurkar S. K. , Bhonsle R. V.
Published: July 2016

Twenty type II solar radio bursts were observed during the period 1968 to 1972 by a solar radio spectroscope (240-40 MHz) at Ahmadebad. Intensity variations in type II bursts as a function of frequency and time are sometimes observed in their dynamic spectra. This fine structure enables determination of the shock thickness of the order of a few hundred to a few thousand kilometers. In a few cases, an interaction between streams of fast electrons and propagating shocks is clearly evidenced by simultaneous observations of short duration narrow band structures in type III bursts and type II bursts.
Dynamics of Coronal Transients: Two-Dimensional Non-Plane MHD Models
Authors: Nakagawa Y. , Wu S. T. , Han S. M.
Published: July 2016

Numerical results are obtained for non-plane MHD responses to a sudden energy release in a stratified model atmosphere. In agreement with observations, it is shown that after the energy release, the magnetic field affected by the energy release relaxes toward the potential configuration while the outer atmospheric fields increase its shear. Additional results suggest a new way of interpreting the energy storage and release in repeated flares.
Observations of Interplanetary Scintillation and a Theory of High-Speed Solar Wind
Authors: Washimi H. , Kakinuma T. , Kojima M.
Published: July 2016

It has been confirmed that the high-speed solar wind flows out of the coronal holes at low latitudes, where the magnetic fields open and the temperature is low (e.g., Krieger et al. 1973). But there has not been direct observation of the solar wind out of the polar regions of corona. We report here that the observations of interplanetary scintillation (IPS) show the existence of the high-speed flow of 800 km/s out of the polar coronal regions and the well-coincidence to the model of the coronal holes extending from the polar regions.
Automated Faint Galaxy Counts and Galactic Evolution
Authors: Tyson J. Anthony , Jarvis John F.
Published: July 2016

Detection and classification of faint images by eye has traditionally encountered systematic errors faintwards of 20th mag on Schmidt plates and 22nd mag on 4-meter plates. Automated classification of Schmidt plate images has pushed the classification limit to 22 mag (Kibblewhite, et al., 1975). Automated detection and classification of faint 4-meter limit plate images has recently led to statistical studies of galaxy numbers and clustering at redshifts where cosmology and galactic evolution dominate over local effects. Here we report on some aspects of the FOCAS (Faint Object Classification and Analysis System) automated classifier (Tyson and Jarvis, 1979) and compare our results of number counts in SA57 with those of Kron, 1979. Differential galaxy counts in six high latitude fields and evidence for galaxy evolution are briefly discussed.
Analyses of Deep Galaxy Samples
Authors: Ellis Richard S.
Published: July 2016

The combination of deep photography using fine-grain emulsions and fast automated plate-measuring machines is proving to be a valuable tool in studying galaxy evolution. Until recently, the favoured method for monitoring evolution was the spectroscopic study of one type of galaxy at various redshifts (see Spinrad 1977 for a review). It is considerably more economical, however, to derive evolutionary information from the statistical properties of the numerous faint images detectable on deep plates. The drawbacks are that the data at each apparent magnitude involves galaxies of different types seen over large redshift ranges. Also to interpret the statistics, we need to know the properties of large numbers of galaxies, for example their luminosity function, ultraviolet spectra and, particularly, the morphological variations in such properties.
Spectroscopy and Photometry of Faint Galaxies: Hints at their Evolution
Authors: Spinrad Hyron
Published: July 2016

I discuss four optical methods to locate standard candles (giant E galaxies), which should eventually lead us to reasonably large samples at high z. Redshift criteria and determinations are briefly discussed. The observed faint galaxy colors fit well into a simple model of stellar (galactic) evolution for systems with star-formation confined to a short time interval. Finally a summary of the statistics of blue galaxies in Coma-like clusters (Butcher-Oemler effect) is presented and interpreted.
The Dynamics of Superclusters
Authors: Ford Holland , Harms Richard , Bartko Frank , Ciardullo Robin , Eason Erik
Published: July 2016

Relatively little is known about superclusters. Observations of superclusters should increase our understanding of these grandest aggregates of matter and may tell us a great deal about the large scale distribution of matter in the Universe. We report here observations of two superclusters chosen from the list by Murray et al. (1978, Ap. J. [Letters], 219, L89).
The Origin of Absorption Spectra in Quasi-Stellar Objects
Authors: Weymann Ray J.
Published: July 2016

