bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theory of Stellar and Extragalactic Jets
Authors: Blandford R.D. 
Published: July 2016

AbstractDifferent 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.
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.
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 effect2. 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.).
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 languagepart B: material in Slavic languagespart 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 Observatory2) the staff of the Astronomy Department of Padua University3) 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 science2. They support and enhance the teaching of astronomy and related subjects within the formal education system3. They provide a community resource for astronomical informationNot 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.
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 absoluteFigure 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.
U Cephei Revisited
Authors: Nelson Burt , Davis Walter D. 
Published: July 2016

Observations of U Cephei made by C. M. Huffer, et al, in 1950-51 and in 1959, are presented here to contrast with other observations made by Huffer and others.In many cases, to see a light-curve of an eclipsing binary is to see all light-curves for that particular system. This is certainly not true of U Cephei which, because of its rapid variations, has held the attention of so many for so long.The 1950-51 yellow and blue observations were made at Washburn Observatory, Madison. The data have been transcribed from Huffer’s note books to a floppy disk and are available.
A New Model for Algol (β Persei)
Authors: Richards Mercedes T. , Bolton C. T. , Mochnacki S. W. 
Published: July 2016

We studied the circumstellar gas in Algol (β Persei) by analysing Hαdifference profiles (observed profiles minus composite theoretical (LTE) photospheric absorption line profiles of the stars), at 98 phases in the binary’s orbit (cf. Richards 1986, Ph.D. thesis, University of Toronto). The data were obtained from Sept. 1976 to Dec. 1977; with an average phase interval of 0.02 over the entire orbit.There was a smooth change in the profiles from strong, redshifted emission just outside primary eclipse, to an almost flat profile at mid-secondary eclipse, to strong, blueshifted emission just before primary eclipse began. Absorption was detected throughout primary eclipse, and there were smooth transitions between pure absorption and pure emission. The emission and absorption had FWHM’s of ~200 km s−1 and ~200 to 450 km s−1, respectively; with line strengths up to 10% and 19% of the continuum, respectively.
CCD spectroscopy of the W Serpentis binaries KX And and RX Cas
Authors: Schneider H. , Pavlovski K. 
Published: July 2016

AbstractInitial results are presented from a study of Hγ profiles in the two interacting binaries KX And and RX Cas of W Serpentis type. The used CCD spectra with a resolution of 0.13Å/px were obtained with the 2.2m telescope and the Coudé spectrograph at the German-Spanish Astronomical Center at Calar Alto/Spain.
Symbiotic Stars
Authors: Allen David A. 
Published: July 2016

AbstractI review our current knowledge of symbiotic stars. A great many papers have graced the literature in the fifty years of their study, and many data are available on the spectral variations at optical wavelengths these stars undergo. I do not give extensive references to those data, for previous reviews have done so quite adequately. Rather, I concentrate on the extensive widening of the wavebands within which symbiotic stars have been studied over the past few years, and attempt to synthesise the data into a coherent picture.Symbiotic stars are most readily explained as interacting binaries, though single star models may still be tenable for some systems. They are made much more complex than most other interacting binaries by the variety of accreting stars, and because gas flows may be highly structured. Moreover, their study is more difficult than that of dwarf novae because the orbital periods are long compared to the activity cycles of the accretion phenomena.Our data base has expanded enormously with our present spectral Catholicism. But there remains much valuable work to be done with even simple equipment on small telescopes. I suggest in a final section areas for future work.
Observations of Binaries and Evolutionary Implications
Authors: De Loore C. 
Published: July 2016

AbstractComparison of the characteristics of groups of stars in various evolutionary phases and the study of individual systems allow to make estimates of the parameters governing mass loss and mass transfer. Observations enable us in a few cases to determine geometric models for binaries during or after the mass transfer phase (disks, rings, common envelopes, symbiotics, interacting binaries, compact components).From spectra taken at different phases, radial velocity curves can be derived and masses and radii can be determined. In special cases spectra in different spectral ranges (visual, UV, X-ray) are required for the determination of the radial velocities of the two components (for X-ray binaries, for systems with hot and cool components). Information on parameters related to the mass transfer process enables us to consider non conservative evolution - i.e. the computation of evolutionary sequences with the assumption that mass and angular momentum not only are transferred from one of the components towards the other one, but that also mass and angular momentum can leave the system. Careful and detailed analysis of the observations allows in certain cases to determine the parameters governing this mass and angular momentum loss, and for contact phases, to determine the degree of contact.
Mass Loss in Semi-Detached Binaries
Authors: Abhyankar K. D. 
Published: July 2016

