bluuebunny/crossref_metadata_2025_split huggingface dataset:
Facts on space epoch versus two-century-old paradigm
Authors: Drobyshevski E.M. 
Published: July 2016

AbstractThe Kant-Laplace nebular paradigm of the origin of the Solar System fails to predict, and even inadequately interprets, observations made in the space era. In each case it has had to invoke additional hypotheses. Our paradigm considers the Solar System within present-day approach to the origin of multiple stellar systems. The Jupiter-Sun system is considered as the limiting case of a close binary, where a multiplicity of planets form on a short time scale within a rapidly rotating proto-Jupiter, a very dense analog of classical protoplanetary discs. The numerous problems associated with the origin, evolution, and manifestations of the minor bodies can be solved within the framework of their New Explosive Cosmogony. It is based on the single assumption of a buildup, in the form of a solid solution in ice, of large amounts of 2H2+O2generated in volume electrolysis of dirty ices in the massive envelopes of Ganymede-type bodies. An explosion of a body with anM&lt;0.5Moonsheds off completely its envelope. It is such an event that happened 3.9Byrago, followed by collisional evolution, which formed apparently the MB asteroids. The explosion of a body withM &gt; 1Moonremoves only a part of its matter in the form of water vapor and organics present in the ices, mineral particles, and large fragments of the outermost ice layers, which also contain 2H2+O2. These are the nuclei of SP comets, and their material is also capable of combustion or detonation under certain conditions. The ice explosions of Titan (only ∼104yrago), of the Galilean satellites, and of their fragments can account both for many of their properties and for the origin of the irregular satellites and Trojans, as well as for the sources of some SP and LP comets. Some of the predictions made on this basis have been confirmed.
Multi-Wavelength Observations of Stellar Flares
Authors: Byrne P. B. 
Published: July 2016

AbstractWe present observational data on stellar flares from a range of wavelength regimes, many of which were obtained simultaneously. Physical parameters of these flares are derived and discussed in the framework of the general solar flare model. It is found that flares on dMe stars are solar-like, except in mean energy. The parameters of flares on RS CVn stars are more extreme, however, and may require new models for their interpretation.
A Review of Stellar Flares and Their Characteristics
Authors: Pettersen B. R. 
Published: July 2016

AbstractWe review the flaring activity of stars across the HR-diagram. Brightenings have been reported along the entire Main Sequence and in many stars off the Main Sequence. Some stars are decidedly young, others are in advanced stages of stellar evolution. Flares are common on stars with outer convection zones and outbursts have been reported also on other types of stars, although confirmations are needed for some of them.Analyses of flare occurrence sometimes find flares to be randomly distributed in time, and sometimes indicate a tendency for flares to come in groups. Preferred active longitudes have been suggested. Recent solar results, where the occurrence rate for flares is found to exhibit a periodicity of 152 days, suggest that stellar flare data should be reanalyzed over long time baselines to see if the present confusing situation can be resolved.The radiation from stellar flares is dominated by continuum emission and about equal amounts of energy have been recorded in the optical, UV, and X-ray regions of the spectrum. In solar flares strong continuum emission is rarely recorded and a large collection of bright emission lines takes prominence. Small flares occur more frequently than large ones and the latter have longer time-scales. Flare energies can exceed 1037 erg. The most productive flare stars are those where the convective envelopes occupy large volumes. Slow stellar rotation rates are believed to reduce the level when the star has been braked significantly from its young rotation rate.
Some Applications of Small Computers to Optical Spectroscopy
Authors: Robinson Lloyd B. 
Published: July 2016

At Lick Observatory we have begun to use small computers as a basic element of some electronic instrumentation systems. It is felt that computer technology has advanced to the point where the results are likely to repay the investment. In our approach and choice of machine, we have tried to benefit by the experience gained over the past several years by nuclear physicists in nuclear spectroscopy applications.The major factor involved in choosing a small computer is probably one of economics. The initial cost is important, but, equally important, the costs of maintenance, programming, and the connection of peripheral equipment must be considered. A computer is sufficiently complex to require at least one person in an organization to spend considerable time familiarizing himself with the details of the machine. These extra costs, required to realize the potential of any computer system, are likely to exceed the initial purchase price of the system! It is important to take such factors into account when choosing a machine.
Period and Period Changes of RR Lyrae Variables in M15
Authors: Wesselink A. J. 
Published: July 2016