A classification scheme for QSO absorption line spectra is described which ascribes the origin of the lines to at least four mechanisms: (A) Explosive ejection of material at speeds up to 0.1 c. (B) Absorption by highly ionized material moving in a rich cluster in which the QSO is embedded. (C-1) Cosmologically distant intervening material with ‘normal’ abundances, probably associated with large galactic halos. (C-2) Cosmologically distant intervening material consisting of primordial uncondensed gas. Examples of each type of spectra are given and their ionization and other spectral characteristics discussed. The similarity between the development of novae spectra and a possible evolutionary sequence of the explosive ejecta of type A is striking and suggestive. Several difficulties and unsolved problems involving this scheme are noted. Finally, we speculate on the interpretation of two interesting objects (PKS 0237-23 and the ‘twin quasars’ 0957+56A,B) in the context of this scheme.
Anomalous Redshifts of QSOs
Authors: Narlikar J. V. , Das P. K.
Published: July 2016

The evidence for association of high redshift QSOs with low redshift galaxies is subject to controversies. If it can be convincingly argued that the observed associations are accidental and could occur with reasonably high probabilities (say > 5%) then the cosmological interpretation of the redshifts of QSOs remains unaffected by the data. If, however, there is increasing evidence, either statistically or in direct physical terms, for these associations to be real, then the excess redshifts of the QSOs become anomalous. Taking the latter alternative seriously, a suggestion was made by Narlikar (Annals of Physics, 107, 325, 1977) that the anomalous redshift of the QSO in a typical QSO-galaxy pair could arise because the particle masses in the QSO were systematically smaller than those in the companion galaxy, as predicted by a theory of gravitation based on Mach's principle. One astrophysical consequence of this effect is that the QSO should appear younger than the galaxy.
VLA Observations of the Double Quasar 0957+561: Gravitational Double Image or Binary Quasar?
Authors: Roberts D. H. , Greenfield P. E. , Burke B. F.
Published: July 2016

The radio source 0957+561 was identified by Walsh et al. (1979, Nature 279, pp.381–384) with a pair of quasars, 6.1 apart on the sky, whose optical emission and absorption spectra are nearly identical. Walsh et al. suggested a gravitational lens interpretation in which a single object is split into two images by an intervening massive object. Using the Very Large Array of the NRAO we have made a 6-cm wavelength radio map of 0957+561. The map shows unresolved sources of 36 and 30 mJy coincident with the optical N and S quasars, and a complex extended source of ~130 mJy (Roberts, Greenfield, and Burke: 1979, Science August 31). The extended emission lies on an arc containing the N quasar, and consists of two resolved sources containing 75 and 28 mJy, located 5.8 and 5.6 NE of the N quasar, a weak source of ~10 mJy about 5.5 SW of the N quasar, and a suggestion of a bridge connecting the NE and SW sources and the N quasar. There is no evidence of radio emission from a massive object between the two quasars. Although the existence of the extended source does not rule out a gravitational lens model for 0957+561, the underlying source required would have an unusual morphology. In addition, if the refracting object is at the redshift of the absorption seen in both quasars, its mass would have to be at least 2 × 1014 solar masses. Further observations at the VLA could rule out the gravitational lens model for 0957+561 if a second image corresponding to the NE extended component is not found.
The Radio Properties of BL Lacertae Objects
Authors: Weiler Kurt W.
Published: July 2016

A recent study of the properties of BL Lacertae Objects at λλ6 and 21 cm by K.J. Johnston and myself has shown:
Measurements of the Scattering of the Microwave Background Radiation in Clusters of Galaxies
Authors: Birkinshaw M.
Published: July 2016

Results for the decrements in the microwave background radiation towards the centres of 13 clusters of galaxies are presented. It is shown that these data imply central gas densities of about 2 × 10−24 kg m−3 and cluster masses of about 5 × 1045 kg.
Large-Angular-Scale Anisotropy in the Cosmic Background Radiation
Authors: Smoot George F.
Published: July 2016

