bluuebunny/crossref_metadata_2025 huggingface dataset:
The Boundary between the Magnetic Fields of Ap Stars and the Fields of Solar-type Stars
Authors: Landstreet John D.
Published: July 2016

The boundary between Ap-type magnetic fields and the magnetic fields of solar-type stars occurs near Te ~ 7000K, about where deep envelope convection develops in main sequence stars. This seems natural for solar-type stars, in which the field is generated by the convection zone. However, among magnetic Ap stars the frequency of occurrence declines from about 10% of all A stars near A0 to about 1% near F0. It is not clear what produces this decline in frequency, but the convection zone is probably not responsible. In fact, it seems likely that if global fossil fields occur in main sequence F stars, such fields should be detectable even if the stars having them are not chemically peculiar.
Spectroscopic Analysis of HR 1099
Authors: Savanov I.S. , Tuominen I.
Published: July 2016

We have calculated synthetic spectra for HR 1099 for the wavelength region λ6425-6445 Å, which includes the Cal λ6439 Å and FeI λ6430 Å lines, often used for the surface imaging of rapidly rotating late-type stars. The best agreement between the theoretical and observed spectra can be achieved with solar abundances in the both components of the system, except for Ca in the primary. Theoretical calculations give the possibility of estimating the influence of microturbulence, damping and blending on Ca I and Fe I line profiles.
Observations Relating to Stellar Activity, Magnetism and Dynamos
Authors: Jordan C.
Published: July 2016

Dynamo theory can in principle be tested by comparing its predictions with a variety of types of solar and stellar observations. The progress apparent from papers presented at this Colloquium is summarized, and areas where further observations would be of particular value are stressed.
Diffusion of Silicon in Ap-Star Atmospheres
Authors: Gail H. P. , Sedlmayr E.
Published: July 2016

The diffusion problem of silicon in Ap-star atmospheres is treated numerically. Results for the depth dependence of the concentration and for the relevant time scales are presented. The influence of turbulent mixing on the diffusion process is briefly discussed.
The Rare Earths in the Peculiar A Stars: A Test Case for the Magnetic Diffusion Hypothesis
Authors: Shore Steven N. , Adelman Saul J.
Published: July 2016

A brief formulation and an overview of the magnetic diffusion mechanism is presented. The atomic physics of the rare earth spectra is considered. It is demonstrated that basic differences among these elements contribute to the observed abundance anomalies of rare earth elements. The ion fractions of the rare earth display very different behaviour with temperature and pressure. In the atmospheres of Ap stars, europium tends to have the greatest degree of ionization. While previous studies on the diffusion mechanism with model atmospheres have maintained chemical homogeneity, we argue that this is an unrealistic approach to the Ap stars and present the consequences in the light of the diffusion picture.
The Influence of Light Variations on the Stellar Magnetic Fields Measurements
Authors: Catalano F.A. , Strazzulla G.
Published: July 2016

In the frame of the oblique rotator the radiation field is assumed to depend on the magnetic colatitude. Introducing this dependence in the effective magnetic field formula, a new expression for this has been derived.

The calculations carried out in the case of a dipolar surface field having a polar intensity of 104gauss show that the amplitude of the variation and the polarity reversal both depend on the combination of the obliquity and inclination angles.
Near-Ultraviolet Observation Of Four Bright Mn Stars
Authors: Faraggiana Rosanna , van der Hucht Karel A. , Burger Marijke
Published: July 2016

Near-ultraviolet spectra, obtained with the ESRO TD-1A/S59 experiment, of the four Mn stars β Tau, γ Crv, α And and μ Lep and six normal stars are compared. The normal stars show good agreement with synthetic spectra. The Mn stars have spectra which become hotter at shorter wavelengths. They also show strong Mn II lines and weak Mg II lines. A time-variation for Ti II λ 2828 was noted in γ Crv and α And.
A High Dispersion Search For Peculiar A And B Stars
Authors: Dworetsky M.M.
Published: July 2016

All bright stars classified as normal B8-A0, luminosity class III, by Cowley et al. (1969) and Cowley (1972) have been examined on high dispersion spectrograms (10 and 20 Å/mm) obtained at Mt. Wilson in 1972 and 1973. Of 152 stars observed, 4 shell stars, 16 Hg or Hg-Mn stars, and 2 stars with other anomalies were found. Nine of these had previously been described as peculiar, although only four were in published sources at the time these observations were made.
Abundance Anomalies in am Stars and their Relation to Ap Stars
Authors: Khokhlova V.L. , Ptitsyn D.A.
Published: July 2016

The correlations of abundance anomalies of various elements in Am stars show continuous transition from normal through Am and Ap stars. There are poor correlations for some light elements and very good correlations for iron group and heavier elements. There is no obvious connection of the slope of correlation curves to ionisation potentials or opical term structure.
The Definition of the Terrestrial Coordinate Frame by Long Baseline Interferometry
Authors: Cannon W. H. , Rochester M. G.
Published: July 2016

