bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compact Binary X-Ray Sources
Authors: McCray Richard 
Published: July 2016

AbstractCompact binary X-ray sources include white dwarfs, neutron stars, and black holes that are accreting matter from a companion star. The X-ray emission from these systems is produced by the accreting matter as it flows through an accretion disk and strikes the surface of the compact object. The emitting regions have opacities dominated by electron scattering, and radiation pressure is likely to play an important role in the hydrodynamics. Strong magnetic fields greatly modify the hydrodynamics and radiation transfer in the pulsating neutron star sources. Accretion disks have complex structure, including an electron scattering corona, a cool outer region, and possibly a thick torus in their inner region. The structure and stability properties of accretion disks are only partially understood. Major problems exist with the interpretation of the spectra and luminosities of the X-ray burst sources. The pulsed X-ray emission from the pulsating binary X-ray sources probably comes from “mounds” of accreting gas at the magnetic poles of neutron stars, in which the accreting matter is decelerated by radiation pressure. The physics of these systems is reviewed, with an emphasis on problems for which hydrodynamical simulations may be especially useful.
Curriculum for the Training of Astronomers
Authors: Narlikar Jayant V. 
Published: July 2016

In a discussion on the training of astronomers, the question naturally arises: “Training...but at what level?” After all, the subject of astronomy happens to be unique amongst all sciences in that it interests children and educated general public at one end and professionals at the other. Before coming to these specifics, certain general remarks will be in order.Astronomy is a branch of science. This fact is not readily appreciated at the “lay” end of the above spectrum. Unlike other sciences, which have Earth-based laboratories in which controlled experiments are performed, astronomy has its labs located in the heavens far beyond the reach, let alone “control,” of the terrestrial observer. So how can one be sure that what one sees out there is subject to the same rules and disciplines of science that govern the local laboratory experiments of physics and chemistry? Yet that happens to be so!
A Self-Paced Mastery-Oriented Introductory Astronomy Course
Authors: Safko John L. 
Published: July 2016

I will be describing a self-paced mastery-oriented introductory astronomy course that has been offered at the University of South Carolina since 1972. This course is a three-semester sequence with total enrollments of 800–1000 students per term. Most of the enrollment is for the first semester of the sequence. Although these particular courses are designed for non-science majors, I believe that the methods developed in these courses can be applied to courses for astronomy majors. These methods could provide a solution to the problems of teaching classes and, at the same time, traveling for research and meetings.A mastery-oriented course involves developing a list of learning objectives that are described in terms of performance of given tasks. That is, words such as understand and appreciate should not be used. Performance objectives involve words such as recognize, calculate, measure, and describe. Any set of learning objectives must be tied to a set or readings, a textbook, and/or supplementary notes. These items are chosen or written by the instructor(s) to provide the background necessary for the students to master the objectives.
Laboratory Activities in the Teaching of Astronomy
Authors: Osborn Wayne 
Published: July 2016

Astronomy is one of the most popular of the sciences. That this is so can be seen in the frequent news articles about astronomical discoveries and happenings, in the number of questions about the sky fielded by planetarium and observatory staff, and in the large turnouts for public observing sessions at observatories or astronomy club star parties.Another reflection of astronomy’s popularity is the fact that thousands of university students study the subject each year. Only a few of these are training to become professional astronomers. The vast majority of these students seek mainly to obtain a general background. An important subset of the latter group are those students preparing to teach in the schools and who have the need to understand, and be able to explain, common astronomical phenomena clearly. Those of us who teach introductory astronomy courses have an obligation to ensure that these prospective teachers are well trained.
Microcomputers in the Teaching of Astronomy
Authors: Dukes Robert J. 
Published: July 2016

