bluuebunny/crossref_metadata_2025 huggingface dataset:
FG Sagittae
Authors: Schönberner Detlef , Jeffery C. Simon
Published: July 2016

FG Sagittae has evolved from a hot central star of a planetary nebula to an K-type supergiant within approximately the last 100 years. The generally accepted interpretation for this redward evolution is that of a late thermal pulse during the planetary nebula stage, wherein helium burning at the surface of the electron-degenerate carbon-oxygen core is reignited. As the star expands in response to the energy released by helium burning, envelope convection digs deeper and deeper until nuclearly processed material may get dredged-up to the stellar surface. Analysing the spectra as FG Sge is evolving would then give unique information about the temporal development of mixing processes occurring inside the star that are otherwise impossible to obtain. The existing abundance analyses do not give, however, a consistent picture. Especially the question about FG Sge’s hydrogen abundance is still unsettled. We present a critical assessment of all the existing data, trying to find a self-consistent picture of the evolution of FG Sge, based on the latest evolutionary models.
Sakurai’s Object, V605 Aql and FG Sge: An Evolutionary Sequence Revealed
Authors: Lawlor Timothy M. , MacDonald James
Published: July 2016

We have completed a grid of stellar evolution calculations to study the behavior of the born again phenomenon. All our evolutionary sequences begin with a uniform composition 1 M⊙ star on the pre-main sequence Hayashi phase and end on the white dwarf cooling track. We find a very late thermal pulse occurs in 10 – 15 percent of cases. Our models supply an answer to the question of why the born again stars V4334 Sgr (Sakurai’s Object) and V605 Aql have a significantly shorter evolutionary time scale than the otherwise similar born again star FG Sge. Models with low convective mixing efficiency, η = 10–4, first evolve quickly to the AGB, return to the blue, and then evolve more slowly back to the AGB for a second time before finally returning to the white dwarf cooling track. The difference in evolution time scales can then be explained by proposing that Sakurai’s Object is evolving to the AGB for the first time but FG Sge has been observed during its second return to the AGB.
The β Lyrae Puzzle
Authors: Linnell A.P.
Published: July 2016

Accurate simulation of optical wavelength CCD spectra is possible by adopting a black-body representation for the radiation characteristics of the β Lyrae accretion disk rim. Application of this model to IUE spectra shows that the anomalous system light curves, in the satellite UV, arise from a source of radiation, not included in the current model, which is visible during the phase 0.0 eclipse.
Magnetically Driven Warping and Precession of Accretion Disks: Implications for Exotic Stellar Variabilities
Authors: Lai Dong
Published: July 2016

The inner region of the accretion disk around a magnetized star is subjected to magnetic torques that induce warping and precession of the disk. These torques arise from interactions between the stellar field and the induced electric currents in the disk. These novel magnetic effects give rise to some “exotic” stellar variabilities, and may play an important role in explaining a number of puzzling behaviors related to disk accretion onto magnetic stars, such as mHz QPOs in X-ray pulsars, long-term periodicities of X-ray binaries (including precession of jets), low-Frequency (10-50 Hz) QPO’s in low-mass X-ray binaries, and photometric variabilities of T Tauri stars.
The Later Evolution of the Contact Binaries AP Leo, AK Her, AB And and AM Leo
Authors: Li L. , Han Z. , Zhang F.
Published: July 2016

A detailed study of the periods and light curves of binaries AK Her, AP Leo, AB And and AM Leo is presented. Based on the study of the O – C curves, we find that the period variation of each system contains several components with different frequencies, and we suggest that the periodical variations in the periods are likely influenced by different mechanisms. Based on the study of the light curve changes, we find that the light curves exhibit two kinds of variations: rapid variations and long-term variations. We investigate the physical mechanisms which may underlie the variations of the period and the light curve of each system and obtain some new conclusions. According to the characteristics of the rapid light variation in these systems, we suggest that the rapid change in the light curve is probably caused by pulsation of the common envelope, and that the mechanism(s) causing the pulsation may be mass transfer through the inner Lagrangian point L1 or its variation. Finally, the evolutionary trends of these systems are discussed, and we suggest that these systems may be progenitors of cataclysmic variables.
Variability of the Light Curves of the Close Binary GR Tauri
Authors: Yamasaki A. , Takeda M. , Yamauchi T. , Takada G. , Hattori S.
Published: July 2016

Variability of the light curves of the short-period eclipsing binary system GR Tau (, almost-contact binary) is studied. It is found that GR Tau experienced both the state which is characterized by asymmetric light curves and the state characterized by symmetrical light curves.
Magnetic Field Evolution in Accreting White Dwarfs
Authors: Cumming Andrew
Published: July 2016

I discuss the effect of accretion on the magnetic field of an accreting white dwarf. Whereas the magnetic fields of isolated white dwarfs are not expected to change significantly with time, I show that if an accreting white dwarf increases in mass at a rate > 1–5 × 10−10MΘ yr–1, accretion overcomes ohmic diffusion and has a significant effect on the field structure. I discuss the implications of this result for observed systems. In particular, accretion induced field evolution may provide the missing evolutionary link between the strong field, slowly accreting AM Her systems and the weak field, more rapidly accreting intermediate polars.
The Spin-Up Rate of the White Dwarf in GK Per
Authors: Mauche Christopher W.
Published: July 2016