Measurements of the large-angular-scale anisotropy of the cosmic background radiation made from the northern hemisphere are in essential agreement with each other and indicate a first order spherical harmonic component with an amplitude of approximately 3 mK. New data from the southern hemisphere support these previous results. This first order anisotropy is interpreted as resulting from the motion of the solar system relative to the cosmic background radiation. There is no evidence of any higher order anisotropy to the level of 1 mK.
Recent Developments in Improving Daytime Angular Resolution from the Ground
Authors: Kiepenheuer K. O.
Published: July 2016

The subject of this symposium is the fine structure of the solar chromosphere. Progress in this field of reserach will depend to a high degree of the quality of seeing, resp. on the effective angular resolution available on the ground. Today's situation of solar ground seeing has changed distinctly in the last years. I would like to report here a few new aspects, which could be condensed into 3 questions:

(1)

Are there on the ground ‘good seeing windows’, comparable in quality with stratosphere results obtained from balloon borne equipment?

(2)

Is there a chance to resolve from the ground the solar scale height, corresponding to about 0.1″.

(3)

Is there a residual fundamental atmospheric seeing noise resp. a basic limit to the atmospheric Modulation Transfer Function (MTF)?
Hα Fine Structure and the Dynamics of the Solar Atmosphere
Authors: Deubner Franz-Ludwig
Published: July 2016

Series of simultaneous spectra in different spectral regions, representing all ‘visible’ layers of the solar atmosphere, of high spatial and temporal resolution are used to compute power spectra and diagnostic diagrams of intensity and velocity fluctuations in order to study the dynamic response of the chromosphere to disturbances from below.
On the Improvement of the αδ System of the FK4 Catalogue
Authors: Anguita C. , Carrasco G. , Loyola P. , Naumova A. A. , Nemiro A. A. , Polozhentsev D. D. , Polozhentseva T. A. , Shishkina V. N. , Taibo R. , Timashkova G. M. , Varin M.P. , Varina V. A. , Zverev M. S.
Published: July 2016

About 45 000 absolute and semi-absolute observations of right ascension of the FK4 stars were obtained during 1963–1972. The observations were made with the three instruments of the Cerro Calán Observatory jointly by Chilean and Soviet astronomers. As a result, systematic δαδ cosδ errors were found to exist in the FK4 catalogue. For the reduction of star observations according to the SRS program, it is necessary to derive the system of the δα corrections for the FK4.
Absolute Determination of Right Ascensions of Stars at High Geographical Latitude during the Polar Night
Authors: Petrov G. M.
Published: July 2016

It is proposed that transit observations on the islands of Spitsbergen (φ = 78°) and Ross (φ=− 78°) be organised in order to determine absolute right ascension by observing continually throughout the polar night.
Southern Reference Star Program: Progress Report
Authors: Schombert J. L.
Published: July 2016

The observational programs for the Southern Reference Star Program are rapidly drawing to a close. Observations have been completed, except for a few at San Juan and a small percentage of zone −52° to −64° at the Cape. The Cape zone −64° to − 90° has been cancelled. The current state of the observations is shown in Table I.
Mouvements propres des etoiles de repere du catalogue photographique
Authors: Bouigue R.
Published: July 2016

Résumé. On examine le problème de l'obtention des mouvements propres à partir des observations meridiennes effectuées dans différents Observatoires, en vue de la détermination de la précision que l'on peut attendre de ces résultats.
Positions of Extragalactic Radio Sources from Very Long Baseline Interferometry
Authors: Counselman C.C.
Published: July 2016

The positions of extragalactic radio sources have been determined by very-long-baseline interferometry with uncertainties smaller than 0″.1, and fundamental limits on the accuracy of VLBI astrometry have not yet been reached. Technical improvements within the next five years may enable positions to be determined by VLBI with uncertainties of 0.″005.
Accuracy Estimation of Astronomical Constants from Long Baseline Interferometer Observations
Authors: Walter H. G.
Published: July 2016

Inherent in Very Long Baseline Interferometry (VLBI) is the potentiality of determining relative angular positions of radio sources to an accuracy which is superior to present methods by at least one order of magnitude. For VLBI observations such as time delay, fringe frequency and fringe phase the sensitivity to the uncertainties of astronomical constants and geophysical parameters, i.e. luni-solar precession, nutation constant, rate of change of obliquity, polar motion and Earth rotation, is investigated.