This paper examines the question of the definition of the celestial and terrestrial coordinate frames by the technique of long baseline interferometry. It demonstrates how the celestial coordinate frame may be usefully defined in terms of basis 1-forms associated with the advancing phase fronts of the radiation fields from compact radio sources using only interferometer observables. The paper then proceeds to show how the terrestrial coordinate frame could be usefully defined, incorporating fully the effects of plate tectonics and secular motion of the observatories, by an application of the theory of continuum mechanics to interferometer observations.
The Effects of the Reference Frames and of their Realization on the Earth Rotation Parameters Computed from Different Observational Techniques
Authors: Capitaine Nicole , Feissel Martine
Published: July 2016

The inaccuracies in the reference frames actually realized by the different techniques for measuring the Earth’s rotation are theoretically investigated. The intercomparison of the available series of measurements provides numerical estimations of these defects. Using data corrected for reference frame effects high frequency fluctuations of UT1 are detected.
The Short Period Latitude Variations Derived from Recalculated Past ILS Observations
Authors: Manabe Seiji
Published: July 2016

Ten frequency components of short period latitude variations and corrections for the declination at an epoch and the proper motion in declination are estimated simultaneously. The short period variations are nearly diurnal and semi-diurnal and are supposed to be due to nutations and Earth tides. Analysis is by the least-squares chain method with weights for individual observations, recently developed by Manabe et al. (1977). Weights are assigned on the assumption that the observational errors follow a normal distribution, whose dispersion changes night by night. Among all possible 1024 combinations of the short period variations, the best is chosen on the basis of the minimum AIC procedure. The data used are the results of the homogeneous recalculation of the ILS observations, 1399-1978. This is considered to be the optimal astrometric data set for investigating nutations, because of its long time-span, homogeneity and size. Declinations are estimated for each of the seven observational periods with mean errors smaller than 001. The mean errors of the proper motions are of the order 0002/y. Among the short period variations, significant estimates are obtained for the terms corresponding to the lunar fortnightly, solar semi-annual and lunar nodal nutations, and the M2 tide. The mean errors are shown to be greatly reduced and the entire data set is analyzed. An effort is made to distinguish the preferred theoretical model.
Motions of Artificial Satellites and Coordinate Systems
Authors: Kozai Yoshihide
Published: July 2016

In order to compute satellite motions with centimeter accuracy, the reference system, to which they are referred, should be carefully chosen. In fact there are many kinds of the reference systems. In this paper advantages and disadvantages of various reference systems are discussed.
Theoretical Evolution Sequences for Homogeneous and Two-Zone Models of Delta Scuti Variables
Authors: Andreasen G. Kjærgaard , Hejlesen P.M. , Petersen J. Otzen
Published: July 2016

Radial pulsation periods are calculated for models of variables in the lower Cepheid instability strip. Evolution tracks in several diagrams are constructed and used for comparisons with observed periods, period ratios, and effective temperatures. These comparisons are simpler and more direct than in earlier studies with separate evolution and pulsation calculations.
Full Amplitude Models of 15 Day Cepheids
Authors: Cogan B.C. , Cox A.N. , King D.S.
Published: July 2016

Numerical models of Cepheids have been computed with a range of effective temperatures and compositions. The amplitudes increase if the helium abundance increases or if the effective temperature decreases. The latter effect is contrary to observational data. The models also exhibit velocity amplitudes which are much lower than those observed.
The Cepheid Luminosity Scale
Authors: Schmidt Edward G.
Published: July 2016

The distance moduli of galactic clusters containing classical Cepheids are being redetermined using the four-color and Hβ photometric system. The results for four clusters are presented here and it is found that the distance moduli are smaller than previous values. Possible reasons for this discrepancy are discussed.
Supernova Explosions - The Role of a Rayleigh-Taylor Instability
Authors: Buchler J. Robert , Livio Mario , Colgate Stirling A.
Published: July 2016

A two dimensional hydrodynamic study indicates that convectively unstable gradients which develop during core collapse and bounce give rise to large scale core overturn. It is also shown that the concomitant release of neutrini can deposit large amounts of energy and momentum in the infalling envelope and give rise to a powerful supernova explosion.
Neutron Star Formation by Collapse of White Dwarfs
Authors: Canal R. , Isern J. , Labay J.
Published: July 2016

Mass-accreting carbon-oxygen white dwarfs become thermally and dynamically unstable when they reach high enough central densities. Carbon ignition at the star’s center likely propagates subsonically and, in the case of an initially solid core, leads to collapse if the rate of increase of the core’s mass is sufficiently fast. Recent results indicate, however, that solidification of the core induces carbon-oxygen separation. The central regions are then made of pure oxygen while carbon is rejected to lower-density layers. Carbon ignition happens only after neutronization of the central (oxygen) regions. Collapse to a neutron star is then independent from the rate of mass increase and the only possible restrictions are set by the behaviour of the outer, accreted layers. X-ray sources, pulsars and Type I supernovae are likely outcomes of this process.
Thermodynamic Transport Properties in Dense Stars
Authors: Edwards Terry W.
Published: July 2016