We use hard X-ray light curves measured by the Chandra HETG and RXTE PCA during the late rise and plateau phases of the 2002 March–April outburst of the intermediate polar GK Per to determine that its X-ray pulse period P = 351.332 ± 0.002 s. Combined with previous X-ray and optical measurements of the spin period of the white dwarf, we find that its spin-up rate Ṗ = 0.00027 ± 0.00005 s yr−1.
High-Speed Imaging and Spectro-Polarimetry with Subaru Telescope
Authors: Sekiguchi Kazuhiro , Charles Phil , van Zyl Liza , Woodhouse Guy F.
Published: July 2016

We are developing a high-speed option for the Faint Object Camera and Spectrograph (FOCAS) at the Cassegrain focus of the Subaru 8.2 meter telescope at Mauna Kea, Hawaii. FOCAS has been used for direct imaging, low-dispersion multi-object spectroscopy, imaging polarimetry and spectro-polarimetry of faint objects. The high-speed option utilizes an EEV CCD47-20 with the frame transfer operation to achieve up to ~ 0.1 sec time resolution. This paper presents a summary of the expected capability and the implementation schedule.
The Spin Periods of Magnetic Cataclysmic Variables
Authors: Norton A. J. , Somerscales R. V. , Wynn G. A.
Published: July 2016

We have used a model of magnetic accretion to investigate the rotational equilibria of magnetic cataclysmic variables (MCVs). This has enabled us to derive a set of equilibrium spin periods as a function of orbital period and magnetic moment which we use to estimate the magnetic moments of all known intermediate polars. We further show how these equilibrium spin periods relate to the polar synchronisation condition and use these results to calculate the theoretical histogram describing the distribution of magnetic CVs as a function of Pspin/Porb. We demonstrate that this is in remarkable agreement with the observed distribution assuming that the number of systems as a function of white dwarf magnetic moment is distributed according to .
Blobby Accretion in Magnetic Cataclysmic Variables
Authors: Halevin A. V. , Andronov I. L. , Shakhovskoy N. M. , Kolesnikov S. V. , Ostrova N. I.
Published: July 2016

The processes of accretion of the gaseous blobs with different masses and densities onto strongly magnetized white dwarfs in the systems of polars have been modelled. We prove that shot noise in blue wavelengths represents accretion of the smaller and denser blobs than in redder wavelengths. Using combined “smooth particle hydrodynamics - drag force” model, we have predicted a shape of the accretion stream and active regions on the white dwarf surface.
Computational Models of the Accretion Stream in Polars
Authors: Cash Jennifer L.
Published: July 2016

I present the current results of my computational modeling of the accretion stream in polars. These numerical stream models, generated using an SPH code, yield a 3-dimensional map of the gas distribution throughout the stream, including the distribution of material as it impacts the white dwarf surface. The major features of the accretion streams generated by the model code are presented as well as results of a model representing EF Eri. The prospective future development of the model is also discussed.
Modeling the radio outbursts in AE Aquarii
Authors: Venter L. A. , Meintjies P. J.
Published: July 2016

In this paper we model the non-thermal radio to infra-red flares from AE Aqr. In our model the non-thermal flares originate in highly magnetized (Bblob ≥ 2000 G) blobs that may be among the propeller ejected outflow. It was shown that the condition ß ≤ 1 constrains the frozen-in magnetic field in these blobs to Bblob ≥ 2000 G, which is of the same order of magnitude as the inferred polar field of the secondary. As these magnetized blobs encounter the violent mhd-propeller, processes such as reconnection, magnetic pumping, and shocks will result in continuous acceleration of electrons from (γ = 2 → 30; δ = 2.8 → 2.6) with resultant synchrotron emission. The total radio to infra-red flare spectrum was modelled in terms of such expanding magnetized synchrotron emitting blobs in various stages of their evolution from ρ = (r/r°) = 1 → 400. In terms of our model, the total integrated flux during outbursts, over the wide frequency range from 1 GHz is the result of several (~ 20) synchrotron emitting blobs observed in different stages of their evolution, resulting in a spectrum showing a peak flux of Sv ~ 148 mJy at v ~ 1805 GHz (~ 166 microns), where the spectrum changes from a typical self-absorbed Sv ∝ vα spectrum to Sv ∝ v-(δ-1)/2 spectrum, i.e. where the blobs are combined optically thin.
White Dwarfs in Magnetic Cataclysmic Variables
Authors: Shylaja B. S.
Published: July 2016

An attempt has been made here to seek the origin of the magnetic white dwarfs in Cataclysmic Variables. Following the suggestion made in the case of isolated white dwarfs, we look at the possibility of binaries with magnetic A type stars known as chemically peculiar stars as progenitors of MCVs. The evolution of the binary is discussed and compared with the available statistics.
Dynamo-Induced Mass-Transfer Variations in MCVs
Authors: Hessman F. V.
Published: July 2016