There are many ways to use computers in teaching. This paper discusses one of those ways: as an adjunct to the introductory astronomy course as taught in the United States.The computer allows the demonstration of phenomena in a graphic dynamic manner, so its use can enable students to gain a deeper understanding of the material than they might when they passively listen to a lecture, look at slides, or study a textbook. In a very real sense, material presented in a computer is similar to that presented by film or video, but with one major difference: viewing movies is essentially a passive experience while interacting with a computer is an active one. Using computer simulations, the user can vary initial conditions and observe the effect of changes. This ability is the case whether the person doing the interacting is the instructor during a lecture or the student during a lab or while independently executing a homework exercise.
Textbooks for Developing Countries
Authors: Othman Mazlan 
Published: July 2016

I would like to address the issue of textbooks from a developing country’s point of view.Firstly, I believe that in the developing countries a textbook should be written in the native language if it is to reach the very people whose awareness of astronomy needs to be raised. And when we talk about books in the vernacular, the problem is one of dearth: a dearth of writers and a dearth of resources.The lack of writers comes about simply because in the developing nations there are inevitably very few astronomers and of these only one or two will be inclined to write books. If there exist writers, they are faced with several choices and problems. There are three types of books which can be written: a university text, a school text, and I shall include a book for the public. Each type of book targets a different kind of audience, so the writer must be attuned to the needs of the nation to know what the priority should be. If, for example, astronomy is about to be introduced into a school curriculum, then a school textbook should take the highest priority because it tackles astronomy education at the grass-roots level. Naturally, the final choice will depend on other factors as well, including promotion, fame, and pecuniary considerations.
Science Teaching through its Astronomical Roots
Authors: Sadler Philip M. , Luzader William M. ,   Project STAR
Published: July 2016

Project STAR (Science Teaching through its Astronomical Roots) emerged from growing concern about the decreasing enrollment in science classes, and lack of understanding of science and math concepts (Figure 1). Using astronomy as a focus, Project STAR is trying not simply to increase the enrollment in high school science courses, but also to improve the students’ understanding of science and its role in making sense of the world.The educational approach of Project STAR is based on three principles:• Mastery of a few ideas is more important for students than cursory exposure to many concepts.• Students learn best through hands-on activities.• Students enter the classroom with certain preconceptions, or “naive theories,” about how physical systems work, without a sense of whether their understandings are accurate (often they are not).
The Week-End Astronomy Class for Teachers
Authors: Hensley James H. 
Published: July 2016

Astronomy is an integral part of many high-school science programs. Project STAR and the Science Assessment and Research Project at the University of Minnesota have recently recognized this. In addition, astronomy is a part of most elementary and middle-school science programs. In the Platteville, Wisconsin, school system, the solar system is a unit of study for all third grade students and a study of the stars is a part of the eighth grade science program. This is also true for other school systems in this area, in the Chicago area, and I would suspect, across the nation.However, most elementary school teachers have had little science course work and none in astronomy. Middle-school and high-school teachers have better backgrounds for teaching science but little or no astronomy course work. Some of those who teach astronomy are active in local astronomy groups and read Astronomy or Sky and Telescope magazines, but this is the exception rather than the rule.
The Didactic Activities of the Italian Astronomical Society
Authors: Pestellini M. Elena Dilaghi 
Published: July 2016

The Italian Astronomical Society is one of the oldest Italian scientific associations: founded in Rome in 1871 as the Society for Italian Spectroscopists, it includes professional as well as amateur astronomers and teachers among its 800 members.In the last 10 years, the Society has been concerned with the problems of teaching, as a result of the enormous demand from schools where astronomy is often not well taught at any level because of a lack of suitable qualified teachers.To meet this need, the Society publishes a quarterly journal entitled Il Giornale di Astronomia, which includes news of astronomical events, informative articles and accounts of didactic experiences as well as other information that may be helpful to teachers of astronomy.
The Teaching of Astronomy and Social and Economic Development
Authors: Vicino Gonzalo 
Published: July 2016

