bluuebunny/crossref_metadata_2025 huggingface dataset:
Theory of Protostellar Objects
Authors: Shu Frank H.
Published: July 2016

Many problems in the theory of star formation are amenable to a complementary attack in which the analytical approach is used to reduce the governing equations to a form amenable to efficient numerical solution. This strategy has proven very useful in helping to resolve several astrophysical puzzles which arise because the bulk of star formation today is observed to occur, with relatively low efficiency, in giant molecular cloud complexes. How does a cloud of 105-106M⊙ know how to form stars of mass ~ 1 M⊙? How does the interstellar medium know, to one or two orders of magnitude, that roughly hydrogen atoms of mass mH are needed to yield thermonuclear fusion in a self-gravitating ball of gas? Why have radio astronomers not detected unambiguous evidence for the collapse motions attendant to star formation? Why has a true protostar, the “holy grail” of infrared astronomy, been so hard to find? Why do young stellar objects almost universally exhibit powerful outflows? Why is the geometry for these outflows often bipolar? Why do T Tauri stars have such active chromospheres? In this review we suggest that these puzzles all have a related resolution, in the nature of how gravitational collapse is initiated and terminated in the slowly rotating cores of molecular clouds.
Radiation Hydrodynamics in Solar Flares
Authors: Fisher George H.
Published: July 2016

Solar flares are currently understood as the explosive release of energy stored in the form of stressed magnetic fields. In many cases, the released energy seems to take the form of large numbers of electrons accelerated to high energies (the nonthermal electron “thick target” model), or alternatively plasma heated to very high temperatures behind a rapidly moving conduction front (the “thermal” model). The transport of this energy into the remaining portion of the atmosphere results in violent mass motion and strong emission across the electromagnetic spectrum. Radiation processes play a crucial role in determining the ensuing plasma motion.

One important phenomenon observed during flares is the appearance in coronal magnetic loops of large amounts of upflowing, soft X-ray emitting plasma at temperatures of 1−2×107[K]. It is believed that this is due to chromospheric evaporation, the process of heating cool (T - 104[K]) chromospheric material beyond its ability to radiate. Detailed calculations of thick target heating show that if nonthermal electrons heat the chromosphere directly, then the evaporation process can result in explosive upward motion of X-ray emitting plasma if the heating rate exceeds a threshold value. In such a case, upflow velocities approach an upper limit of roughly 2.35 csas the heating rate is increased beyond the threshold, where csis the sound speed in the evaporated plasma. This is known as explosive evaporation. If the flare heating rate is less than the threshold, evaporation takes place indirectly through thermal conduction of heat deposited in the corona by the energetic electrons. Upflows in this case are roughly 10 to 20% of the upper limit. Evaporation by thermal model heating always takes place through thermal conduction, and the computed upflow speeds seem to be about 10% to 20% of the upper limit, independent of the energy flux.

The pressure increase in the evaporated plasma for either the thick target or thermal model leads to a number of interesting phenomena in the flare chromosphere. The sudden pressure increase initiates a downward moving “chromospheric condensation”, an overdense region which gradually decelerates as it accretes material and propagates into the gravitationally stratified chromosphere. Solutions to an equation of motion for this condensation shows that its motion decays after about one minute of propagation into the chromosphere. When the front of this downflowing region is supersonic relative to the atmosphere ahead of it, a radiating shock will form. If the downflow is rapid enough, the shock strength should be sufficient to excite UV radiation normally associated with the transition region, and furthermore, the radiating shock will be brighter than the transition region. These results lead to a number of observationally testable relationships between the optical and ultraviolet spectra from the condensation and radiating shock.
The Classical Nova Outburst
Authors: Starrfieldt Sumner G.
Published: July 2016

In this review I will present and discuss both the nova outburst and the theoretical calculations related to its cause and evolution. I use the commonly accepted model for a nova: a close binary system with one member a white dwarf and the other member a larger, cooler star that fills its Roche lobe. Because it fills its lobe, any tendency for it to grow in size because of evolutionary processes or for the lobe to shrink because of angular momentum losses will cause a flow of gas through the inner Lagrangian point into the lobe of the white dwarf. The size of the white dwarf is small compared to the size of its lobe and the high angular momentum of the transferred material causes it to spiral into an accretion disk surrounding the white dwarf. Some viscous process, as yet unknown, acts to transfer mass inward and angular momentum outward through the disk so that a fraction of the material lost by the secondary ultimately ends up on the white dwarf. Over a long period of time, the accreted layer will grow in thickness until the bottom reaches a temperature that is high enough to initiate thermonuclear burning of hydrogen by the proton-proton reaction chain. The further evolution of thermonuclear burning on the white dwarf now depends upon the mass and luminosity of the white dwarf, the rate of mass accretion, and the chemical composition of the reacting layer.
Physical Processes in Active Galactic Nuclei
Authors: Svensson Roland
Published: July 2016

Active galactic nuclei (AGNs) emit continuum radiation evenly spread over up to ten decades in frequency from the radio into the gamma-ray range. Plausible emission mechanisms and their characteristics are reviewed. In the deep potential wells around black holes the mean energy per proton can reach 100 MeV. Part or all of this energy may be channeled to all electrons equally (thermal plasma) or, preferentially, into only a small fraction of the electrons (nonthermal plasma). In the former case thermal Comptonization of soft photons may be the dominant emission mechanism, while in the latter case the synchrotron and the inverse Compton scattering process (synchro-self-Compton) are likely to dominate.