The thermodynamic transport properties of special relativistic imperfect fluids, as found in dense stars, are investigated. These properties, which include thermal and electrical conductivities, electrothermal coefficients, and bulk and shear viscosities may be formulated in terms of the momentum distribution functions obtained from the solution of the Boltzmann transport equation. Spherical harmonic solutions of the relaxation form of the relativistic magnetic Boltzmann transport equation have also been obtained which give the non-equilibrium momentum distribution function perturbation f-f(0) = Δf(p) in terms of electromagnetic and thermal fields.
The Voyager Encounter with Uranus
Authors: Stone E. C.
Published: July 2016

The Voyager 2 spacecraft is targeted for an encounter with Uranus in January, 1986. In addition to a brief description of the 11 scientific investigations and the Uranian encounter geometry, the scientific capabilities of Voyager 2 are discussed for the general areas of the atmosphere, the rings, the satellites, and the magnetosphere.
The National Space Science Data Center (NSSDC) and the World Data Center A for Rockets and Satellites (WDC-A-R&S): Their Role in X-Ray Astronomy Data
Authors: Locke M. C.
Published: July 2016

The combined role of NSSDC and WDC-A-R&S in collecting, preserving and disseminating data from 10 years of X-ray observations is presented along with a brief history of the organizations.
Stellar bibliography retrieving system in Japan
Authors: Nishimura Shiro
Published: July 2016

On-line retrieving systems of BSI in Japan is briefly described. The BSI reference file was adapted to be retrieved by some keywords other than star names. Then the retrieval system of BSI was constructed on a general retrieval language CIR. Some efforts to make the system efficient and to save the disk space are discussed.
Current progress with the Double Star Catalogues
Authors: Worley Charles E.
Published: July 2016

Current progress on the visual double star Index and Observation Catalogues is discussed. In addition, a new edition of the visual binary orbit catalogue is being prepared.
Metacatalogue of galaxies and large scale structures in the Universe
Authors: Kalinkov M.
Published: July 2016

The present state of the compilation of the Metacatalogue of galaxies is described by Kalinkov et al. (1981). The preparation of the catalogue originated from the necessity to put on magnetic tape Zwicky’s catalogue in order to study the distribution of galaxies and clusters of galaxies. Enlarging the Metacatalogue by joining to it other catalogues, some interesting results for the large scale structure in the Universe have been obtained. New methods for efficient data processing have been developed for smoothing and filtering of discrete fields, for computing the two-cell correlation function and its matrix representation to test homogeneity and isotropy, and so on (Kalinkov, 1974, 1976, 1977).
Honeycomb Mirrors of Borosilicate Glass; Current Results and Plans for 7–8m Diameter
Authors: Angel J.R.P. , Arganbright D. , Harmonson L. , Hill J.M. , Woolf N.
Published: July 2016

The case for making large mirrors for astronomy with borosilicate glass honeycomb structure has been made in an earlier paper (Angel and Hill, 1981). Honeycomb structure gives rigidity in a lightweight mirror as well as low thermal inertia. Mirrors which are in thermal equilibrium with the air hold the promise of better images, since convection at the mirror is eliminated. Thermal expansion of borosilicate glass is problematical in thick mirrors which are likely to be out of thermal equilibrium and hence distorted. This will not be a problem in honeycomb mirrors with thermal time constants of only a few minutes. We believe a single casting technique holds the greatest promise of making borosilicate honeycomb mirror blanks up to 7 meters in diameter. Our work to develop the technique now involves casting test blanks 60cm in diameter but which have the full thickness (33cm), cell size (15cm) and faceplate thickness (2.5cm) needed for a 1.8m mirror.
The Catadioptric Camera as Used for Astronomical Spectroscopy with Image Tubes and Similar Detectors: A Limited Review
Authors: Harmer C.F.W.
Published: July 2016

This paper compares the two major types of catadioptric camera, viz. the Maksutov camera and the Schmidt camera, when used for astronomical spectroscopy in instruments dedicated to image tubes, diode arrays and similar types of detectors. The review is limited to the detailed description of systems with which the author has been personally involved, that is, they have either been made at RGO or represent RGO participation in external projects.
The past and future of 1983 TB and its relationship to the geminid meteor stream
Authors: Fox Ken , Williams Iwan P. , Hunt J.
Published: July 2016

It is now well known that object 1983 TB, discovered by IRAS, has an orbit very similar to that of the Geminid meteor stream. Calculations show that this orbit crossed over the orbit of Venus about 500 years ago. We will describe calculations tracing the history of both the object and the stream through this interaction with Venus and the present interaction with the Earth.
The role op the researches of E.I. Kazimirchak-Polonskaya on the dynamical evolution of short-period comets
Authors: Belyaev N.A.
Published: July 2016