The fully convective secondary stars in short-period CVs are rapidly rotating and thus should have a characteristic global magnetic field produced by an α2-Dynamo. This field is expected to be dipole-like, with an axis lying in the orbital plane, and to rotate slowly through the mass of the star on magnetic diffusion timescales of years to decades. When one of the poles of this field is near the inner Lagrange point, the reduction in the sound speed, scale-height and possibly the density in the giant “starspot” will modulate the mass-transfer to the primary. Given the extremely high Coriolis numbers (low Rosby numbers) of CV secondaries, this is a generic mechanism which is capable of explaining the extended high- and low-states in the mean light curves of shorter period MCVs and perhaps the lightcurves of non-magnetic CVs (where a disk may make it difficult to see this effect). The diffusion timescale and hence the period of rotation of the field within the secondary is of order the synchronization timescale, so shorter period polar’s are unlikely to be in rotational equilibrium.
Magnetic Cataclysmic Variables: a Summary
Authors: Lasota Jean-Pierre
Published: July 2016

This is a short summary of the main problems presented and discussed at the Cape Town conference.
Earth’s Rotation and Polar Motion Based on Global Positioning System Satellite Data
Authors: Anderle R. J. , Beuglass L. K. , Carr J. T.
Published: July 2016

Using current procedures, polar motion and Earth’s rotation can be computed from 7 days of observations from four stations to four Global Positioning System Satellites to an accuracy of 1.5 m and .3 msec/day, respectively. Improved computational techniques or instrument accuracy and/or measurements from additional satellites or stations would give significant improvements in accuracy.
Is the Gravitational Constant Changing?
Authors: Van Flandern T. C.
Published: July 2016

The question posed by the title is not yet conclusively resolved. Nonetheless, determinations of the lunar tidal acceleration based on dynamical time scales are now in reasonable accord with one another, whether based on the transits of Mercury, ancient eclipse observations, ocean tide models, or artificial satellite observations; these give a purely tidal component of −28.8 ± 1.5 “/cy2. Lunar occultations and laser ranging now give concordant results for the total anomalous acceleration of about −22.8 ± 1.5. The difference in these results gives an acceleration of possible cosmological origin of ṅ/n = +3.5 ± 1.2 × 10−11 per year, which is also consistent with very preliminary planetary radar studies. If interpreted in the scalar covariant cosmology of Canuto and Hsieh, this implies that Ġ/G = (−6.9 ± 2.4) × 10−11 per year, if measured in atomic time, but zero if measured in dynamical time. The implications for relativity and cosmology are discussed briefly in the paper, scheduled for the Astrophysical Journal issue of 1 September 1981.
A New Dimension to Retrieval
Authors: Collins Mike J.
Published: July 2016

Searching in online databases for specific numerical data and for chemicals by formulae has always been difficult or, at best, complex. Two new additional indexing services were introduced to the INSPEC database at the beginning of 1987 to overcome these problems: Chemical Indexing - for searching all kinds of inorganic compounds and material systems, and Numerical Data Indexing - for limiting searches to a specific value or range of values of a particular physical quantity. The literature of SN 1987A, the first supernova to be discovered in 1987, is used to demonstrate the powers of these new indexing tools and how they compliment traditional retrieval aids such as classification, descriptors, and identifiers.
Simbad Bibliography and Other Astronomical Bibliographies
Authors: Dubois P.
Published: July 2016

Simbad is an astronomical database which includes bibliographical references. Some comparisons are made with other general or specialized astronomical bibliographies.
Use of Computers to Improve Library Services at the Space Telescope Science Institute
Authors: Stevens-Rayburn Sarah
Published: July 2016

There is a wonderful scene near the end of Frank Baum’s The Wizard of Oz wherein the curtain hiding the wizard is suddenly whipped back and the wizard is exposed as a mere mortal, pushing buttons to make things happen, mostly through illusion. I often think my library users would have the same shock as Dorothy and her friends if they took the time to find out how we go about providing them with information. They’d whip back the curtain and find me madly pushing keys on the terminal, shouting “Ignore that woman over there!” This talk is supposed to be on the use of computers in astronomy libraries or at least in one astronomy library — and it is, but it also about providing an information service when you have only a modicum of information and a great demand for service. Since the Institute library has been in existence for only five years and because of the enormously transitory nature of much of astronomy publishing, we have remarkably little available in-house, particularly of the historical material. That’s where the creativity of a wizard (or the computer of the librarian) comes in. We may not have a specific item or we may not have the item exactly as requested, but we know who does and we use any and every means possible to obtain the item quickly. We concentrate on providing the specific information needed even if the user is unaware that what was requested may be available in ways other than that suggested in the request. (My favorite example of this phenomenon is the one pointed out by D.A. Kemp of a paper that appeared in five different series plus twice in report form.)
Introduction to the Issues
Authors: Crawford David L.
Published: July 2016

Astronomy is facing a present and future severe problem with adverse environmental impact, just as is the rest of mankind. While we all suffer from air and water pollution, amateur and professional astronomers are finding the universe disappearing from view, due to light pollution, radio interference, and space junk. We must build awareness of these issues and seek solutions.
Impact of Outdoor Lighting on Moths
Authors: Frank Kenneth D.
Published: July 2016

Outdoor lighting incapacitates and destroys some moths. It disturbs flight, navigation, vision, migration, dispersal, oviposition, mating, feeding, and crypsis. It may also snift circadian rhythms. Lamps may incinerate or desiccate moths, or lead to moth’s destruction by birds, bats, spider, and vehicular traffic. Conservation efforts need to consider disruptive ecological effects of outdoor lighting. Low pressure sodium lamps may reduce these effects.
A System Simulation Approach for the Control of Stray Electric Light
Authors: McGowan T.K. , Hibbs J.
Published: July 2016