When the compactness parameter L (hν≈mc2 )/R. (power L, radius R) exceeds about 1030 ergs cm−1s−1 or L>Lc ≡ 1030R ergs s−1, then electron-positron pair production takes place due to photon-photon interactions causing the source to shroud itself with an electron-positron atmosphere. The efficiency of pair cascades in converting injected energy into electron-positron rest mass can reach levels of about 10% in static pair atmospheres. The emerging radiation is strongly modified by the pair atmosphere causing the spectrum to soften and to have characteristic breaks.

For emission coming from a region near the Schwarzschild radius, L>10-3LEdd is sufficient to cause prolific pair production. Radiation pressure then drives a mildly relativistic pair wind with Compton drag limiting the Lorentz factor to be less then 10. The pair rest mass power is at most of the order of Lc.

Most results so far on static pair atmospheres and pair winds are either qualitative or based on simple analytical models. Needed numerical treatments of both time dependent and steady radiative transfer of both the continuum and the annihilation line radiation in mildly relativistic flows are relevant not only for AGNs but also for gamma ray bursts and galactic black hole sources.
Hydrodynamics Near the Central Engine
Authors: Hawley John F.
Published: July 2016

The “central engine” of quasars and active galactic nuclei Is most likely powered by accretion into a supermassive black hole. A menagerie of steady state accretion flows have been developed, and these are briefly reviewed. Several examples from recent numerical calculations of axisymmetric accretion flows provide disk formation scenarios from which one can calculate plasma densities, and other values of interest for a range of accretion rates and black hole masses. These results can be compared with the well studied, but physically unrealistic case of radial accretion. Although a reasonable conceptual picture of the central engine has been developed, considerable work remains to be done.
Radiation Hydrodynamics: Conference Themes and Unsolved Problems
Authors: Shull J. Michael
Published: July 2016

This paper will be a short review of the topics covered at this conference on “Radiation Hydrodynamics in Stars and Compact Objects.” Rather than attempt to cover all the talks and posters, I will describe what I saw as the main themes and then summarize selected topics that provided unsolved questions. Finally, I will try to decide whether we strayed too far from the original purpose of the meeting. Or, put as a question: Does Radiation Hydrodynamics play a major role in solving a wide range of astrophysical problems?

As described in Mihalas’ introductory talk, radiation can affect an astrophysical plasma, flow, or object in several fashions. First, it can influence the kinematics through ionization, dissociation, and other gas-phase processes that depend on chemistry, ionization state, or excitation. But second, it can influence the dynamics of the flow, through deposition of momentum. Examples of the latter are shock waves, accretion disks, novae, supernovae, and hot-star winds. One can, therefore, divide the topics at this meeting into “active” and “passive” classes of radiation hydrodynamic problems (Table 1). The term “active” implies dynamic pressure from the radiation, whereas the term “passive” allows the radiation to affect the state of the gas, particularly its spectral emissivity, without affecting its motion appreciably.
Astronomy Education in Hungary
Authors: Szécsényi-Nagy Gábor
Published: July 2016

Our educational system, like that of any other country, has grown up to meet the needs of the environment in which it developed. Perhaps its most distinctive feature is its emphasis on education of the masses rather than on education of the intellectuals.

The philosophy of the Hungarian educational system is that a democracy depends upon a well-informed electorate, and that therefore each citizen should receive the best education possible. As a result, in our country most children in the same community attend school together from kindergarten through secondary school practically regardless of differences in intellectual ability or in family background.
The Role of Astronomy in the History of Science
Authors: MacLachlan James
Published: July 2016

This historian of science offers a few samples of the kinds of understandings his students will be subjected to. (a) In early times, Britons used careful observations of astronomical events to establish their calendar; (b) In the 4th century BC, Aristotle used the spheres of Eudoxus to establish his cosmological principles; (c) In the second century of our era, Ptolemy made astronomy scientific, partly for the sake of astrological predictions; (d) In the fifteenth century, Columbus used crude astronomical observations to find latitude, (e) In the sixteenth century, Copernicus revised Ptolemaic astronomy in order to improve its fit with Aristotelian cosmology, and in the process challenged that cosmology; (f) Kepler used Tycho’s more precise data to destroy heavenly circularity; (g) In the early seventeenth century, Galileo based his renovation of motion studies on the investigative style he learned from Ptolemy, coupled with mathematics learned from Euclid and Archimedes.
Interdisciplinary Approaches to Astronomy
Authors: Fraknoi Andrew
Published: July 2016

To understand the motivation for my talk, you must bear in mind what Don Wentzel discussed so eloquently at the beginning of the colloquium. In the U.S., the vast majority of students taking astronomy classes at the college level are not science majors. Many students coming into the astronomy courses are afraid and distrustful of science and often see science as a very alien endeavor, quite separate from their everyday lives and other studies.