In 1961 Kazimirchak-Polonskaya (1961a, 1961b) published comprehensive reviews of all investigations on the dynamics of cometary orbits as well as on close approaches of the short-period comets with Jupiter for the time span covering 1770–1960 and for the first time put forward the basic problems of cometary astronomy from the standpoint of celestial mechanics. Chebotarev (1971) pointed out that “these reviews, supplemented with extensive references, can serve as a valuable manual for all researchers of cometary motions”. In 1967 Kazimirchak-Polonskaya (1967a) developed the advanced problems in a definitive form. The corresponding member of the USSR Academy of Science M.F. Subbotin (at that time the Head of the Institute) characterized the above mentioned works as “the general plan for cometary studies in the important branch of cometary astronomy”.
Zodiacal Light and Interplanetary Dust
Authors: Weinberg J.L.
Published: July 2016

Recent results on zodiacal light are used to show that optics, dynamics, and infrared must be considered together to properly and fully characterize the interplanetary dust complex.
The Interplanetary Micrometeoroid Flux and Lunar Primary and Secondary Microcraters
Authors: Zook H.A. , Lange G. , Grün E. , Fechtig H.
Published: July 2016

We are gaining an increased awareness and understanding of Earth-orbiting space debris. Meteoroid experiments in near-Earth orbit must therefore now be able to differentiate between interplanetary meteoroids and space debris. Space debris impacts are not thought, however, to have significantly affected near-Earth meteoroid measurements carried out in the early 1960’s. New experimental evidence also makes it appear very probable that most impact pits on lunar rocks with pit diameters smaller than 7 micrometers have been generated by lunar secondary ejecta impacts, and not by primary meteoroid impacts. In addition, ages determined from solar flare tracks in lunar rocks are not considered secure. Lunar crater production rates are more reliably deduced from meteoroid space experiments and not from solar flare track ages. When all of the above qualifications are taken into account, however, a rather satisfactorily self-consistent meteoroid flux versus mass distribution is obtained.
Optical Properties of Rough Grains: A Theoretical Study
Authors: Perrin J.M. , Lamy L.
Published: July 2016

Recent work on the light scattering by large rough particles has led us to propose a model based on the high-energy approximation, the laws of geometrical optics and a mathematical description of the properties of the particle roughness. The influence of the various parameters of the model including those characterizing the roughness on the total intensity and the polarization is presented.
The Optical Properties of Circumstellar and Interstellar Dust in the Mid-IR
Authors: Pegourie B. , Papoular R.
Published: July 2016

We deduce the optical efficiency Q (λ)/ a of the circumstellar dust material over the range 8-30 μm from twelve M and G giants and supergiants and that of the dust present in the general ISM and molecular clouds from thirteen protostars. We then discuss the differences between these two profiles in the light of the condensation theory.
On the Dynamic Behaviour of Dust Striae Observed in Comets West 1976VI, and Mrkos 1957V
Authors: Kimura H. , Liu C.-P. , Jockers K.
Published: July 2016

The dynamic properties of the dust striae, observed in comets West 1976VI, and Mrkos 1957V, are reexamined in terms of the high speed emission model (HS model) proposed by Notni (1966). It is demonstrated that most striae can be well fitted to modified synchrones but this kind of fitting does not lead to a conclusive model; in most cases, the dynamic solution is not unique, and, furthermore, the derived high values of the ejection speed appear to be unrealistic, particularly for distant (or old) striae. The results suggest that the required initial velocity could be better interpreted as indicating the presence of nonradial acceleration.
Mass Input into and Output from the Meteoritic Complex
Authors: Grün E. , Zook H.A. , Fechtig H. , Giese R.H.
Published: July 2016

Direct observations have established the size distribution of interplanetary meteoroids at 1 AU as well as the dependence of the spatial density with respect to the distance from the sun. After evaluating the consequences of mutual collisions and the effect of radiation pressure the following conclusions can be drawn: 1. Catastrophic collisions dominate the lifetimes of meteoroids with masses m ≳ 10−5g. About 10 tons per second are lost within 1 AU (mostly in form of 10−4g to 10−1g particles). Under steady state conditions these meteor sized particles have to be replenished by other sources, e.g. comets. 2. After being crushed by collisions 70 to 85% of this mass will be in form of particles with masses 10−10g ≲ m ≲ 10−5g. Part of these “zodiacal light” particles (about 0.3 tons per second) are transported by the Poynting Robertson effect towards the sun where they will evaporate. However, since the collisional production of these intermediate sized particles exceeds their losses this population is presently not in equilibrium. 3. 15 to 30% of the collisional fragments have masses m ≲ 10−10 g. Most of these small particles will be injected into hyperbolic orbits by radiation pressure (β-meteoroids).
Lorentz Scattering of Interplanetary Dust Grains
Authors: Barge P. , Pellat R. , Millet J.
Published: July 2016

The scattering of dust grains orbits due to recurrent sectors of the interplanetary magnetic field is reinvestigated with a better formalism. Our method reveals the resonant character of the diffusion and is well suited for the problem. The spreads in the orbital parameters are found less important than believed untill now and to vary rapidly with eccentricity and semi-major axis. Only the small dielectric grains with size less than 0.5 μm may be scattered by the Lorentz force fluctuations; the main diffusion occurs in inclination and near the sun (20-60 R⊙).
Objective Grating Soft X-Ray Spectroscopy of Compact Binary X-Ray Sources
Authors: Kahn S.M. , Vrtilek S.D. , Chiappetti L. , White N.E.
Published: July 2016