There are practical ways to improve the way lighting systems are designed and operated where the objective is to control stray light from the astronomical (or other) point of view. Most efforts, however, have been direct toward the lighting hardware or operation on a micro level.
City of Portland Conversion to Cut-off Fixtures
Authors: Hughes William A.
Published: July 2016

In 1980, the City of Portland began a conversion project to change out all existing mercury vapor street lights to high pressure sodium. During the planning and design portion of the project, the City hired a consulting firm to look at our existing system and make recommendations as to light source and fixture configuration. After some on site studies of existing street lighting, it was recommended that all arterial streets of the City of Portland be converted from mercury vapor to high pressure cut-off fixtures, in order to cut down glare in the eyes of drivers. Secondly, it was recommended that, on arterial streets, the City could no longer afford to light “key-hole to key-hole.” It was important to confine the light to the street right-of-way.
Observations of Space Debris
Authors: Taff L. G.
Published: July 2016

Optical observations of near Earth and deep-space debris conducted at M.I.T.’s artificial satellite observatory will be discussed. A brief review of observing technique, regions of high debris density, and amount of debris in orbit will be given. The unique, duplex facilities of the observatory allow the discrimination of debris from meteors, the construction of an orbital element set, and real-time identification of cataloged artificial satellites. Near-Earth debris is present in large numbers in all the popular near-Earth orbits; at least 5-6 times the 5000-6000 objects in the NORAD catalog. In deep-space, the new presence of Ariane-related debris adds significantly to the existing population which is treble that cataloged by NORAD.
Electronic Smog in Europe
Authors: Kahlmann H.C.
Published: July 2016

With so many satellites (current and anticipated) broadcasting all sorts of signals in all sorts of bands, a group of radio astronomers came together in 1987 to discuss the problems. This group has become the European Science Foundation Committee on Radio Astronomical Frequencies (ESF-CRAF). The terms of reference of this Committee, together with its future activities and possibilities within the European legal context were discussed in the oral paper.
Estimating Harmful Levels of Radio-Frequency Radiation
Authors: Crane Patrick C. , Hillenbrand Lynne A.
Published: July 2016

Determining whether a particular radio transmitter will produce harmful levels of radio-frequency radiation at a location of interest (the “receiver,” be it a nearby home or a distant radio telescope), has two steps. The first is to determine which standard for harm applies: Section II reviews those for human exposure, for interference with electronic devices, for interference with optical and infrared astronomy, and for interference with radio astronomy.

The second step is to estimate the propagation losses between the transmitter and the “receiver.” Many factors, several highly time variable, contribute to such losses - including atmospheric refraction, diffraction by obstacles, tropospheric scattering, and atmospheric absorption - and are discussed in Section III.
Radio Astronomy and the CCIR
Authors: Pankonin Vernon
Published: July 2016

The International Radio Consultative Committee (CCIR) is a permanent organization within the International Telecommunication Union (ITU). The purpose of the CCIR is to provide technical advice to the ITU and its various organs and members on the characteristics of the radio services which are governed by the International Radio Regulations, a product of the ITU. This is accomplished through reports and recommendations which may result from the regularly scheduled meetings of the CCIR or from meetings convened to prepare for a special event such as an upcoming World Administrative Radio Conference (WARC). The CCIR is divided into Study Groups. Study Group 2 covers Space Research and Radioastronomy. This paper describes the interactions of radio astronomers with Study Group 2. The radio astronomy related Study Questions currently before this Study Group are delineated, and the nature of the active reports and recommendations are discussed.
Heat Pollution by Large Buildings and the Effects upon Astrometric Observations
Authors: Hughes James A. , Kodres Calvin A.
Published: July 2016

Recent, large scale, real estate development near the U.S. Naval Observatory has led to an investigation of the systematic atmospheric effects which heat from large buildings can cause. Results show that non-negligible slopes of the atmospheric layers can be induced which cause a surprisingly large anomalous refraction. The Navier-Stokes equations were numerically integrated using the appropriate boundary conditions and the resulting isopycnic tilts using the appropriate boundary conditions and the resulting isopycnic tilts charted. Rays were then essentially traced through the perturbed atmosphere to determine the magnitude of the anomalous refraction.
The distribution of types of Luminous Blue Variables
Authors: Bohannan Bruce
Published: July 2016

If Luminous Blue Variables (LBVs) are not each unique types, three broad groups can be characterized depending on the luminosity and location ofLBVsin the Hertzsprung-Russell diagram. To assist in defining the evolutionary nature ofLBVs, connections are made to stars that have similar spectral character with the suggestion that some of these objects that may someday becomeLBVs.
The wind of P Cygni
Authors: Puls J. , Pauldrach A.W.A. , Kudritzki R.P.
Published: July 2016

The stationary features of the wind of P Cygni are considerably different from those of ‘normal’ supergiant winds with comparable luminosity. In contrast to such winds, which are generally accepted to be driven by radiation pressure, P Cygni’s mass-loss rate is higher by a factor of 5, the terminal velocity is higher by a factor of 10, and the velocity law itself is much flatter than would be expected from a first glance at glance at typical scaling relations. However, these relations depend crucially and non-linearly on the star’s distance from the Eddington limit, which for P Cyg is very small (see below). Here we investigate whether the acceleration mechanism of P Cygni’s wind can also be explained by line pressure and to what extent self-consistent wind models represent the observed quantities (especially the IR energy distribution).
The optical micro-variations of the S Dor-type stars AG Car and HR Car
Authors: van Genderen A.M. , Thé P.S. , Heemskerk M. , Heynderickx D. , Larsen I. , Wanders I. , van Weeren N.
Published: July 2016