For such students, it can sometimes be very reassuring and enlightening to show some interesting connections between astronomy and other (nonscience) fields at a few places in the introductory astronomy course. For example, many students are surprised and excited to see the inspiration that astronomy has provided for music, literature, and art and some of the interesting connections between astronomy and psychology, archaeology, and law.
Planets, Pulsars, And Poetry
Authors: Yorka S.B.
Published: July 2016

For many of us in the United States, the majority of our students are in descriptive astronomy classes. And since these classes typically satisfy general education or core curriculum requirements that must be completed by all students, the students can range from those genuinely interested in astronomy to those who are taking the class because “it sounded less boring” than other options available. Whichever end of that spectrum the students occupy, many of them approach astronomy with quite a bit of anxiety because it is a science class. In student lore, a science class is a class that is by definition more difficult — perhaps verging on the impossible — than other classes, one that discusses totally foreign things in an arcane language and, above all, is a class that has no connection with anything else in the curriculum, except maybe another science class.
Astronomy as a Liberal Art
Authors: Dennis Tom R.
Published: July 2016

Every year in the United States, many thousands of university and college students take a one-semester course in astronomy as part of a “Liberal Arts” curriculum. At many institutions these courses are the raison d’etre for the astronomy program, and at most other institutions they are viewed as an important term in calculating an astronomy department’s contribution.

I have often had a sense that what we are doing in these courses is counter-productive to any serious understanding of the goals of liberal arts curriculum. Over the last six or seven years, as I have been participating in my college’s efforts to introduce a year-long, interdisciplinary survey of the humanities into our curriculum, this hunch has been confirmed: in our efforts to fit astronomy into the liberal-arts curriculum, we have ironically been undermining the enterprise.
The Role of Projects in Astronomy Education
Authors: McNally D.
Published: July 2016

At first sight, there may appear to be a very wide range of project situations that are in use. Students may seem to be doing the equivalent of postgraduate work, or may seem to be working on contract basis, or may even seem to be doing rather long term laboratory exercises, or some mixture of all three. However, there are in essence two major types of project situations — the free-scope project and the set-piece project.

The free-scope project attaches importance to the selection of project topics by the student. The student may be told to select a problem from the entire spectrum of problems offered by the science of astronomy, and to get on with it, or there may be guidelines to restrict the choice. Nevertheless, the choice of topic is the prerogative of the student, and it is believed that the effort of making that choice is important in the teaching/learning process. Because of the range of formats for free-scope projects, it is a convenient form to adapt to meet varying local circumstances.
The Edinburgh Astronomy Teaching and Educational Packages
Authors: Brück M.T. , Tritton S.B.
Published: July 2016

In this paper we describe our experiences with film copies of original astronomical photographs taken with the 1.2-meter U.K. Schmidt Telescope (UKST) in Australia, and used as teaching material in the Department of Astronomy of the University of Edinburgh. Two packages are intended for undergraduate use; the Education Packages are designed as visual aids for colleges, schools, and amateur groups.

The original purpose of the telescope (which was commissioned in 1973) was to carry out a Southern Sky Survey to match the Northern Survey done by the Palomar 48” Schmidt Telescope. The telescope has a very wide field — 6.5 × 6.5 degrees, or equivalent to over a hundred and fifty full moons, and the photographs reach objects of 23rd magnitude: they record stars like the Sun to the very edges of the Galaxy and galaxies to a thousand million light years. Each photograph has an area of 356 × 356 mm and records between 100,000 and 1 million stars and galaxies. The survey photographs are the deepest available maps of the sky and are indispensable tools for astronomers in searches for unusual objects, for investigation of the distribution of galaxies and many other tasks. The UKST is equipped with objective prisms that are capable of producing low dispersion spectra of stars and galaxies. A prism of very small angle is placed in front of the aperture of the telescope so that each individual image is drawn out into a tiny spectrum on the photograph. The dispersion is very small, only a few millimeters from the red to the ultraviolet, but the dominant features in the spectra are recognizable and have many applications.
Using CCD’s in Introductory-Level College Astronomy Laboratories
Authors: Balonek Thomas J.
Published: July 2016

Our university recently purchased a liquid-nitrogen-cooled CCD camera system (from Photometrics Ltd., Tucson, Arizona) which has been installed on our campus’ 40-cm multiple access (Cassegrain/Newtonian) telescope. Images are reduced online at the observatory using Photometrics’ microcomputer-based analysis software package, which includes operations for standard data acquisition and initial stages of data reduction — including corrections for bias, dark current, and flat fielding. Images are displayed on a 256-level-gray-scale black and white monitor. Additional post-processing can be done either on the CCD system’s computer at the observatory or on IBM-AT/PC’s located both at the observatory and in the laboratory.
Teaching Observational Astronomy as a Laboratory Course for Non-Majors
Authors: Kim Yong H.
Published: July 2016