The presence of objective transmission gratings on the two recent X-ray telescope experiments, the Einstein and EXOSAT Observatories, has opened up a new avenue of research in X-ray astronomy by enabling us, for the first time, to obtain moderate-to-high resolution spectra of cosmic sources in the soft X-ray band (λ ~ 5–200 Å). Both experiments incorporated gold bar transmission gratings with line densities of 500 1/mm and 1000 1/mm which could be inserted into the X-ray optical path at the exit from a grazing incidence mirror. At short wavelengths, the resolution was determined principally by the spatial resolution of the detector-telescope combination. For Einstein, this was Δλ ~ 0.4 Å for the 1000 1/mm grating and ~ 0.8 Å for the 500 1/mm grating. For EXOSAT, the resolution was somewhat worse: Δλ ~ 1.5 Å for the 1000 1/mm grating, and ~ 3 Å for the 500 1/mm grating. (More complete descriptions of these instruments can be found in Seward et al. 1982 and de Korte et al. 1981.)
New Results of the Unresolved Transition Arrays Method
Authors: Klapisch M. , Krasnitz A. , Mandelbaum P. , Bauche-Arnoult C. , Bauche J.
Published: July 2016

The formulas for mean wavelengths and widths of Unresolved Transition Arrays (UTA)[1,2], have been extended to include spectator electrons and jj transitions. These were used to interpret several sorts of satellite spectra, e.g., 3d10 nℓq− −3d94fnq transitions in atoms Tm thru W from laser produced plasmas, and 3dm4s − 3dm−1 4p4s in Mo and Pd spectra. The Unresolved Character of the UTA will be discussed thanks to an evaluation of the number of lines in the array. This will be applied to 4d-4f transitions in Ionized Rare Earths.
Determination of Absolute X-Ray Wavelength with the Double Reflection Method
Authors: Fraenkel Benjamin S.
Published: July 2016

It has been shown that is is possible to determine absolute wavelength values of X-ray radiation emitted as a result of electron transitions in ions or atoms, without precise Spectrometers and without reference “lines”. Knowledge of the lattice constants of the diffracting crystal is sufficient for the determination of the wavelengths. Here the first experiment describing the feasibility of the method is shown.

Usually spectra are obtained in form of “lines”. In the X-ray case, however, it is possible to obtain spectra in form of points, ordered along lines. The lines represent the white radiation [Fig. 1].
Time-Resolved Spectra in the 5–330 Å Region Emitted from the PLT and TFTR Tokamak Plasmas
Authors: Schwob J.L. , Wouters A.W. , Suckewer S. , Boody F.P. , Finkenthal M.
Published: July 2016

The analysis of impurity radiation from Tokamak plasmas is one of the most important diagnostics, allowing the measurement of the impurity concentrations, radiation losses and particle transport studies. This study requires simultaneous time-resolved observation of spectral lines from many ionization states for each element. The most intense and important lines are the He and H-like resonance transitions of Oxygen and Carbon and Δn = 0, 1 transitions of highly ionized metallic impurities. These emmissions have been recorded on PLT and TFTR tokamaks by means of a soft X-ray multichannel spectrometer (SOXMOS).
Inverse Inelastic Scattering Theory
Authors: Chuan Cao xuan
Published: July 2016

For inverse scattering theories, it is well known that in order to guarrantee the existence and uniquness of the solution, drastic restrictions must be imposed on the scattering potential or on the scattering data collected from experiments (see for example Newton 1966). The existing theories in their original form such as the Geldfan Levitan or the Marehenko equations therefore cannot be used in a straightforward manner and some further steps toward simplifications have to be considered.

In inelastic scattering problems where many coupled channels must be taken into account to construct various elements of the scattering matrix the problem become much more complicated both from the theoretical and experimental point of view. The present work deal only with the energy fixed case and show that a solution can nevertheless be obtained by using on one hand the conventional technique of the Abelian transformation which has been extensively applied in the JWKB approach to the one channel problem (see for example a general review by Buck 1971) with on the other some results obtained recently concerning a system of coupled differential equations (Cao 1982 1).
Transitions of the Type 2s–2p in Highly–Ionized Cu Through Rb
Authors: Behring W.E. , Cohen L. , Seely J.F. , Feldman U. , Goldsmith Samuel , Richardson M.
Published: July 2016

We report here the observation of spectral lines in the F I, 0 I, N I, and C I isoelectronic sequences of Cu, Zn, Ga, Ge, As, Se, Br, and Rb. The plasma was produced by the spherical irradiation of solid targets using six frequency-tripled beams from the OMEGA laser system at the University of Rochester. The wavelengths were recorded using a 3 meter grazing incidence spectrograph, and the wavelengths were determined relative to several previously observed lines in the F I, 0 I, and Na I sequences. There is good overall consistency with the wavelengths recommended by Edlen (1983) for the F I and O I sequences and with the wavelengths measured by Kononov (1979) for the Na I sequence. Most of the observed transitions in the N I and C I sequences represent new identifications, and a complete set of energies for the 2s2p4 configuration of the N-like ions Cu XXIII, Zn XXIV, Ga XXV, and Ge XXVI is presented.
Introduction and Overview
Authors: Mihalas Dimitri
Published: July 2016

The theme of this Colloquium is radiation hydrodynamics in and around stars and other compact bodies. To open our discussions, I would like to offer some rather elementary remarks about the role played by radiation in astrophysics.