The partial derivatives of the observations with respect to these unknowns form the core of the estimation process and give evidence of the influence of the source position and the baseline geometry on their magnitudes. By means of a variance-covariance analysis the standard deviations and the cross correlation coefficients of the unknowns are derived. It is inferred from them that VLBI observations are not only sensitive to variations in the astronomical constants and geophysical parameters, but that the effects caused by these variations are also measurable and separable, if the observations are extended over a sufficiently long interval of time, and the baselines and source positions are chosen appropriately.
The Texas Radio Astrometric Survey
Authors: Douglas James N.
Published: July 2016

The 5-element Texas Interferometer is engaged in a 365 MHz survey of the sky with a primary goal of establishing positions of about 50000 discrete radio sources with an accuracy of about 1″ in each coordinate. Measurements are made relative to optical positions of identified sources, and the 2000 positions thus far obtained support our expectations of the accuracy of the survey. In a companion program, optical positions of objects near radio source positions are being measured to ±1/2″ accuracy on glass copies of the Palomar Sky Survey, yielding both improved overall calibration of the radio positions and identification of associated optical objects on the basis of position coincidence alone, without the selection effects usually introduced by auxiliary identification criteria.
The Palomar Proper Motion Survey
Authors: Luyten W. J.
Published: July 2016

The present state of the Palomar Proper Motion Survey is described. Before the CDC automated-computerized plate scanner became operational in 1972, 153 plate pairs had been blinked, whereas since then 443 pairs have been machine processed. Of the remaining 350 fields, some 40 are probably beyond the capability of the present system due to excessive star density.

Some 21000 new motions larger than 0″.18 annually have been published. The accuracy of an individual motion is about ± 0″.016 from a single machine-processed plate pair, as compared with ± 0″.025 from hand measured plates.

There is an indication that the number of large motions per unit area increases with galactic latitude.
Reduction of Schmidt Photographs with the Aid of Reference Marks on the Curved Plate
Authors: Lacroute P.
Published: July 2016

A method is proposed for improving the astrometric accuracy obtainable from curved-field Schmidt plates. A reseau of small crosses in a 10 mm-spaced rectangular grid is imposed on the plate while still curved in its holder. The reseau is calibrated by photography of a field of reference stars with known positions. The method eliminates the troublesome errors arising from uncertainty in the nature of deformation of the curved plates.
Proper Motions with respect to Galaxies (Invited Paper)
Authors: Deutsch A. N. , Klemola A. R.
Published: July 2016

At Lick the second phase of the proper motion program is in progress. In addition to generally selected stars, as was done for the first phase, so far over 30000 stars of special types of astro-physical interest and about 29000 AGK3 stars have been selected for measurement.

In accordance with the Pulkovo program, second-epoch photography with galaxies is being continued at Pulkovo, Moscow and Tashkent, and proper motions with reference to galaxies are derived.

Analyses of proper motions at Pulkovo and Lick show agreement in some instances and disagreement in others. The same applies to comparisons with fundamental catalogues. The analyses suffer to some extent from absence of proper motions in the zone of avoidance and in the southern part of the sky.

In the southern hemisphere, first-epoch photography of 164 fields with galaxies has been completed using the Maksutov double-meniscus telescope at Cerro El Roble in Chile, and a complete coverage of the sky has been started with the same telescope; this work is being done jointly by the Soviet and Chilean astronomers. On the Yale-Columbia southern program, the first-epoch photography is nearly completed with the double astrograph at Leoncito in Argentina. There are plans at Lohrmann Institute, Dresden, to take photographs with the 2-m Schmidt telescope at Tautenburg, thus providing first-epoch plates for proper motions with reference to galaxies.
Comparison of Secular Parallaxes Determined from Proper Motions of Stars Relative to Galaxies at the Pulkovo and Lick Observatories
Authors: Fatchikhin N. V.
Published: July 2016

The secular parallaxes, determined by Klemola and Vasilevskis from proper motions of stars relative to galaxies (Klemola and Vasilevskis, 1971), were interpolated in latitude for each area of the Pulkovo Catalogue (Fatchikhin, 1974). Then the mean values were grouped in three zones of galactic latitude (b) and the data obtained at the Lick Observatory (L) were compared with our data (P) (Fatchikhin, 1972, 1973). The results are given in the Table I.
Progress Report on the Herstmonceux Progamme of Measurement of Proper Motions in the Northern Selected Areas
Authors: Murray C. A.
Published: July 2016