Since antiquity, doing astronomy means basically stepping outside, looking upward, and considering the widest environment. Thus any undergraduate astronomy program, no matter how diverse its course offering, is incomplete without observational astronomy. For example, some California community colleges offer several courses including such titles as “Man and the Cosmos,” “Final Stellar States,” “Astronomy Enrichment,” and “Astronomical Myths, Mysteries & Fallacies,” but do not offer “Observational Astronomy.” As a teaching astronomer, I question the wisdom and honesty of such practice of proliferation solely based on sensationalism. An introductory lecture course and an observational lab course must be the core of lower-division undergraduate astronomy education. Anything else, in my opinion, is peripheral.
Interactive Computer Programs for Teaching Astronomy
Authors: Nayar S.R. Prabhakaran , Thomas Rebecca T.
Published: July 2016

Astronomy is the most popular and oldest of all sciences and it has had profound influence on human thought. Unfortunately, astronomy does not find an appropriate place in our school-college syllabi. This may be due to the fact that teaching of astronomy encounters a large number of problems with regard to visualization and practical experiments. Popularization of astronomy depends heavily on a large variety of astronomical events, such as the arrival of comets, eclipses, supernovae, etc. Visualization of dynamics in several directions, wide variance of time scales, concepts of space, etc., create problems in teaching/learning processes in astronomy. Our world of human experience is limited to within a narrow frame, whereas in astronomy we speak of size, time, and temperature in gigantic scales. To bring all these parameters onto the human level, one has to think of effective teaching aids and the right type of techniques. We have been using a large number of tools in teaching astronomy, including star charts, globes, models, photographs, slides, etc. Microcomputers act as an effective medium in teaching astronomy. They can even replace most of the above mentioned teaching aids (Hunt, 1986; Marx and Szucs, 1985; Sparkes, 1986). A microcomputer can also act as a textbook, a blackboard, or even a planetarium. The computer acts also as a mediator between the student and the model of some real-life situation. The process of building and using models, called simulation, helps us to investigate systems that would otherwise be inaccessible. We have developed a set of software to teach basic concepts in astronomy, such as the solar system, constellations, and the physics of stars. We have explored the possibilities of making the software interactive, using the observed data so that a real life situation can be experienced by the users, just as for practical experiments.
Introductory Astronomy Textbooks in 19th and 20th Century America
Authors: Sperling Norman
Published: July 2016

A survey of 138 introductory-astronomy textbooks spanning 152 years reveals growing consensus regarding each topic’s proportion, with some clearly gaining space at the expense of others. The tables in the texts cite curious numbers, claim too many significant digits, neglect to note uncertainties, and are frequently inconsistent with, or badly behind, the research of the times. This study investigates apportionment of topics, planet and star data tables, and categorization of nebulae.

To probe the student/textbook interaction, I used one copy of each of 40 recent introductory textbooks when teaching astronomy in Fall 1986. Students swapped books each session. Texts’ treatments were surveyed in daily recitation as well as term papers comparing and contrasting them on specific topics. Most books sound much more positive than current data justify. There was lots of confusing phrasing, shoddy proofreading, and careless assembly of data tables. A few books are shamefully erroneous. There are numerous impressive examples of the imperfection and transience of “textbook learning.” The biggest and most pervasive sin was writing in the passive voice “Official Style” of interminable sentences laden with prepositional phrases. Illustrations, while important, are secondary to phrasing. Students need and use chapter summaries, glossaries, and indices. About half prefer paperbacks and half hardbacks. Students rated the books for appropriateness to their needs. The experience may stimulate others to develop controlled experiments to probe the student/textbook interaction.
A Portable Demonstration of Orbits in Curved Space-Time
Authors: Friend David B. , Forkey Kevin
Published: July 2016

Many introductory astronomy students, when confronted with the idea of curved space-time in discussions of relativity and cosmology, don’t have a very good grasp of what this really means. They are told that the presence of mass “curves” space-time, but it is often not clear to them what is meant by that statement. We have developed a simple portable demonstration of what is meant by curved space-time, by using a two-dimensional analog. We have stretched a thin rubber sheet over a circular metal frame which is supported a few inches above a table top. By placing a heavy weight (about a kilogram) in the center of the sheet, we can mimic the effect of the curvature of space-time around a massive object on an orbiting body (such as a planet orbiting a star). We roll a small ball around the sheet, and the ball describes approximately elliptical orbits around the weight (see the photograph). The orbits aren’t exactly elliptical for two reasons: energy is dissipated by friction between the ball and the sheet, and the sheet doesn’t quite have the correct shape (it is shaped roughly like In r instead of 1/r: see this by solving Laplace’s equation in two dimensions with circular symmetry). We like to project this demonstration with a video camera placed directly above the sheet, so that the students can see the “orbit” without actually seeing the curvature of the sheet.
The Committee of Ten
Authors: Bishop Jeanne E.
Published: July 2016