It is probably true that most astronomers view radiation primarily as a diagnostic tool. After all, the only access we have to astrophysical bodies (with a few exceptions inside the Solar System) is the photons we capture from them. And so an immense effort has been devoted to the development of techniques for converting raw information about the spatial, temporal, spectral, and polarization variation of the observed radiation field into knowledge about the physical structure of the object that produced the radiation. There are many difficult challenges, both observational and theoretical, to be met in this process, and the field is in a state of rapid development today, and will remain so for the forseeable future. Nevertheless, in the context of this conference it is worth emphasizing that in the diagnostic problem radiation plays an essentially passive role; it is merely the tool used to analyze the situation.
Jets From Young Stars
Authors: Mundt Reinhard
Published: July 2016

Recent optical observations have shown that many young stars are capable of generating highly-collimated bipolar flows. Such flows are evident from narrow emission-line jets extending over 0.01-1 pc and having opening angles of a few degrees. Their measured radial velocities reach values of up to 400 km/s. For most known jets the “driving stars” are T Tauri stars or IR-sources of low to moderate luminosity (1-100 L⊙) . The typical velocities, Mach numbers, particle densities, and mass fluxes of these jets are estimated to be 200-400 km/s, 10-40, 15-150 cm−3, and 10−10−10−7 M⊙/yr, respectively. The estimated mass fluxes and velocities are consistent with our present knowledge of T Tauri star wind properties.

The emission-line spectra of the jets are the same as observed in Herbig-Haro (HH) objects. Furthermore, the brightest parts of some jets (hot spots) are known as HH objects, having often been discovered many years before their associated jet. Thus, both phenomena are highly related and in both cases the emission lines are very probably formed in the cooling regions of shock waves with velocities of 50-100 km/s. There are a variety of mechanisms, which can in principal excite internal (oblique) Shockwaves in these jets. Examples of likely excitation mechanisms are fluid dynamical instabilities or pressure gradients in the ambient medium.

A model is proposed in which HH objects are representing the locations of the most strongly radiating (internal)shock waves in these jets. For those HH objects being located at the end of the jet the observational data strongly suggest that they are tracing the working surface of the jet. This idea is consistent with the observed proper motions of these HH objects, the typical densities near the edges of their associated molecular clouds, and with the jet parameter given above. For a more detailed discussion of these jets the reader is refered to the review articles listed below.
Theory of Stellar and Extragalactic Jets
Authors: Blandford R.D.
Published: July 2016

Different types of astrophysical jets are briefly described and the wide differences in their observed properties are emphasized. Various physical mechanisms that have been proposed for creating jets, based on gas dynamical, magnetic, and radiative stresses are briefly reviewed. It is argued that magnetic fields are probably generally important for collimating astrophysical jets.
The Use of History in the Teaching of Astronomy
Authors: Gingerich Owen
Published: July 2016

Three good reasons for using historical materials in teaching astronomy are:

• The simplest concepts are introduced first in a natural sequence;

• For non-science students, history can build onto other interests;

• The historical perspective shows the changing and iterative nature of scientific explanatory structures.
Teaching Human Culture Through Astronomy
Authors: Nikolov N.S.
Published: July 2016

One of the phenomena in the development of science in the second half of the twentieth century is the appearance of complex branches of knowledge. This fact along with the accelerated increase of science information called forth well-known integrative processes in education. One of the most widely spread forms of these processes is the incorporation of one school subject in another. In such a way, astronomy in secondary school is incorporated in the subject of physics and sometimes in geography and mathematics. The argument for this, if there exists one, is that nowadays astronomy is astrophysics, i.e., physics of celestial bodies, or that the cosmographical function of astronomy resembles the function of geography.

In this paper, we make an attempt to adhere to the thesis that astronomy is a school subject with wider connections in the human sphere than with only one branch of science (Nikolov, 1986). As a consequence, if the school subject astronomy is incorporated only in a specific discipline, this would limit the possibility of teaching facts or phenomena of other spheres of the human spirit.
The Northern Lights as an Introduction to the Universe
Authors: Solheim J.E.
Published: July 2016

The University of Tromsø is located at 70° northern latitude. It is planned for 3,000 students and was opened in 1972. Research interests in physics are centered on the physics related to the upper atmosphere. The region is coastal and mountainous, and is sparsely inhabited. People in the region are good observers, and those away from city lights watch the lively auroral displays that can be observed almost every clear, dark night. The different auroral forms — wavering structure, colors, and diffusing and changing appearance — all challenge the imagination. There are popular and folkloric descriptions as well as manifestations in art, including poetry, paintings, music, and drama.
Innovations in Astronomy at the Open University
Authors: Jones Barrie W.
Published: July 2016

Dreary correspondence colleges that send tatty typewritten notes to their suffering students are gradually being eclipsed by full-fledged open-learning institutions of wide educational significance. The Open University is the premier open-learning institution in the U.K., perhaps even in the world. It already offers an astronomy course as a significant part of a science major degree, and further courses are planned, including an in-service course for school teachers.