First results of the Herstmonceux programme of redetermination of proper motions in the Selected Areas are presented. Plate material includes the old Radcliffe plates, old plates taken at Greenwich and modern plates taken on the 26-in. refractor at Herstmonceux. The plates are being measured on GALAXY and reduced according to the plate-overlap technique.
Sur la mesure des distances par telemetrie laser
Authors: Bouigue R.
Published: July 2016

On fait une analyse des différents procédés de mesure des distances dans le système solaire et dans son voisinage en vue de mettre en évidence les différentes corrections que ces mesures peuvent nécessiter.
Astrometry with the Large Space Telescope
Authors: van Altena W. F. , Franz O. G. , Fredrick L. W.
Published: July 2016

The Large Space Telescope (LST), planned to be launched in 1980, will give an opportunity for astrometric observations of high quality to be secured.

A detailed survey is presented of the potentialities of the LST for studies of proper motions, parallaxes, star clusters, double stars, perturbed motion stars, occultations, fundamental astrometry and solar system observations.

The proposed characteristics and design capabilities of the LST are tabulated.
The Origin of the Asteroid Ring
Authors: Gąska S.
Published: July 2016

From extended statistical investigations of the orbital elements of asteroids and of their dispersions it is found that the relations for some of the dispersions are stable and are regarded to be invariable. By assuming that the orbital elements derived by putting the dispersions equal to zero correspond to those of the mother planet of the asteroid ring, it is found that the mother planet is Mars.
Comet Schwassmann-Wachmann 3 (1930 VI)
Authors: Belyaev N. A. , Shaporev S. D.
Published: July 2016

The definitive orbit of comet 1930 VI basing on 190 observations has been derived. Investigation of the comet orbit evolution for the time span of 200 yr indicated that the 1882 approach (tappr = 1882 Oct. 22.559; δmin = 0.0057 AU) of the comet to Jupiter resulted in considerable element transformations. The perihelion and aphelion distances reduced from 4.1 AU to 1.2 AU and from 12.2 AU to 5.2 AU, respectively, whereas the period of revolution also underwent a decrease from 23.3 yr to 5.8 yr. The next return of the comet to the perihelion is to be expected in 1974 (T= 1974 March, 17.475).
Conditions for Escape and Retention
Authors: Griffith J. S.
Published: July 2016

The methods used in deriving conditions for escape, retention and containment for the three-body problem are applied to the n-body case, and similar conditions are obtained. In the n-body problem less stringent conditions are derived, and in the case of retention a further condition is imposed.
Influence of the Dynamical Figure of the Moon on Its Rotational-Translational Motion
Authors: Eroshkin G. I.
Published: July 2016

The influence of the dynamical figure of the Moon on its rotation with respect to its mass centre (the physical libration) is determined by means of the theorem on the angular moment of a rigid body. In the expansion of the Moon's force function in spherical harmonics all the second and the third order harmonics are taken into consideration. For the determination of the Moon's physical libration components a linear system of differential equations of the second order with constant coefficients is constructed.

The integration displays the essential influence of the new terms in the force function expansion. For evaluation of the disturbed elements of the lunar orbit due to the nonsphericity of the Moon's dynamical figure the Lagrange's equations are solved. The disturbing function is taken in an expansion form in powers of the eccentricity of the lunar orbit and of the inclinations of the Moon's equator and its orbit with respect to the ecliptic. The commensurability of the Moon's mean motion and its angular velocity of rotation produces in the major semi-axis of the lunar orbit secular perturbations of the first order.
On the Stability of Small Clusters or Cluster Remnants
Authors: Lodén L. O. , Rickman H.
Published: July 2016

There is strong evidence that the occurrence of mutually very nearby stars with identical spectral type and apparent magnitude is in many cases appreciably more frequent than one has reason to expect if there should only be a case of pure random combination. This phenomenon might be associated with the problem of stability of small stellar systems, if we can identify a certain number of the coincidences as some sort of cluster remnants. Besides the fact that there are several physical explanations of the coincidence phenomenon without consideration to dynamical stability conditions, there is also more than one stability aspect which may be regarded as reasonable. In the first instance we have to survey the possibilities that the stability of certain conglomerations of stars - particularly those with two components - may depend on the mass relation and will reach a maximum value for equal masses. As most straightforward we regard the conception that the most massive stars in a cluster (or even a multiple system) form the most stable and hence the most long-lived configuration, so that a cluster remnant most probably will consist of stars of rather equal mass.
The Dynamical Evolution of Trapezium Systems
Authors: Allen C. , Poveda A.
Published: July 2016