AbstractPre-Main-Sequence contracting objects, post-Main-Sequence expanding stars and mass-losing components of semi-detached systems all occupy more or less the same region in the conventional H-R-diagram. We make a transformation to variables Δ (logL) and Δ (log Te), where Δ is the difference between the observed quantity, log L or log Te, and the value of that quantity which a star of the same mass would have on the empirical Main Sequence. It is demonstrated that a plot between the new variables clearly separates the mass-losing stars from other objects which is essentially an effect of the increasing abundance of helium relative to hydrogen.
Constraints for Cataclysmic Binary Evolution as Derived from Space Distributions
Authors: Duerbeck H. W. 
Published: July 2016

AbstractSpace densities and galactic z-distributions of novae, recurrent novae, dwarf novae and symbiotic stars are newly determined and discussed in the context of earlier determinations. The data are then compared with the distributions of single and binary stars of possibly related types (late type giants, Mira variables, Algol systems, W UMa systems).Novae and dwarf novae have similar distributions, those of fairly young stellar populations. The observed space density of potential novae (novalike objects) indicates that the mean recurrence time of novae might be as small as a few hundred years, which leads, with given nova shell masses and mass transfer rates in the minimum stage, to a secular decrease of the masses of the components undergoing nova outbursts.Recurrent novae and symbiotic stars have distributions of older stellar populations, similar to those of late type giants and Mira variables.On the basis of galactic distribution, novae and dwarf novae are closely related and may be final stages of W UMa systems, as well as progenitors of supernovae of type I. A small fraction of W UMa systems seems to belong to an older population. If evolutionary transitions between these types of stars can be substantiated, the presence of a minority of novae and dwarf novae in globular clusters and of supernovae I in elliptical galaxies can be explained.Due to the lack of sufficiently well determined space distributions of Algol binaries, the suggestion that long-period Algol systems might be the progenitors of cataclysmic binaries can as yet neither be substantiated nor refuted. A very high space density of long-period Algol systems in the solar neighbourhood is derived. The observed space density of cataclysmic binaries could be explained by the transformation of a small percentage of the long-period Algol systems by common envelope evolution.
Physical Studies of Asteroids By Polarization of the Light
Authors: Dollfus Audouin 
Published: July 2016

Curves of polarization are available at present for asteroids Vesta, Ceres, Pallas, Iris, Flora, and Icarus. These curves are compared with those of the satellites of Jupiter and Mercury, the Moon, and Mars. Laboratory simulations had already proved that the Moon's surface behaves like a powder of pulverized basalts; the recent confirmation by direct exploration is proving the significance of the method for remote determination of the surface properties of celestial bodies. The simulation of the Martian surface is found on small grained powders oxidized by ferreous limonite or goethite. New laboratory measurements were conducted to prepare the simulation of the asteroidal surfaces. Samples of the lunar surface returned to Earth provide impact-generated regolith and bare rocks superficially pitted and etched by impacts of the types suggested to be found on asteroidal surfaces; they were analyzed polarimetrically.Preliminary interpretations show that Vesta departs significantly from the other asteroids and cannot be covered by frost deposits or by aggregate cosmic dusts; a regolith-type surface generated by impacts or a coating of cohesive grains is indicated.Ceres, Pallas, and Iris are darker, and their polarizations do not suggest a pure regolithic surface, but cohesive grains or aggregates of dust are indicated.Icarus is 108 times smaller in mass; its polarization authorizes a fluffy, loosely aggregated dust deposit; however, a cometary model with stones embedded in ice is perhaps not ruled out on the basis of the present data.The way in which deep-space missions near the asteroidal belt can improve these results is discussed.
Asteroidal Theories and Experiments
Authors: Arrhenius Gustaf , Alfvén Hannes 
Published: July 2016

Theories on the origin and evolution of asteroids are confronted with three types of experimental tests. The first refers to the dynamic state of the asteroids and consists of orbital and in some cases spin data for bodies as small as about 1 km. (There are reasons to assume that the size spectrum extends to very small objects but nothing is known about them.)The second type consists of observations of the chemical and structural properties of objects fallen to Earth from space. Here the relationship to asteroids is much more tenuous. Nevertheless, the study of meteorites has provided important insight into the chemical evolution of small bodies in space. As long as one realizes that such data refer only to bodies of special structure, composition, velocity, and other orbital characteristics, they can be useful also for conjectures about asteroids.
A Core-Mantle Model for Cometary Nuclei and Asteroids of Possible Cometary Origin
Authors: Sekanina Zdenek 
Published: July 2016

Arguments for a long time have been brought forward in support of the idea that the minor planets with orbits approaching Earth's orbit might be of cometary origin. Our feeling is that before such hypotheses are considered for any particular object, it is necessary to prove that differences in physical appearance and dynamical behavior between a typical asteroid of the Apollo or Albert types and a typical short-period comet can be interpreted in terms of cometary evolution.In this paper, we discuss models of cometary nuclei, transition of an object from cometary phase into asteroidal phase, and specific asteroidal objects that may be of cometary origin.