VBLUW photometry of high precision of two S Dor type stars AG Car (in a quiescent stage) and HR Car was made in 1987 and 1988. Both stars show visual micro variations with amplitudes of 0m.1 – 0m.2 with time scales– 10dfor AG Car and– 20dfor HR Car.
Atmospheric parameters and accelerations in the outer parts of luminous hot stars
Authors: Nieuwenhuijzen Hans , Jager Cornells de
Published: July 2016

In the atmospheres of the most extreme luminous stars, close to the Humphreys-Davidson limit, the inward gravitational acceleration is for a great part compensated by outward accelerations due to radiation pressure, turbulent pressure and dynamic pressure of the stellar winds. As a result the effective acceleration is very small, resulting in blown-up atmospheres that can no longer be considered plane-parallel or in hydrostatic equilibrium.
A Multi-Frequency Study of the Peculiar Interacting System ARP 206
Authors: Noreau Louis , Kronberg Philipp P.
Published: July 2016

Arp 206 is a nearby (7.8 Mpc), relatively large (7′.5 x 2′.0), and bright ( = 11.07) interacting system comprising unequal members: NGC 3432 and UGC 5983. A third anonymous galaxy, “Arp 206c”, is visible in the field, (see Figure la) Vorontsov-Velyaminov (1959) included the NGC 3432-UGC 5983 pair in his Atlas and Catalogue of Interacting Galaxies (VV-11). On the other hand Arp (1966) interpreted the system as a galaxy with material ejected from the nucleus (Arp 206).

Bertola (1966, 1968, and priv. comm.) obtained long-slit spectra of the largest galaxy of the pair, NGC 3432. This showed strong non-circular motions that could be interpreted as an explosion in its nucleus. This work is in line with a similar study of another system, Arp 205 (Bertola et al. 1983, Noreau and Kronberg 1986, 1987). In this first case it was found that the non-circular radial velocities were caused by the ‘re-entry’ of galactic material torn away by the interacting system.
VLA Neutral Hydrogen Imaging of Compact Groups
Authors: Williams B. A. , McMahon P. M. , van Gorkom J. H.
Published: July 2016

We present images of the neutral hydrogen (H I) in the direction of the compact groups of galaxies, HCG 31, HCG 44, and HCG 79. We find in HCG 31 and HCG 79, emission contained within a cloud much larger than the galaxies as well as the entire group. The H I emission associated with HCG 44 is located within the individual galaxies but shows definite signs of tidal interactions. We have imaged the distribution and kinematics of neutral hydrogen at the two extremes of group sizes represented in Hickson’s sample. HCG 44 is at the upper limit while HCG 18, HCG 31, and HCG 79 are at the lower end. Although the number of groups that have been imaged is still very small, there may be a pattern emerging which describes the H I morphology of compact groups. The true nature of compact groups has been the subject of considerable debate and controversy. The most recent observational and theoretical evidence strongly suggest that compact groups are physically dense, dynamical systems that are in the process of merging into a single object (Williams and Rood 1987, Hickson and Rood 1988, Barnes 1989). The neutral hydrogen deficiency observed by Williams and Rood (1987) is consistent with a model in which frequent galactic collisions and interactions have heated some of the gas during the short lifetime of the group. The H I disks which are normally more extended than the luminous ones are expected to be more sensitive to collisions and to trace the galaxy’s response to recent interactions. Very Large Array observations can provide in most cases the spatial resolution needed to confirm the dynamical interactions in these systems.
Correlation Functions for Pairs and Groups of Galaxies
Authors: Kalinkov M. , Kuneva I.
Published: July 2016

There are many studies on the correlation functions of galaxies, of clusters of galaxies, even of superclusters (e.g. Groth and Peebles 1977; Davies and Peebles 1983; Kalinkov and Kuneva 1985, 1986; Bahcall 1988 and references therein) but not so many on pairs and groups of galaxies.
The Complex Nature of the Seyfert Galaxy NGC 7592
Authors: Rafanelli Piero , Marziani Paolo
Published: July 2016

NGC 7592 = VV 731 = MCG-01-59-017 is a system of close interacting galaxies. Two main galactic bodies are present in the CCD R-band image taken at the 1.8m, F/9 telescope of the Asiago Observatory and shown in Figure 1:

• a north-western (NW) component (≡VV 731B), whose starlike nucleus (A) shows a Seyfert-type spectrum (Archipova et al., 1981). A is surrounded by a nearly spheroidal envelope, with an extension in the west at P.A. = 290° detected up to a distance from A of ≈ 9 arcsec, which corresponds to ≈ 2.5h-1kpc of projected linear distance (1 arcsec ≈ .35 h-1kpc at the redshift z = 0.0244; H0 = 100 h km s-1Mpc-1). This extension seems to bend in the northern direction and to join a bright wing, detected up to « 22 arcsec from A, which turns to east and resembles a spiral arm or a tidal tail.