The college-educated populations of colonial 18th- and 19th-century United States were reasonably well-versed in principles of elementary astronomy — perhaps not fully in spatial concepts of seasons and lunar phases, though they certainly had some correct ideas about their causes. Astronomy had found a niche in academies and in the public high schools that succeeded them. In 1838 an observatory was installed in a Philadelphia high school. The states turned to the academies and early high schools for the majority of their elementary teachers, so the teachers who completed high school in the 19th century had been taught the reasons for common astronomical phenomena and conveyed these reasons to children. Parental teaching reinforced what was taught in primary schools. Until the late 19th century, colleges continued to offer astronomy or natural philosophy as part of the general curriculum. It therefore seems that a cycle of astronomy teaching and learning rudimentary astronomy was in effect until the late 1900’s.
Popularizing Astronomy at Public Observatories in West Germany
Authors: Neumann Hans L.
Published: July 2016

Based on the pedagogical ideas of A. Diesterweg, a number of science associations have been founded since about 1880 under the name of URANIA; astronomy has been one of their subjects. In the 1920–1930’s, the works of Bruno H. Bürgel and Robert Henseling initiated the founding of many more local and regional associations and of public observatories all over the country. But most of the currently active associations were founded to answer the sharp increase of general interest that followed the early successes and spectacular results of space science.

- Aims of the associations always have been manyfold:

- to share a fine hobby with like-minded people;

- to participate theoretically or practically in scientific research as far as technical and local circumstances allow;

- to offer to the public means and advice for celestial observations, and to share the joy of deep-sky wonders with guests;

- to mediate the progress, and the results of astronomical research to the public.
Sydney Observatory Goes Public
Authors: Lomb N.R. , Wilson T.
Published: July 2016

In 1982, after a 124-year history of research, Sydney Observatory became a branch of a large local museum, the Museum of Applied Arts and Sciences. A four-year, million-dollar project was undertaken to restore the building and its grounds to their nineteenth century appearance. The services needed for a modern museum were also added. One of the larger areas became a modern lecture theater seating up to fifty people, with back projection video, film and slide projectors.

Exhibition space within the building is limited to eight rooms of approximately 200 m2 total area. To overcome this lack of space, a proposal has been made for an extension to the rear of the building. An underground 100-seat planetarium is included in the proposal. There is a great need for this as there is no planetarium currently in Sydney.
Marketing for Planetariums
Authors: Feitzinger J.V.
Published: July 2016

The sales promotion of the planetarium is a marketing problem. Program arrangements must take this into account. Marketing is not exclusively a tool to obtain a maximum profit: marketing methods can control the exchange problems between the public and the nonprofit planetarium. The planetarium produces a service. This service must be distributed to the public. The public must know that the planetarium distributes a special service.

The public visits the planetarium during leisure time. (One exception — the school classes — is not considered here.) Therefore one marketing problem of the planetarium is to sell its service as recreational value.

The leisure time activities of the public can be divided into 10 categories. These categories contain the basic patterns and needs of the public. The content of the public planetarium performances must try to cover the leisure-time categories. The communication windows of the public can only be reached by simplifying astronomical facts.
Knowledge and Wonder in the Planetarium
Authors: Dunlap J. Lawrence
Published: July 2016

Planetariums around the world attract millions of adults and children each year to public programs popularizing astronomy and related topics. For many urban school children, the planetarium experience is a unique opportunity to observe and to wonder about the night sky and objects in space. In particular, the planetarium provides children with a needed observational basis for increasing scientific literacy and for understanding astronomical concepts.

This paper explores the role of the planetarium in the astronomy education of school children, grades Kindergarten–12, in Tucson, Arizona, over the past 12 years.
Teaching of Astronomy in India
Authors: Gurm H.S.
Published: July 2016

Studies of the skies have dominated intellectual activities since ancient man. In this respect, India has a very long tradition of such recorded activity, covering the observations of celestial bodies both as a science and as mythology (Gurm, 1980). The first half of the Christian era witnessed the evolution of spherical astronomy as a part of the study of mathematics (algebra and trigonometry) and its application to astrology. The evolution of spherical astronomy culminated in the concrete manifestation in the northern parts of India in the form of Jantar-Mantars by Raja Jai Singh (Mayer, 1979) in the early eighteenth century. Interestingly, spherical astronomy remained one of the most important activities in the study of astronomy during the British period too. Some of the older treatises on this subject during the nineteenth century were written in the Offices of the Survey of India.
The Visiting Lecturers Program at San Marcos University
Authors: Aguilar María Luisa H.
Published: July 2016

Professors and students of San Marcos University (USM) have found that the Visiting Lecturers Program (VLP) of the IAU has helped to improve the study of astronomy in Peru. The Peruvian people and I are profoundly grateful.

The VLP and the International Schools for Young Astronomers (ISYA) advised us, pointing our perspectives and capacity for work in the correct direction. I feel that both the VLP and the ISYA are noble expressions of the universal message of scientific collaboration, and are the voices of the highest altruism of the astronomers who participate in them.