Sometimes we may ask ourselves how can astronomy, a science with apparently few points of contact with technology or industrial production, help the economic development of people?My paper is an account of an experiment undertaken in Uruguay on the teaching of astronomy in secondary schools. We seek to show how astronomy may contribute to the development of nations that, like Uruguay, need to create their own technologies to overcome their economic backwardness.Though the introduction of astronomy in the secondary education curriculum in Uruguay dates back to 1889, in 1986 the Educational Supervisory Office made a radically different proposal for the methodological and programmatic orientation of astronomy teaching. The proposed goal is clear: the teaching of astronomy in secondary education should be geared not to train technicians but to create a scientific-minded youth. It is not important if later, in their university studies, these young people go into medicine, engineering, or economics; the important thing is a reevaluation of sciences in the eyes of adolescents, who often slide along the comfortable slope of certain humanistic areas, in which they wind up by the process of elimination. (One often hears the argument, “I’m studying law because it doesn’t have mathematics.”) Further, above all those considerations, the most important thing is to create thinking minds, the minds of free people.
AY Vulpeculae
Authors: Walker R.L. 
Published: July 2016

The star AY Vulpeculae was recognized as variable and labeled as an Algol-type system by Hoffmeister, (A.N. 242, 133, 1931). Koch et al. (I.B.V.S. 1709 1979), included it in their list of eclipsing binaries for which photoelectric work was needed. The system is faint, but because its primary minimum is very deep it is of astrophysical interest. The observations of the present investigation represent the first definitive photometric study made of AY VUL and is one of several systems with periods greater than two days being observed with the 1.0 meter Ritchey-Chretian reflector at the Flagstaff Station . A total of 1242 observations of AY Vul (406 in V, 417 in B, and 419 in U) were obtained on 12 nights in 1986.Orbital elements for AY VUL were obtained by using the Wood model, and the calculations were performed on the VAX 11/750 computer at the Flagstaff Station of the U. S. Naval Observatory. AY Vulpeculae can be regarded as a classical Algoltype semidetached system in which the secondary component fills its Roche lobe, while the primary lies well inside its own lobe. Both eclipses are partial. The orbital elements are listed below.
UV Observations of Three Classical Novae during Early Stages of Decline
Authors: Drechsel H. , Wargau W. , Rahe J. 
Published: July 2016

AbstractWe present IUE UV spectra of the three recent classical novae N Sgr 1982, N Ser 1983, and N Mus 1983, obtained during early decline, transitional stage, and nebular phase, respectively. The line spectra are discussed. Preliminary conclusions concerning CNO over-abundances, shell geometry, and speed classes are drawn.
A Review of Early-Type Close Binary Systems
Authors: Leung K. C. 
Published: July 2016

AbstractThis is a review of close binary systems with very early spectral types (B, O, Of, and WR stars). We limit our selection to systems with Roche model photometric solution only. There are 10 contact systems known at present. Three of them (V701 Sco, BH Cen, and RZ Pyx) are located in the vicinity of the zero-age contact (ZC) according to a Spectral Type - Period diagram. Only the first two systems have absolute dimensions available. Both of these fall into the ZC zone in the logP - logm diagram and the logm - logR diagram. The system TU Mus was thought to be a ZC system is located in the evolved contact zone (EC) in the above diagrams. Both V701 Sco and BH Cen were thought to be having mass ratios about unity. With the much improved light curves of BH Cen and new analysis the mass ratio has been revised to 0.84! This result may favor Shu's model for early-type zero-age contact systems. The evolved systems might be undergone Case A mass exchange except for two systems (V729 Cyg and RY Set) which might be from Case B. The systems V367 Cyg was classified by Plavec as a W Ser system may be a evolved contact system.It is interesting to note that V729 Cyg (07f + Ofla), UW CMa(07f + O) and CQ Cep(WN7 + O) are all highly evolved contact systems. The Max II of UW CMa and CQ Cep are displaced to 0.78 and 0.80 phase, respectively. The displacement for V729 Cyg is not known due to poor coverage at this phase. The most distinct feature going from Of to Wolf-Rayet stars is the increasing domination of emission lines. It is suspected that this phaseshifts reflect the increasing activity of mass-flow in the common envelope.There are 8 semidetached systems with reliable absolute dimensions. It is believed that 6 of them are derived from Case A while the remaining 2 are from Case B mass exchange.
A Spectroscopic Study of Epsilon Aurigae
Authors: Saitō Mamoru , Kawabata Shusaku , Saijo Keiich , Sato Hideo 
Published: July 2016