In this article I discuss:

1. open learning systems, including the ways in which various educational media can be used to good effect

2. some features of the existing astronomy course of The Open University, and some possibilities for future courses.
Maximizing the Educational Value of Student Research Participation
Authors: Belserene Emilia Pisani
Published: July 2016

The Maria Mitchell Observatory monitors variable stars photographically and has lately begun to receive photometric data remotely. The staff consists solely of the director and undergraduate student assistants during summer and January vacations. Research topics are chosen for both their scientific interest and their educational potential.

The scientific goal is to improve variable-star statistics by answering any unresolved observational questions. Lately the emphasis is on pulsators in the Cepheid instability strip. Can we watch the stars grow older? We look for deviations from a single, constant period.
An Application of Personal Computers in Astronomy Education
Authors: Nikolov A.S.
Published: July 2016

Observations play an important role in the process of teaching astronomical knowledge. Practical observations of astronomical phenomena lead to analysis and explanation based on natural laws and so form the basis of cognitive processes in the education. Evidently the observations are an integral part of acquiring astronomical knowledge. Giving up observations, no matter what the reasons, is equivalent to losing quality in the educational process. It decreases the possible influence over the personal development of pupils and students. At the same time, observation and observational results are important for success in education.

Carefully planned observational time has a substantial influence on cognitive and educational processes. It leads to considerably more active participation in astronomy lectures.
The Paperless Astronomy Classroom
Authors: LoPresto James C.
Published: July 2016

The “Paperless Astronomy Classroom” was instituted at Edinboro University of Pennsylvania in the fall semester of the 1985–1986 academic year.

The goal of this endeavor was to teach an elementary and some advanced astronomy courses “on line” with the use of multiple terminals supported by a Digital VAX 11/785. Currently the system used is a clustered VAX system using two VAX 11/785’s and one VAX 8550.

The procedure of the “paperless classroom” eliminates the need for the transfer of paper between professor and students (homework, exams, supplementary handouts) in the first phase and eliminates the need for a textbook in the second phase.

An equally important goal is to provide additional enhancement for the student that may not be convenient or easily available from a textbook and the traditional classroom. Such an enhancement is series of large data bases, some of which can be the small data bases that traditionally appear in the appendices of textbooks. Another example might be a data base of graphs and charts (e.g., H-R diagrams, periodic table, abundance tables and graphs, binding energy curves, etc.).
Textbook Panel Presentation — IAU Colloquium 105
Authors: Robbins R. Robert
Published: July 2016

You might be somewhat surprised by the presentations [as delivered] so far, in that there has been relatively little discussion of pedagogical matters (e.g., what should be the content of a text and what should be its order and manner of presentation). It seems that rather personal factors are in the foreground of everyone’s thinking. But I think that is probably inevitable, because the process of writing a textbook is not only a huge undertaking that comes to dominate the life of the author, but it is also an endeavor that places the author directly at the interface between the idealistic world of education and the very practical world of economics as dictated by the realities of the publishing markets. In addition, a textbook has a strong effect on an astronomy class. It has been suggested that an important reason why so many educational research studies fail to come to a definite conclusion is that the textbook is such a dominant influence that it swamps all the other factors!
IAU Commission 46: Astronomy Educational Material
Authors: Gerbaldi M.
Published: July 2016

During the IAU Assembly in Prague (1967), Commission 46 on the Teaching of Astronomy decided to prepare a world-wide list of available material suitable for astronomy education at various levels and as in many languages as possible.

The first list was published in 1970 by E. Müller, under the title: “Astronomy Educational Material.” Since then, in order to keep the list up to date, an “Addendum” has been edited every three years.

Each Addendum is subdivided into three parts:

part A: material in the English language

part B: material in Slavic languages

part C: material in all languages with the exception of English and Slavic.
The Training of Pre-College Teachers through Workshops in Astronomy
Authors: Hemenway Mary Kay
Published: July 2016

Most pre-college teachers in the United States have not been trained in astronomy. In Texas, astronomical concepts enter the pre-college science curriculum at all levels.

During the last six years, I have presented two different types of workshops: intensive three-week summer institutes for rather small numbers of teachers, and shorter 6- to 18-hour workshops for larger groups.