With reference to the VLP, the state of astronomy education can be described in three parts:
The Summer Schools of the Vatican Observatory
Authors: McCarthy Martin
Published: July 2016

Starting on the 10th of June, 1986, the staid and quiet halls and courtyard and corridors, including the giant circular staircase designed by Bernini for the little donkeys that carried Popes to their quarters in the summer palace, echoed to the swift patter of lightfooted students and the buzz of their conversations as 17 young men and 8 young women met at the first Vatican Observatory Summer School in Astronomy and Astrophysics at Castel Gandolfo.

These 25 scholars had been chosen from a list of 135 candidates at university and graduate school campuses all over this planet. More than 30 candidates were rejected for “excellence”; they were judged to be too far advanced for admission to the classes on Galaxies and Dark Matter and to those on Spectral Classification and on Instrumentation for Photometry and Image Processing. The classes were aimed at students just beginning or planning immediate entrance into graduate level classes; the School was not planned for “new Ph.D.s,” for “post-docs,” or for those already well into thesis work. Criteria for admission included academic grades, recommendations of university professors, plus personal statements from the candidates on reasons why they felt they wanted to attend the sessions of the school. Applications were studied by faculty and staff members and results were announced in January, giving students some four months to arrange their travel and home commitments so they could be free to respond to the school bells on June 10.
The Travelling Telescope
Authors: Brückner Dieter W. , Percy John R.
Published: July 2016

Astronomy is deeply rooted in the culture of almost every society, including those in the so-called “developing countries.” By virtue of its fundamental applications and implications, it has had a profound influence on philosophy and on religious ritual and belief. Astronomy is vigorously pursued in the industrialized countries where, with multi-million-dollar facilities on the ground and in space, exciting discoveries in astronomy are constantly being made. In the developing countries, astronomical research and teaching activity ranges from little to none. There is tremendous potential for growth, however, especially if the industrialized countries can be persuaded to help. At any time, there are several countries which are in the process of raising their astronomy to a level at which they can become full members of the international professional astronomical community. The IAU strongly supports this process.
500 - 3200 Å Observations of the Interacting Binary Stars V356 Sgr and β Lyr
Authors: Polidan R. S.
Published: July 2016

In this paper we present new results from the Voyager ultraviolet spectrometers and the IUE spacecraft on V356 Sgr and β Lyr. The V356 Sgr observations cover, in detail, two eclipses and include one IUE high dispersion SWP image. During both eclipses the total strength of the UV emission lines were found to be invariant. Also, an uneclipsed UV continuum was detected at wavelengths shorter than 1600 Å. The IUE high dispersion SWP spectrum revealed that the emission lines are extremely broad, almost symmetrical lines with weak, slightly blue shifted absorption components. No evidence of carbon is seen in the emission or absorption spectrum of V356 Sgr in eclipse. A model for the origin of the circumstellar matter in this binary system is presented. The Voyager ultraviolet observations of β Lyr show a strong far-UV continuum that is detectable down to 912 Å The far-UV continuum flux level was variable on time scales shorter than the orbital period and displayed no obvious orbital modulation or eclipses. The spectral shape of the far-UV continuum closely resembles that of a UX UMa type cataclysmic variable. On 16 August 1985 an rapid brightening of the far-UV continuum was observed which was also reminiscent of cataclysmic variables. Analysis of the β Lyr data suggest that the central object must be small, with a radius on the order of 1 R⊙ or less.
Resolving Information on Algol Systems
Authors: Budding Edwin
Published: July 2016

Our awareness of the facts on Algol systems, arising from both statistical evidence and examination of particular examples, is presented. The statistical information derives from the author’s recent catalogue of Algol-type candidate stars. The particular cases of R Ara and W Cru are considered. The presence of undiscerned background factors in these systems exemplify persistent threats to the confidence we place on parameter sets characterising any models we may form of such objects.
New Ways to Rotation Rates
Authors: Wilson R. E.
Published: July 2016

Progress in determining rotation rates of Algol primary stars from light curves is assessed. Included are elementary ideas on why the new method works, how to carry out solutions, and how and when to apply the constraint on rotational lobe filling. Some comments are made on desirable improvements for measuring rotation from line broadening. A few remarks are made about the problem of identifying likely fast rotating Algols.
An Optical and Ultraviolet Survey of Algols
Authors: Dobias Jan J. , Plavec Mirek J.
Published: July 2016

We present a table of results from our survey of Algols, conducted with the Lick Observatory ITS scanners and the IUE spectrometer.
The B-Type Semidetached Binary BF CEN in NGC 3766
Authors: Helt B.E. , Andersen J. , Kämper B.-C.
Published: July 2016

Binaries in clusters are particularly important: If unevolved, they may provide a check of the mass predicted for the point on the cluster Isochrone where they are found. If mass-exchange has occurred, the age and chemical abundance inferred from other cluster stars provide useful boundary conditions for theoretical models of binary evolution involving mass exchange. With these goals in mind, we have studied the early-type (B2+B6), 3.7-day eclipsing binary BF Cen in the young cluster NGC 3766.
Spectroscopic Observations of the Early-Type Contact Binary AW Lacertae
Authors: Nakamura Y. , Okazaki A. , Katahira J.
Published: July 2016