AbstractEpsilon Aurigae has been observed during ingress and totality between 1982 and 1983 at Okayama. Analyses of profiles of Ha line and of radial velocities of neutral hydrogen and metals show that the secondary component consists of at least three parts in structure.
Absolute Intensity Calibration at 26 Å by Branching Ratios to the Visible
Authors: Irons F. E. , Peacock N. J. 
Published: July 2016

The technique for absolute calibration using the branching ratio of two transitions which have a common upper level but widely separated energies has been employed and described by Griffin and McWhirter (1961).Using the plasma produced by irradiation of a carbon target with a 1 GW, 6 nsec duration, neodymium laser pulse, we have been able to calibrate a grazing incidence spectrograph at the wavelength (25.83 Å) of the 7–1 transition in C VI by direct comparison with the intensity of the 7–6 (3434 Å) transition emitted from the same ions in the plasma. The spectrum from a similar carbon plasma has been described by Boland et al. (1968) and in several ways is ideal for this type of measurement.
Identifications of Some Highly-Ionized Iron and Nickel Lines in the 200–400 Å Region of the Solar Spectrum
Authors: Widing K. G. , Sandlin G. , Cowan R. 
Published: July 2016

AbstractA number of previously unclassified multiplets of FeXIV, XIII, XII, and XI produced by transitions of the type 3s23pn–3s3pn+1 are identified in the XUV spectrum of the Sun. The iron lines account for most of the previously unidentified strong lines between 330 and 370 Å. Solar observations of especial value for the investigation of the 300–400 Å region were the slitless spectroheliograms of September 22, 1968 (Purcell and Tousey, 1969) and November 4, 1969 (Tousey, 1971) – on which the image of a flare was recorded.Other solar identifications in the same spectral region include the resonance lines of NiXVII and NiXVIII, and one 3p–3d multiplet of FeXIII. The solar blend at 417 Å involving the FeXV inter-combination line and SXIV is resolved.
Photometric and Spectroscopic Variability of the Hydrogen-Deficient Binary CPD-58°2721
Authors: Morrison K. , Drilling J.S. , Heber U. , Hill P.W. , Jeffery C.S. 
Published: July 2016

AbstractThe hydrogen-deficient star CPD-58°2721 (=LSS1922) has been observed to show radial velocity variations with a range of 140 km s−1. It shows light and colour variations with amplitudes of 0T07 on a timescale of about 9 days. The absorption spectrum is nitrogen-rich and is seen to vary on a short timescale (4 days). CPD-58°2721 therefore appears to be a hydrogen-deficient binary similar to KS Per and v sgr. The photometric variability is attributed to radial pulsation.
Evolutionary Status and Origin of Extremely Hydrogen-Deficient Stars
Authors: Schönberner D. 
Published: July 2016

AbstractOur present knowledge about the evolutionary status of extremely hydrogen-deficient stars is reviewed. Possible schemes for their creation are discussed, with special emphasis on a recently proposed binary scenario, according to which they are the result of the merging of two white dwarfs. Finally, the possible generic links between the different groups of extremely hydrogen-deficient stars are briefly discussed.
β Lyrae - A Binary System with Anomalous Abundances and Magnetic Field
Authors: Skul'skij M.Yu. 
Published: July 2016

AbstractStudy of dependence of chemical abundance on conditions of excitation within the limits which could exist in the atmosphere of bright component have led to conclusion that by no modification of physical parameters a “normal” abundance of chemical elements in the atmosphere can be obtained. The variable effective magnetic field with mean value (−1350±50) Gauss is discovered.
Gallium Overabundance in the Ap-Si Star HD 25823
Authors: Artru Marie-Christine , Ferrero Rubens Freire 
Published: July 2016