• The envelope around A is connected (over ~ 20 arcsec 7h-1kpc) to a second galactic body (SE) located in the south-east of it. Its nucleus (B), identified by Markarian and Lipovetskii (1976) as the nucleus of Mkn 928, is located at dAB ~ 11 arcsec(~ 4h-1kpc) from A at P.A. = 100°. The morphology of this component is highly peculiar. In the central region, B is linked to two fainter knots which extend up to d″ ~ 4 arcsec at P.A. — 90°. This structure gives to the region surrounding B an elongated and distorted shape. Moreover, a bar-like structure is detected on either sides of B. The north-eastern side of the bar (P.A. = 40°) joins a slightly distorted loop of condensations, which can be traced from P.A. = 335° (at a distance from B«6 arcsec % 2.1 h-1kpc) to P.A. = 100° and from P.A. = 200° to P.A. = 240°, but not in corrispondence of the contact region between the two galaxies. This structure seems to be drained and distorted in the direction of a third condensation C at dBC ≈ 11.7 arcsec (≈ 4.1 h-1kpc) from B at P.A. — 212°. A faint plume bent in a direction opposite to that expected for spiral arms of the SE galaxy appears to extend from the west side of C.
Global Effects of Interactions on Galaxy Evolution
Authors: Kennicutt Robert C.
Published: July 2016

Recent observations of the evolutionary properties of paired and interacting galaxies are reviewed, with special emphasis on their global emission properties and star formation rates. Data at several wavelengths provide strong confirmation of the hypothesis, proposed originally by Larson and Tinsley, that interactions trigger global bursts of star formation in galaxies. The nature and properties of the starbursts, and their overall role in galactic evolution will also be discussed.
A Dynamical Proximity Analysis of Interacting Galaxy Pairs
Authors: Chatterjee Tapan K.
Published: July 2016

Using the impulsive approximation to study the velocity changes of stars during disk-sphere collisions and a method due to Bottlinger to study the post collision orbits of stars, the formation of various types of interacting galaxies is studied as a function of the distance of closest approach between the two galaxies.
Explaining Compact Groups as Chance Alignments
Authors: Mamon Gary A.
Published: July 2016

The physical nature of the apparently densest groups of galaxies, known as compact groups is a topic of some recent controversy, despite the detailed observations (Hickson, in these proceedings, and references therein) of a well-defined catalog of 100 isolated compact groups compiled by Hickson (1982). Whereas many authors have espoused the view that compact groups are bound systems, typically as dense as they appear in projection on the sky (e.g., Williams & Rood 1987; Sulentic 1987; Hickson & Rood 1988), others see them as the result of chance configurations within larger systems, either in ID (chance alignments: Mamon 1986; Walke & Mamon 1989), or in 3D (transient cores: Rose 1979). As outlined in the companion review to this contribution (Mamon, in these proceedings), the implication of Hickson’s compact groups (hereafter, HCGs) being dense bound systems is that they would then constitute the densest isolated systems of galaxies in the Universe and the privileged site for galaxy interactions.
Typical Motions in Multiple Systems
Authors: Anosova Joanna
Published: July 2016

In very old times, people counted – one, two, many. I want to show you now that they were right.

Let’s consider the motions of isolated bodies:

1. N = 1 - simple motion;

2. N = 2 - Keplerian orbits;

3. N = 3 - this is the difficult problem. In general, this problem can be studied only by computer simulations.
Gas Flows in S-E Binary Systems of Galaxies
Authors: Sotnikova N. Ya.
Published: July 2016

Tidal interaction between the galaxies in binary systems leads to important consequences. Some peculiarities in galactic morphology as well as the transfer of matter from one galaxy to another may be due to this factor. In particular, gas flows in intergalactic space may be formed. Such flows enriching one component with gas from the other may play a substantial role in the evolution of mixed (S-E) pairs. One can mention several facts corroborating the possibility of the gas transfer from the spiral to the elliptical galaxy.
Multiplicity Among the Young Stars
Authors: Simon M.
Published: July 2016

Our survey for companions of the young stars now includes 45 systems in the Taurus star-forming region (SFR) and 21 in the Ophiuchus SFR. It is carried out by lunar occultation and imaging in the IR and can identify binaries in the separation range 0″.005 to 10″ in systems brighter than K=10 mag. The observed multiplicity in Taurus is ~1.6 stars/system which is comparable to that of the nearby solarlike stars but corrections for incompleteness increase the multiplicity to at least 1.8.

Inner active disks are equally represented among the single and multiple systems. The multiple systems have less massive outer disks than the single systems, but there are significant exceptions. The binary UZ Tau W contains a circumstellar disk or disks of mass ~0.024 M⊙ and size ~13 AU. The quadruple GG Tau system has a remarkably extensive circumbinary disk of mass ~ 0.07M⊙. These mass estimates are comparable to the minimum values required for the proto-planetary disk of the Solar System.

The specific angular momenta of the most widely spaced binaries in our sample adjoin the lowest values that can be measured for molecular cloud cores. The actual distributions probably overlap which suggests that the origin of the angular momentum of binaries is in their molecular cloud birthplaces.
Orbital Circularization in Binaries with A-Type Primary Stars
Authors: Matthews Lynn D. , Mathieu Robert D.
Published: July 2016

It has long been recognized that tidal interaction between the components of close binaries will tend to circularize their orbits (e.g., Darwin 1879; Zahn 1977). In fact observations show an abundance of circular orbits in binaries with periods of days. However, the dissipation mechanism required for circularization, the timescales involved, and the dependence on period, mass, evolutionary state, and initial eccentricity of the system remain subjects of debate.