Spectroscopic observations were performed of the early-type contact binary AW Lac with an image-intensified coude spectrograph of 1.9−m telescope at the Okayama Astro-physical Observatory. A total of twenty-two spectra covering blue region with a dispersion of 16 Amm−1 have been secured on Kodak IIa-O baked plates. In every spectra sharp interstellar Call H,K lines are clearly seen. The spectral type of AW Lac has been estimated as early B, which substantially confirms the one adopted in the photometric analysis by Jiang et al. (1983) and is diffrent from A0 listed in General Catalogue of Variable Stars (Kholopov et al. 1985). Contrary to the suggestion by the photometric solution of Jiang et al., no definite secondary lines could be separated, though some indications of light contamination due to the secondary component are surely observed. This would imply that the light ratio of the components should be somewhat smaller than that derived by photometric analysis. No emission features appeared either. The measurement of radial velocities of the primary component for the orbital elements was made for twenty spectra by a conventional method. It was difficult to measure the radial velocities because the lines are quite broadened and deformed. Hence the measured values for the radial velocities should be regarded as rather preliminary. The derived spectroscopic elements, combined with the photometric data, give the absolute dimensions of the system for each assumed mass ratio q. For q = 1, being the adopted photometric solution by Jiang et al., we obtain too small value for the primary’s mass, comparing with its spectral type. For the mass ratio as small as q = 0.6, we can obtain a reasonable value for the mass of the primary. However, in order to get more definite conclusion the cross-correlation method would be more appropriate for the spectroscopic analysis of this system.
Light Curve Analysis and Evolutionary Status of the RS CVn type Eclipsing Binary RZ Eridani
Authors: Rao P. Vivekananda , Rao B. V. N. S. Prakash , Sarma M. B. K.
Published: July 2016

Photoelectric observations of the long period RS CVn type eclipsing binary RZ Eridani were made with the 1.2m reflecting telescope of the Japal – Rangapur Observatory during the observing seasons 1976-79. We could not obtain a full light curve in any one season and therefore the combined light curve is used for analysis. No distortion wave was found in this system. The period of the system (39ḍ282466) is found to be constant during the period 1906 to 1979. From W-D solution we obtained the eccentricity to be zero whereas Popper (private communication) from his spectroscopie studies, suggested a value of e = 0.339 for the eccentricity. Such disagreement between the photometric & spectroscopic eccentricity values is reported in the system SX Cas (Struve 1944 Ap.J, 99, 89., Shao 1967 A.J, 72, 480). This might be due to circumstellar matter covering the whole system. The ultraviolet excess found by us in RZ Eri is similar to that found in systems like SX Cas, RX Cas, βLyr & W Ser
The Binary system V380 Cygni
Authors: Battistini P. , Bonifazi A. , Guarnieri A. , Lolli M.
Published: July 2016

This binary system, according to Semeniuk and Paczynski (1971), is very interesting because it is probably in a phase of rapid evolution through the Hertzsprung gap in the HR diagram and shows apsidal motion (Battistini et al. 1974) .

The system was Observed at the Bologna Astronomical Observatory in UBV because the only known light curve (Kron 1935) is insufficient to give appropriate orbital elements (Kopal 1940, Ramella et al. 1980) and it is impossible to fit photometric elements with spectroscopic results (Batten 1962). The observations started in 1970 and ended in 1973; in 1980 the system was reobserved to complete light curve coverage.
The Old Nova BT Monocerotis
Authors: Seitter W. C.
Published: July 2016

Spectroscopic observations through most of the eclipse cycle of BT Mon reveal the presence of both low and high velocity gas streams. Acceleration through a Laval-nozzle-effect at the inner Lagrangian point of the system and powering of the emission lines through kinetic energy losses of Coriolis deflected and subsequently colliding gas streams are considered as possible mechanisms at work in the system.
The Contact Binary AE Phoenicis - An Analysis from Deconvoluted Spectra
Authors: Becker H. J.
Published: July 2016

A method is described for an analysis of deconvoluted stellar spectra, and applied to new spectroscopic observations of the close eclipsing system AE Phuenicis, obtained with the 1.52 m telescope of the Southern European Observatory at La Silla, Chile. Results are presented for the rotational velocities of this variable, together with a proposed model of the system.
Spectroscopic Segregation in Binary Systems
Authors: Darius Jon
Published: July 2016

Binary systems displaying spectroscopic segregation, whereby line spectra of the two components overlap little or not at all in wavelength, account for a small subset of LUV objects (late-type ultraviolet). Optical and ultraviolet (IUE) spectra for one such system, HD 15351 + UV0225 + 13 (F4-5 V + sdO), are presented and a few related systems described. The role of LUV objects in establishing an absolute luminosity calibration for hot subdwarfs is emphasized, along with their significance for stellar evolution. A search strategy for additional spectroscopically segregated LUV objects is outlined.
Magnetic Braking in Cataclysmic and Low-Mass X-Ray Binaries
Authors: Vilhu O.
Published: July 2016