The University of Texas Astronomy Department and McDonald Observatory have hosted five of the intensive institutes. The institutes were established to offer an opportunity to learn astronomy through hands-on activities (Texas education regulations mandate that 40 per cent of all pre-college science classes should be laboratory oriented), and to introduce the teachers to modern astronomical research and facilities.
The Teaching of Astronomy at the Unità Di Ricerca Asiago
Authors: Abati Laura Erculiani
Published: July 2016

The Unità di Ricerca (U.d.R.) Asiago, of the National Astronomical Group of the Italian Research Council, consists of:

1) the staff of the Padua-Asiago Observatory

2) the staff of the Astronomy Department of Padua University

3) external members with interests in stellar, galactic, and extragalactic astronomy and in technology.

The teaching of astronomy at the U.d.R. Asiago has several aspects: popularization, educational visits, cooperation with amateur groups, promotional contacts with public institutions, participation in a commission on school programs, and participation in the educational activities of the Italian Astronomical Society.
Philosophy and Directions in Planetarium Programming
Authors: Clarke T.R.
Published: July 2016

I am going to start with the premise that planetariums serve several roles in their communities:

1. They are popularizers of astronomy and space science

2. They support and enhance the teaching of astronomy and related subjects within the formal education system

3. They provide a community resource for astronomical information

Not all planetariums incorporate all of these roles or do so to the same degree.

Planetariums, as facilities, come in a variety of forms. At one extreme might be a space theater with its wide-format films. A major public facility would have a strong emphasis on public shows and school programming. A college or school facility would emphasize programming for the education system at some or all levels with some or no public programs. At the other extreme would be the small portable planetariums with 100 per cent use for school activities.
The Past and Present State of Astronomy Education in Thailand
Authors: Vanichai Yupa
Published: July 2016

About 300 years ago in Lopburi and Ayudhaya, many astronomical observatories were designed, constructed, and supported by the Roman Catholic missionaries from Europe and by King Narai the Great of Siam (Thailand). The interesting recorded history of Thai astronomy was found in the national museum of France a few years ago. Afterwards, the ruined observatories were searched for and found. A tercentennial commemorative ceremony of Thai astronomy was held on April 30, 1988.

The French emissary and the Roman Catholic missionaries in the reign of King Louis XIV first visited Thailand in 1685. Besides intending to spread the Catholic religion, they carried out research on surveying local and celestial positions. A Thai royal astrologer calculated and predicted a total lunar eclipse on December 11, 1685. King Narai, together with the missionaries, observed the eclipse at Lopburi through a telescope having magnification of 30 to 72. A partial solar eclipse was also observed near the same place on April 30, 1688. Sanpaolo, a Catholic church on the outskirts of Lopburi, was the site of the first astronomical observatory in Thailand, built in 1685. Another observatory in Lopburi, built in the house of a Persian emissary, later became a Thai temple. Other astronomical observatories were supposedly built in Ayudhaya, the capital of Thailand in King Narai’s period, and should be worthy of search and restoration. However, the historical events on record have not yet been clearly found out.
Surplus Texts and Journals for Abroad — a Canadian Program
Authors: Batten Alan H. , Brückner Dieter W.
Published: July 2016

We wish to report briefly on a program for sending donated astronomical books and journals to overseas institutions that have not been able to acquire them in other ways. The program is being sponsored for a trial year by the Canadian Astronomical Society (CASCA), in co-operation with the Canadian Organization for Development through Education (CODE), which has generously offered to pay for the shipments to some countries, mostly in Africa and the Caribbean.

We have been soliciting donations from among the membership of CASCA for materials surplus to their needs, and have offered these through the Newsletter of IAU Commission 46, the IAU Bulletin, and Colloquium 105. Our efforts have been successful, and at the time of writing, about half the journal runs and texts, and almost all of the monographs available at the time of the Colloquium have found recipients. We are gratified by this result, as we had been unsure of the usefulness of what we were doing. Discussions at the Colloquium have given us additional reassurance in this regard.
Accretion Disks in Algols
Authors: Smak J.
Published: July 2016

Basic theoretical concepts concerning formation and properties of disKs in close binary systems are reviewed and compared with observations of Algols.
The Utrecht Photometric System (≡ UPS) and Some Results With it
Authors: Heintze J.R.W.
Published: July 2016

The Utrecht Photometric System (≡ UPS) is a narrow-band photometric system (Δλ ⩽ 10 nm) characterized by wavelength regions in which no telluric lines and nearly no stellar/interstellar spectral lines are present. Because in the near-infra red the density of spectral lines is much less than in the visible and blue, filters with transmission as far as possible into the near-infra red are necessary. Photomultipliers with GaAs cathodes, which have a high sensitivity up to 900 nm have enabled the design of the UPS. In Figure 1 the absolute

Figure 1. Comparison of responsivities of several cathodes.

Figure 2. The positions of the UPS filters with respect to solar and telluric lines.

responsivity of the GaAs cathode is compared with S1, S4, S13, S20 and S20 extended cathodes. In Figure 2a the transmission curves of the UPS (474, 579, 672, 781 and 871 nm) are given as a function of wavelength (Provoost (1980) gives larger graphs for the transmissions). Figure 2b shows in the lower part over 20 Å summed up equivalent widths of solar lines as a function of wavelength. In the upper part of Figure 2b the same is done for the telluric lines.