AbstractNew observations of the variables in M15 have been made with the Yale 40-in. reflector for the study of periods and period changes.Since the counting of cycles from the time of Bailey’s observations to the present day cannot always be made unambiguously, there is a corresponding uncertainty in the nature and amount of the period changes. Good lightcurves are obtained even when the periods used for their reduction are incorrect because the number of cycles in a day, or in a month, or in a year, is wrong by one. When this happens, however, period changes are likely to be indicated, and these will be spurious.Nevertheless, it can be shown that the periods of most variables have not been constant during the interval 1900–1970.The situation could be improved if a relatively small number of plates were to be obtained each year for several decades, preferably with the same instrument. Individual accuracy could be improved by the use of the electronic camera.The full contents of this paper will be published elsewhere.
The program of observation of minor planets and comets at the Bucharest Observatory
Authors: Cristescu Cornelia 
Published: July 2016

The observation of minor planets and comets began at the Bucharest Observatory in 1930, using the refracting telescope Merz—Prin (D = 38 cm, F = 600 cm). The observations were interrupted during the Second World War, and only in 1951 the department of photographic astrometry, much more developed, resumed the work.The program was devoted to the observation of comets and minor planets, the maximum magnitude obtained being 12 for minor planets and 9 for comets. Beginning from 1954 the Bucharest Observatory participates in the observation of the 10 minor planets, selected for the Catalogue of Faint Stars, and up to the end of 1970 about 4000 precise positions were obtained. At the request of the Institute of Theoretical Astronomy from Leningrad, these observations are continued. Besides these, about 1000 precise positions for other minor planets were obtained in the interval 1951—1963.
Optical Flares: Observations and Interpretations
Authors: Mirzoyan L.V. 
Published: July 2016

AbstractObservational results on flare stars in the Galaxy and their interpretation, based on the observational approach to early stages of stellar evolution at Byurakan, are considered. The evolutionary path of red flare stars is determined. Stellar flare activity is explained as an internal phenomenon of stars. The significance of photographic observations of stellar flares in star clusters and associations is emphasized.
Short-Time Flare Events of EV Lac
Authors: Zhilyaev B.E. , Verlyuk I.A. 
Published: July 2016

Moffett (1972) pointed out the existence of short-time outbursts in flare stars as long ago as 1972. Gershberg & Petrov (1986) had registered a flare in EV Lac with a duration of 28.4 and an amplitude of 38.4 in 1984 with ASTRON. In recent years, a few reports appeared about observations of short-time outbursts in EV Lac with a duration in the range from 08.1 to several seconds. These results were summarized briefly by Zhilyaev (1993). Our observations confirm the existence of short-time flare activity on EV Lac.The observations reported here were obtained at the 60 cm telescope at the Peak Terskol high-altitude Observatory (3 100 m above sea level) with a highspeed two-channel photometer (Zhilyaev et al. 1992) in B as well as simultaneously in both, U and V bands, with a time resolution down to 08.1. A new prefiltering technique (Zhilyaev 1995) has been used for the detection of smallscale activity of the flare star EV Lac.
Flares And Flashes: The Future
Authors: Vanderspek R. , Duerbeck H.W. , Fishman G.J. , Greiner J. , Hudec R. , Merck M. , Poveda A. , Samus N.N. , Seitter W.C. , Vanderspek R. , van Paradijs J. , Zinnecker H. 
Published: July 2016