Circularization theories such as Zahn (1977) state that circularization in binaries where at least one component possesses a convective envelope is much more efficient than in binaries where both stars have radiative envelopes. Giuiricin et al. (1984; GMM) studied the period-eccentricity distribution of O-, B- and A-type binaries and argued that the observations were consistent with Zahn’s theory for radiative envelopes. But recently, Tassoul (1988) has presented an alternative circularization theory with similarly efficient circularization in radiative- and convective-envelope binaries. In addition, period-eccentricity distributions for many samples of main-sequence convective-envelope binaries are now available. Here we reconsider the observed short-period eccentricity distribution of radiative-envelope binaries in light of these new observations and theory. Specifically, we investigate the period-eccentricity distribution of a sample of binaries with A-type primary stars.
Databases of Interest to Double– and Multiple–Star Observers
Authors: Warren Wayne H.
Published: July 2016

A large collection of machine–readable catalogs containing data for various types of double– and multiple–star systems has become available over the last decade or so. These catalogs can be divided logically into general compilations of multiple–star data for visual systems and other collections of information for particular classes of binaries, such as cataclysmic, eclipsing, interferometric, spectroscopic, etc. A few large databases containing double– and multiple–star data have also become accessible over the last few years. This paper gives a general overview of some of the more important machine–readable catalogs and databases available, and includes a brief description of the information that each contains. The potential for what can become available in the near future, just by incorporating current information into a system providing full data retrieval, is also discussed.
Differential Photometry of Binary Stars
Authors: Dick J.S.B. , Devaney M.N. , Jones D.H.P. , ARGYLE R.W.
Published: July 2016

Using a short exposure, one dimensional area scanner, a programme of photometry on binary stars with separations <10″ has been initiated; using speckle techniques, photometry of binaries with separations <1″ is possible. We describe the equipment and techniques and present results acquired during commissioning.
Zeta Cancri
Authors: Harrington Robert S. , Douglass Geoffery G. , Worley Charles E.
Published: July 2016

Zeta Cancri is a multiple system in which the well-observed orbit is an inner, or close one. Three-body coupling effects are an order of magnitude more significant for the close orbit in a hierarchical system, and they must be included. An exact numerical integration is very easy and requires no approximations. Inclusion of these effects improves the residuals for this system.
A CCD Optical Search for Visual Very Low–Mass Companions of Halo Stars
Authors: Martin Eduardo L. , Rebolo Rafael
Published: July 2016

We have begun a search for faint companions to cataloged G/K metal–deficient dwarfs. The main goals of this investigation are:

i)

to collect a database of halo M-type stars

ii)

to study the frecuency of binary separations in the range 1″ - 50″ for Population II stars

iii)

to find some metal-poor very–cool dwarfs that may serve as references to investigate the low-mass end of the halo main sequence.

In this paper we present the first results from VRI CCD photometry of a subset (51 stars) of our sample. We have identified 7 possible very low mass companions (angular separations 1″.5 – 30″) of halo subdwarfs with [Fe/H] in the range from −0.8 to −2.6.
Strømgren Photometry of Wide Visual Double Stars with G–Type Primaries, Most of Which Have Common Origin Components
Authors: Sinachopoulos D. , Van Dessel E.
Published: July 2016

We have performed uvby aperture photometry of wide visual double stars with G–type primaries. We chose our pairs in order to have minimum angular separation of their components 10″ and mainly less than 20″. It is shown that both components have similar photometric parameters. We infer that most of these double stars have components of common origin.
Photometric Systems
Authors: Bessell Michael S.
Published: July 2016

Multicolour photometry has historically been carried out within a variety of standard systems. With the advent of new detectors with different wavelength sensitivities to those of the original system and the use of subsets of secondary standards, many subtle and not so subtle changes have occurred to the original systems. However, by reverse engineering, the passbands of the modified standard systems can be determined which enables good realisation of theoretical colours and better passband matching for CCD-based photometry. In this paper, the various photometric systems will be discussed and compared and strategies will be outlined for ensuring that precise relative photometry is maintained in the future, in particular from area detectors.
Vilnius Photometry in the Southern Hemisphere
Authors: Dodd R.J. , Forbes M.C. , Sullivan D.J.
Published: July 2016

The seven intermediate passband filters of the Vilnius photometric system enable a more comprehensive and discriminating classification of stellar objects than is possible in broadband systems. To date, a lack of suitable standard stars has inhibited its use in the Southern Hemisphere. We have an established programme for extending the network of northern Vilnius standards into the southern skies. This paper briefly summarizes the characteristics of the Vilnius system, provides a synopsis of the data obtained on over 200 standard stars so far and presents preliminary CM and CC diagrams for the open cluster Omicron Velorum (IC2391).
Absolute Spectrally Continuous Stellar Irradiance Calibration in the Infrared
Authors: Cohen Martin , Walker R.G. , Barlow M.J. , Deacon J.R. , Witteborn F.C. , Carbon D.F. , Augason G.C.
Published: July 2016