The chromospheric-coronal emission of lower Main-Sequence single and binary stars can be correlated with an activity parameter of type R = g(B-V)P-1 where P is the rotation or orbital period and g(B-V) a function of the color resembling the convective turnover time. Observations indicate that the active region area coverage filling factor grows as R2, and the whole stellar surface becomes filled with closed loop structures at R ≂ 3. A braking formula is proposed (Equation 4) to include all periods (0.d1 ≲ R ≳ 30d) and spectral types F-M. On the basis of this equation, the mass transfer rates in compact binaries (driven by the gradual loss of orbital angular momentum) are discussed. It is concluded that the magnetic braking has good chances of being that mechanism which drives the mass transfer in cataclysmic variables and galactic bulge X-ray sources.
Diameter Measurements of Asteroids
Authors: Dollfus Audouin
Published: July 2016

Direct optical measurements of asteroid diameters obtained by telescopic observations are scarce. Although several adequate instrumentations and techniques are available for the purpose, they have not been used. The importance of these determinations should be stressed for the attention of observers.

The filar micrometer was used only by one observer during the last century, and no additional measures have been made since. This was in 1894 and 1895 when E. Barnard (1902) used the 90 cm refractor of Lick Observatory, and the 100 cm refractor of Yerkes Observatory. The results are as follows:

Ceres: apparent diameter at 1 AU: l˝.060, or 770 km (28 nights)

Pallas: apparent diameter at 1 AU: 0˝.675, or 490 km (5 nights)

Juno: apparent diameter at 1 AU: 0˝.266, or 195 km (5 nights)

Vesta: apparent diameter at 1 AU: 0˝.531, or 390 km (21 nights)
Asteroid Polarimetry: A Progress Report
Authors: Veverka J.
Published: July 2016

This is a brief report on the present status of asteroid polarimetry. A detailed paper is in preparation jointly with T. Gehrels.

The first polarization measurements of asteroids were made by Lyot (1934), who photographically determined the polarization curves of Ceres and Vesta. These curves are reproduced by Dollfus (1961). Unfortunately, because of the low sensitivity of the photographic method, they do not agree very well with recent photoelectric measurements.

The first photoelectric polarization measurements of asteroids were made by Provin (1955) (details of this work are given by Dollfus, 1961), and in recent years this work has been extended by Gehrels (unpublished) and by Veverka (1970). To date, fairly complete polarization curves for about a dozen asteroids have been obtained, and at least partial data are available for twice that number.
Photometric Observations and Reductions of Lightcurves of Asteroids
Authors: Taylor Ronald C.
Published: July 2016

The brightness-time variation (the lightcurve) of an asteroid is observed to obtain the rate of rotation, some indication of the shape, and the orientation of the rotation axis in space. The brightness-phase relations are observed for the study of surface texture.

This paper deals specifically with observing routines and reductions, including discussions of lightcurves, rotation periods, absolute magnitudes, phase coefficients, opposition effects, and pole determinations. This paper supplements the review chapter by Gehrels (1970). Only photoelectric techniques are considered because the visual and photographic ones are, nearly without exception, not precise enough.
Lightcurve Inversion and Surface Reflectivity
Authors: Lacis A. A. , Fix J. D.
Published: July 2016

A simplified lightcurve inversion method is applied for the special case where observations are taken in the equatorial plane of the asteroid The solution is obtained in terms of a spotted two-surface model using Lambert’s law and geometrical reflectivities.
Descriptive Survey of Families, Trojans, and Jetstreams
Authors: Van Houten C.J.
Published: July 2016

The word “group” is so general that I would like to suggest that here it is used in its most general way: a group of asteroids is a collection of minor planets that have some feature in common. If we agree on this use of the word “group,” then we can discern the following asteroidal groups:

(1) Groups that have a dynamical cause:

(a) Trojans

(b) Commensurability groups:

(i) Hungaria group

(ii) Hilda group

(iii) Thule

(2) Groups that probably have no dynamical cause:

(a) Hirayama families

(b) Brouwer groups

(c) Jetstreams
The Palomar-Leiden Survey
Authors: Van Houten C.J.
Published: July 2016

The Palomar-Leiden survey (PLS) was set up as an extension to fainter magnitudes of the McDonald survey. The latter is, therefore, the more important survey as far as asteroid statistics are concerned. The main result of the PLS is that no clearcut differences exist between the fainter asteroids found in this survey and the numbered asteroids in the distribution functions of eccentricity, inclination, and semimajor axis and that the statistical relations found in the McDonald survey have a continuous extension in the PLS material. I would, therefore, propose not to summarize the results of the PLS, which would appear to be a tedious job, but to give here some new results that should properly have been included in the publication, but, for reasons of pressures to publish as soon as possible, were not.