To study the dynamical evolution of trapezia, the equations of motion of the member stars in 30 different trapezia were integrated numerically. It was found that two-thirds of the trapezia still remain as such after 106 yr. Thus, the dynamical ages of trapezia containing O-stars are only slightly shorter than their nuclear ages. The properties of the binaries formed during the computations are studied. The numerical results are discussed from the observational point of view.
On the ‘Thermodynamics’ of Self-Gravitating N-Body Systems
Authors: Miller R. H.
Published: July 2016

Results of some simple ‘thermodynamic’ experiments on self-gravitating n-body systems are reported for a variety of boundary conditions. Systems placed in specularly reflecting enclosures did not show any unusual behavior, even though a variety of conditions was tried in an attempt to start a ‘gravothermal castastrophe’. Similarly, there was no tendency to transfer energy between ‘hot’ and ‘cool’ subclosures within a given cluster. However, systems in ‘isothermal’ enclosures gave up energy to the enclosure at a surprisingly high rate, and sustained the energy-transfer rate as long as the experiment was continued. An explanation of these different behaviors was sought and found in an examination of the premises that underlie certain attempts to construct a thermodynamics for self-gravitating systems. Conventional application of the H-theorem implies violations of the n-body equations of motion and predictions not consistent with observation. Both the ‘gravothermal catastrophe’ and the experiments in an ‘isothermal’ enclosure share this violation of the equations of motion. A new formulation that allows for all the interactions in an n-body system shows that isolated n-body systems need not form binaries or condense into other subaggregates. The virial theorem follows as an ensemble average over the micro-canonical ensemble.
Holes in the Solar Corona
Authors: Glencross W. M.
Published: July 2016

Babcock (1961) outlined the sequence of events which takes place in the Sun's atmosphere during a solar cycle. Magnetic field loops, having preferred directions, emerge from the solar surface and thereafter merge with neighbouring loops to produce more extended structures. Although flux tubes emerge with a strong E-W field component, having the field direction reversed from one side of the equator to the other, there is a tendency for the longer loops produced by merging to have a significant N-S alignment (Hansen et al., 1972).
X-Ray Spectra of Solar Active Regions
Authors: Parkinson John H.
Published: July 2016

The last few years have seen great progress in our understanding of X-ray spectra of solar active regions. This paper demonstrates both the usefulness and the limitations of the techniques, both scientific and instrumental, that have recently become available. Improvements in spectral resolution led to the discovery of weak satellite lines to helium-like ions; the quantitative theory for these lines is also discussed. The observed intensities of the Fe XVII lines are also investigated and found to be in agreement with calculations that allow for cascading processes.
Association of X-Ray Flares with Solar Coronal Active Regions
Authors: Sengupta P. R.
Published: July 2016

It is known that the flare component of solar X-ray emission is sensitive to the level of solar activity. The location of the X-ray flaring region is not directly known but can be inferred from the location of the associated Hα flare. A detailed study of more than 4000 solar X-ray flares recorded by UI and the NRL detectors during past eight years has shown that 85% of these flares definitely occurred in the active regions. For the rest 15% no definite conclusion was possible because either Hα flare data was not available or no Hα flare was reported within ± 15 min of these X-ray flares.
The Relationship between Hard and Soft X-Ray Bursts Observed by OSO 7
Authors: Datlowe Dayton W.
Published: July 2016