We present first efforts to establish a network of absolutely calibrated continuous infrared spectra of standard stars across the 1-35μm range in order to calibrate arbitrary broad and narrow passbands and low-resolution spectrometers from ground-based, airborne, balloon, and satellite-borne sensors. The value to photometry of such calibrated continuous spectra is that one can integrate arbitrary filters over the spectra and derive the stellar in-band flux, monochromatic flux density, and hence the magnitude, for any site. This work is based on new models of Sirius and Vega by Kurucz which were calculated by him, for the first time, with realistic stellar metallicities and a customized finely-gridded infrared wavelength scale. We have absolutely calibrated these two spectra and have calculated monochromatic flux densities for both stars, and isophotal wavelengths, for a number of infrared filters. Preliminarily, the current IRAS point source flux calibration is too high by 2, 6, 3, and 12% at 12, 25, 60, and 100μm, respectively.
CCD Standard Fields
Authors: Jones D.H.P.
Published: July 2016

There are several standard fields for CCDs available in the literature. Some of these have been observed many times with the CCD cameras of the Isaac Newton Group of Telescopes on La Palma. These observations were made in order to establish the zero-points and colour equations for the U BV RI filters. Now that many observations are available in the data archive it is possible to combine them and search for inconsistencies in the published magnitudes and colours. This discussion will lead to standard fields of a higher quality. Furthermore astrometric plates have been taken of several of these fields which will be used to provide accurate positions as well as magnitudes and colours. These will provide the scale, orientation and distortion of any CCD camera.
High-Precision Photometry
Authors: Young A.T.
Published: July 2016

The current precision of differential comparisons, within a fixed instrumental system, reaches about a millimagnitude. The current accuracy of transformations between systems is on the order of 0.01 mag, but is worse in some cases. The transformation errors are due to mis-matches between instrumental and standard systems, and cannot be transformed away without further information. A simple geometric model is proposed, which illuminates the transformation problem, and suggests means of minimizing it. Misplaced band edges are the main cause; tighter specifications on filters will help to reduce these errors. The ultimate solution is to use sampled systems in which some bands look like the derivatives of their neighbors. This automatically produces enough band overlap to comply reasonably well with the sampling theorem.
Problems of CCD flat fielding
Authors: Tobin William
Published: July 2016

CCD flat fielding using an illuminated dome screen is discussed. Rings of reduced response caused by dust specks on the cryostat entrance window indicate the required uniformity of screen illumination but may not divide satisfactorily because of telescope flexure. Illumination colour is important for shorter-wavelength, broad-band filters. Flat fields can be distorted significantly by light scattered off telescope baffles. Special precautions are needed for uv flat fielding. The Mt John TH 7882 CDA chip is slightly sensitive to polarisation. Dome flat-fielding accuracy of 0.3% would seem achievable.
Searching for Type la Supernova Progenitors
Authors: Renzini Alvio
Published: July 2016

The status for the identification of specific astronomical objects as SNIa progenitors is reviewed. Single or double degenerate progenitors? Chandrasekhar or sub-Chandrasekhar mass exploders? These are the two main questions still to be answered concerning the progenitors of Type la supernovae. Although all four combinations may be represented in nature, searches for double degenerates seem to indicate that such systems provide a minor channel for the production of SNIa’s. The more promising candidates appear to be symbiotic stars, consisting of a single degenerate star and a sub-Chandrasekhar mass star.
The Oxygen 1.13 μm Fluorescence Line of SN1987A: a Diagnostic for the Ejecta of Hydrogen-Rich Supernovae
Authors: Oliva Ernesto
Published: July 2016

The bright O I λ11287 line observed in SN1987A is produced by the Bowen fluorescence with Lyβ and comes from regions that lie within a Sobolev length (δR ∼ 10-3RSN, the maximum distance over which fluorescence can work) from hydrogen rich gas ionized by the 56Co decay. Its strength relative to hydrogen lines (e.g. Brγ) depends on the O/H relative abundance in the ‘fluorescent region’ and on the density (i.e. the filling factor) of the gas. The observed evolution of λ11287 can be successfully understood using a relatively simple theory which takes into account the effects of transfer in the O I lines and is the generalization of the classical theory of Bowen fluorescence.
Interaction of supernova ejecta with circumstellar matter and X-ray emission: SN 1987A & SN 1993J
Authors: Suzuki T. , Nomoto K. , Shigeyama T. , Kumagai S.
Published: July 2016

We perform hydrodynamical calculations of the collision between the supernova ejecta and circumstellar matter for SN 1987A and SN 1993J. For SN 1987A we predict light curves of X-ray emissions from the shocked ring. For SN 1993J, thermal X-rays from the shocked circumstellar matter can consistently account for the observations with ROSAT, ASCA, and OSSE.
Compact Objects in Supernova Remnants
Authors: Chevalier Roger A.
Published: July 2016

Core collapse in very massive stars can lead to a central black hole that swallows the rest of the star and in less massive stars to a central neutron star and explosion. There is probably an intermediate mass range that gives an explosion and a central black hole; supernova remnants with no observable central object are candidates. The association of pulsars with Type II supernovae gives an estimate of the pulsar power to be expected in a supernova, but the uncertainty in the initial pulsar periods gives a wide range in possible powers. The relativistic wind bubble model for the Crab Nebula has steadily developed and there are now predictions regarding particle acceleration in the optical wisps. The bubble model with expansion into supernova gas can also be applied to other young pulsar nebulae.