AbstractAn anomalous enhancement of the resonance line of Ga II at 1414.44 Å is observed in IUE spectra of the silicon star HD 25823. High-resolution spectrum of this star is compared to synthetic spectra calculated in the range 1406–1422 Å. The LTE abundance of gallium is evaluated to log NGa = 6.3 ± 0.5 in the scale where log NH = 12.
The LI I 6708 Feature in CP Stars
Authors: Faraggiana R. , Castelli F. , Gerbaldi M. , Floquet M. 
Published: July 2016

AbstractPreliminary results are presented on the behaviour of the feature at 6708 Å; the location of the observed feature coincides with the doublet of Li I 6707.761 and 6707.912 Å.
Seventeenth-Century Solar Observations: Fundamental Results with Amateur Instruments
Authors: Ribes-Nesme E. , Ribes J.C. 
Published: July 2016

AbstractThe equipment used by professional astronomers in past centuries was no better than that used by modern amateurs. Systematic observation of the Sun began in the 17th century and continuity of observations is very important for understanding the solar cycle.Results obtained from historical observations were presented, in particular covering the Maunder Minimum.Continued systematic observation is important for the understanding of long-term solar-terrestrial relations.
Sailors and Astronomy
Authors: Demerliac Antoine 
Published: July 2016

Sailors are neither professional nor amateur astronomers, but people who have to observe the sky in the course of following their professional calling. As soon as sailors ventured far from the coast they required some guide and even in antiquity (as shown by mentions in Homer’s Odyssey and, considerably later, by Aratus) they used Ursa Minor and Ursa Major. With journeys farther afield, they gained some insight into latitude from the changes of the altitude of the circumpolar constellations above the horizon. Although the very last Viking voyagers knew of the magnetic compass, earlier ones still relied on the Sun and the stars. Describing the methods used, Harald Akerlund says “One saga mentions a man, Oddi Heldagon, who was known as “Oddi the Star” and who served as long-distance pilot for an Icelandic magnate towards the end of the 900s. He left notes that included a complete table of the changes in declination of the Sun throughout the year, expressed as the height of the Sun on the meridian in semi-diameters. There is also a small table of azimuths giving the direction at different times of the year, of dawn twilight, defined as being a faint band of light on the horizon, visible before sunrise. We know nothing of the instrument used to measure the altitude of the Sun.”
A Study of Disconnection Velocities in the Plasma Tail of P/Halley
Authors: Caron Roland , Koutchmy Serge , Sarrazin Michel 
Published: July 2016

During a photographic campaign on Comet P/Halley in 1986 April, a considerable number of photographs were obtained, especially on April 8, of a disconnection event in the plasma tail. Initial details were presented at the Symposium in Heidelberg at the end of 1986.The photographs were obtained with a camera five examples of which were specially constructed (by Carron), and known as the K600. The objective is a 100-mm OG, focal length 600 mm and the image is corrected with a field lens. The camera body is a Hasselblad, taking 120 roll film, which was Agfa 1000.
Chromospheric Eruptions Observed with a Wide Slit
Authors: Costard François 
Published: July 2016

AbstractThe method of placing the solar limb tangential to the slit, which is then widened, has been employed. The following phenomena have been observed: fast radial motion of low loops; extension of the main loop into the corona; ejection of material from the top of the loop; rotation of the structure as it relaxes.
The European Section of IOTA: Scientific Programme Coordination and Results
Authors: Breisker W. , Bode H.J. 
Published: July 2016

AbstractLunar occultations and occultations of stars by planets and asteroids are important tools in determining astrometric information as well as details about the occulting bodies. Successful work requires a relatively large number of small observatories, well-distributed over a large area of the Earth. This is particularly important in occultations by asteroids because the accuracy of the predictions is generally poor.Cooperation is therefore essential. IOTA/ES (European Section of the International Occultation Timing Association) provides a means of cooperative work, and holds meetings in different European countries about once a year. Eastern European countries are included.Some results of occultations were presented and future events discussed. A relatively cheap photoelectric system was described, very suitable for amateurs and public observatories.