Solar X-rays in the energy range 1–100 keV originate in hot plasmas and streams of energetic electrons in solar flares, and since these phenomena may represent a significant fraction of the energy in a flare, an understanding of them is important for any flare theory. This paper presents the results of the University of California, San Diego, solar X-ray instrument on the OSO-7 satellite. Study of the time evolution of the emission measure in a typical burst indicates that the growth of soft X-ray emission is due to the addition of new hot material to the flare plasma, and the study of the time evolution of the temperature of the plasma indicates that conduction is the dominant cooling mechanism. Comparison of the hard (10–100 keV) and soft (5–10 keV) data indicates that the main heat input to the flare plasma is not collisions by the electrons which make the hard X-rays. The fraction of soft X-ray bursts observed by the instrument which also have a detectable hard X-ray component is this result is the same for bursts which occured near the center of the disk (θ < 60°) and for those bursts believed to have been partly occulted by the limb, indicating that hard X-ray emission comes at least part from high in the corona. For a sample of 62 hard X-ray bursts which occurred near or beyond the limb, the spectral index of the hard X-ray power law was significantly larger, as compared with the spectra of a comparable number which occurred at solar longitudes less than 60°.
Thermal and Nonthermal Interpretations of Flare X-Ray Bursts
Authors: Kahler S.
Published: July 2016

Various authors have presented arguments for either the thermal or the nonthermal interpretations of impulsive E > 20 KeV X-ray bursts and slowly varying E < 10 keV X-ray bursts. In this review the arguments for and against the prevailing opinion that the impulsive bursts are nonthermal and the slowly varying bursts are thermal are presented.

For the impulsive bursts we discuss the spectra, electron mean free paths, center-to-limb distributions of both the numbers of events and spectra of events, and polarization data as relevant criteria. For the slowly varying events we discuss electron self collision times, distribution of X-ray temporal parameters, associated gradual rise and fall radio bursts, spectral and time profiles of special events and center-to-limb distributions of numbers of events as the relevant criteria.
On the Acceleration Processes in Solar Flares
Authors: Švestka Z.
Published: July 2016

The paper summarizes what we know about the acceleration processes on the Sun. Four different instabilities are distinguished: (1) One with purely thermal consequences giving rise to the origin of any flare. (2) A non-thermal process at the flash phase of flares giving rise to ∼ 100 keV electrons and protons, manifested through hard X-ray and impulsive microwave bursts (current interruption?). (3) An instability giving rise to streams of electrons, without accelerating protons, manifested by type III bursts (tearing-mode instability?). When (2) and (3) are linked, flare associated electron events in space are often recorded. (4) Finally an explosive instability produces a shock wave which manifests itself as a type II burst. This instability leads to a second-step acceleration of particles preaccelerated in (2) and gives origin to >10 MeV protons and relativistic electrons (probably stochastic acceleration).
On the Identification of Mm-Wavelength U-Lines
Authors: Turner B. E.
Published: July 2016

During the past five years, a total of about 180 U-lines has been observed by the author and others in the 70-115 GHz region in the prominent molecular clouds Sgr B2 and Ori (KL). A program to identify the carriers of these lines has been undertaken. A computer code, incorporating nine different centrifugal distortion Hamiltonians, generates spectra of asymmetric rotors from given rotational and centrigugal-distortion constants. Spectra have been computed for ∼550 molecules that are considered potentially interesting astrophysically. Molecules were selected from Landolt-Bornstein Volumes IV (1967) and VI (1974) on Molecular Constants, and from the spectroscopic literature (1973 - present).
The Relative Distribution of Ammonia and Cyanobutadiyne Emission in Heiles 2 Dust Cloud
Authors: Little L. T. , Macdonald G. H. , Riley P. W. , Matheson D. N.
Published: July 2016

A map of the NH3 (1,1) emission in Heiles 2 dust cloud, observed with 2.2 arc min. resolution, is presented and compared with that of the J = 9 → 8 transition of HC5N. Although the distribution of both molecules lies on a ridge, there is a marked anti-correlation in the observed antenna temperatures of the two molecules along it. This appears to be best explained as a variation in the relative abundances of the two molecules along the ridge by a factor 8-20 in a distance of 1018 cm.
C2H and HC3N in Interstellar Clouds
Authors: Wootten Alwyn , Bozyan G. P. , Garrett D. B. , Loren R. B. , Snell R. L. , Bout P. Vanden
Published: July 2016

A survey for the molecules C2H and HC3N in a variety of interstellar clouds has been completed. Both molecules are very widespread, in cold dark clouds as well as in hot clouds. C2H emission has been mapped in L1534. In cold clouds the fractional abundance X(C2H) is found to be 2-6×10−9. The ratio of abundances X(C2H)/X(HC3N) falls in the range 6-10, consistent with some gas-phase reaction schemes for these molecules.
CO and OH in the Galactic Center Region
Authors: Inatani Junji , Ukita Nobuharu
Published: July 2016

The two-dimensional distribution of molecular clouds in the galactic center region has been investigated in the CO 115 GHz line and in the OH 1665 and 1667 MHz lines. As the former is an emission line, we can find molecular clouds without the unavoidable bias to continuum sources which is inherent in a survey of OH absorption lines. Because the CO line is usually optically thick, the brightness temperature of the line is directly related to the kinetic temperature of the cloud. On the other hand, the real optical depth of the OH line can be obtained from the intensity ratio between 1665 and 1667 MHz lines (assuming LTE). From this point of view we have compared the CO and OH observational results.
Ammonia Observations of Dark Clouds Containing Herbig-Haro Objects
Authors: Ho Paul T.P. , Barrett Alan H.
Published: July 2016

A study in NH3 was conducted towards H-H objects. Cloud fragmentation appears to have occurred in the regions mapped. Rotation is present with velocity gradients of 1-2 km s−1 pc−1. We suggest that in the regions containing H-H objects, formation of stars of different spectral types may be taking place.
Columbia CO Survey: Molecular Clouds and Spiral Structure
Authors: Cohen R. S. , Dame T. M. , Thaddeus P.
Published: July 2016

We have recently completed at Columbia University a survey with a 1.2 meter telescope of 2.6 mm CO emission from the first galactic quadrant. The beamwidth of this telescope − 7.5′ at 2.6 mm - is optimal for a large-scale galactic survey: it is as small as that of the best 21-cm surveys but not so small that undersampling is required to finish a survey in a few hundred days of observing. The survey contains more than 3000 spectra between longitudes 12°and 60°and latitudes −1°and +1°. Spectra were taken every beamwidth for |b|≤0.25° and every two beamwidths elsewhere. Integration times, which averaged about 8 minutes, were adjusted to give an rms noise level of 0.3 K per 0.5 MHz spectral channel.
Observations of Interstellar Molecules with the International Ultraviolet Explorer
Authors: Black John H.
Published: July 2016

The ultraviolet spectra of 25 early-type stars have been obtained with the International Ultraviolet Explorer observatory. Bands of the 4th-positive system of interstellar C0 are seen towards 12 of these stars. Spectra of HD46223 have been examined for interstellar lines of CH, C2, CH2, OH, HC1, and H2O.
Interstellar Line Spectra of a Dense Cloud: The VI Cygni Association
Authors: Souza Steven P. , Lutz Barry L.
Published: July 2016

Spectroscopic observations of the dense interstellar cloud which obscures the VI Cygni association have yielded an optical map of the atomic and molecular constituents in a region which may represent a transition between the diffuse and radio clouds. The velocity of the optical components found is consistent with that of a CO cloud seen in front of No. 12.
Formation of Simple Molecules by C+ Reactions on Oxide Grains in Diffuse Clouds
Authors: Duley W. W.
Published: July 2016

The reaction between C+ ions and OH- ions on the surface of oxide or silicate grains in diffuse clouds is shown to be a source of CH, OH, CO, HCO and H2CO molecules.
Molecular Synthesis in Interstellar Clouds: the Radiative Association Reaction H + OH ↠ H2O + hv
Authors: Field D. , Adams N. G. , Smith D.
Published: July 2016

On the evidence of some recent laboratory data for the association reaction H + OH + He → H2O + He, and following previously proposed ion-neutral association reaction schemes, we tentatively suggest that the radiative association reaction of H and OH can be a significant mechanism for the production of H2O in interstellar clouds, when compared with the ion-neutral reaction sequence. The ‘H-atom + radical’ association process may be of some general importance in the production of other small molecules in interstellar clouds.
Molecule Formation in Cool, Dense Interstellar Clouds
Authors: Watson William D.
Published: July 2016

A discussion is given of the general processes and considerations that arise in attempting to understand molecular reactions in cool, dense interstellar clouds. Basic elements of the gas phase, “ion-molecule” scheme are given explicitly before surveying topics in which there is considerable current activity. These topics include: (i) refined comparisons of prediction and observation for species of “intermediate” complexity, (ii) numerical computations of cloud models which include numerous chemical reactions and molecular species, (iii) formation of the complex molecules, (iv) isotope fractionation in interstellar molecules and (v) possible contributions from chemistry in shocks.