The goal of this round-table discussion is to bring up issues which may be of mutual interest to those working on specific flare and variable stars and those performing wide-field searches for, among other things, counterparts to gamma-ray bursts (GRBs). Admittedly, however, trying to unify the interests of the flare people and the GRB people will be an interesting task. Many of the presentations this week have been devoted to future instrumentation and future modes of observations, but there have been also interesting discussions of specific questions regarding flare stars, variable stars and GRBs. Certainly, wide-field observations of the night sky will continue for the foreseeable future: there are a lot of instruments running now, and there are many instruments being planned. Most of these observations cover many square degrees of sky for long periods with a reasonable magnitude limit. How could these observations could be modified or improved to also allow useful data on on variable stars or flare stars to be taken? What sort of information, statistics, periodicities could be gleaned from wide-field searches that will be happening in the future and searches that are going on today? Are there methods in common use by one group of observers that may be useful to the other?The speakers in this session have volunteered to give a short presentation on issues which may benefit from discussion within this group.
The FIP Effect and Abundance Anomalies in Late-Type Stellar Coronae
Authors: Drake J.J. , Laming J.M. , Widing K.G. 
Published: July 2016

“Yes, it will be a long time before people know what I know. How much of iron and other metal there is in the sun and the stars is easy to find out, but anything which exposes our swinishness is difficult, terribly difficult” (Tolstoy 1889).In the solar corona, the abundances of elements appear to differ from the photospheric values in a manner related to the element first ionization potential (FIP): species with FIP ≤ 10 eV are observed to be enhanced relative to the photosphere by factors of ~3−4. The first studies of stellar coronal composition with EUVE suggest that some stars exhibit a solar-like FIP effect, whereas others do not. We briefly review the latest results, and we argue that element abundance anomalies, such as the FIP effect, can provide potentially powerful new coronal diagnostics. Moreover, knowledge of the composition of a stellar corona is crucial for interpreting its spectrum—for understanding its structure and energy balance, and for testing its possible heating mechanisms: We must begin to understand coronal abundance anomalies and the compositions of active stars in order to begin to understand their coronal physics.
Population II Stellar Structure and Evolution: A Few Selected Topics
Authors: Chiosi Cesare 
Published: July 2016

AbstractIn this review we discuss in some detail the evolution of low mass stars, and other related topics, limiting ourselves to the class of stars with solar and super-solar metal content that likely constitute the basic component of elliptical galaxies and bulges. In particular, we deal with the stars responsible of the UV flux observed in elliptical galaxies and the role played by the chemical composition and mass loss by stellar wind in producing hot progenies with effective temperatures in the range indicated by the UV data. In this context, we briefly report on recent chemo - spectro - photometric models for elliptical galaxies. In addition to this, we discuss the subject of galaxy ages by means of the ultraviolet properties and narrow band indices. Finally, we briefly report on a new formulation of diffusive mixing in stellar interiors and its effects on the structure and evolution of intermediate- and high-mass stars.
Precision Asteroseismology of DAV (ZZ Ceti) White Dwarf Stars
Authors: Bradley Paul A. 
Published: July 2016

AbstractRecently, Clemens suggested that the similarity in period structure of the hotter DAV (ZZ Ceti) stars could be explained if they pulsated in a common set of modes. Here, I use theoretical pulsation periods from a new grid of evolutionary DA white dwarf models to determine the internal structure of G 117–B15A and R 548. Both stars have hydrogen layer masses of × 1.5 × 10−4M* and oxygen-rich cores with a composition gradient starting near 0.75M*.
Analysis of the Asteroseismological Data of Six δ Scuti Stars in the Open Cluster NGC 6134
Authors: Audard Nathalie , Kjeldsen Hans , Frandsen Søren 
Published: July 2016

AbstractSix δ Scuti stars have been detected in the open cluster NGC 6134 (Frandsen et al. 1995). A first mode identification attempt shows that several radial modes of radial order n = 0, 1, 2 or 3 might have been observed. We may also be dealing with g-modes and/or modes split by rotation.
Baade-Wesselink Analysis of a Sample of Equal Period SMC Cepheids A progress report
Authors: Storm Jesper , Carney Bruce W. , Freedman Wendy , Madore Barry F. 
Published: July 2016

AbstractWe present a progress report on a project to investigate the differences in absolute physical parameters for a sample of five equal period SMC Cepheids from a Baade-Wesselink analysis of the stars.
The Distribution of the RR Lyrae Variables in ω Centauri and Background Light
Authors: Petersen J. O. , Andersen M. 
Published: July 2016

AbstractThe distribution of the RR Lyrae stars in the globular cluster ω Centauri is studied, using the data published by Martin in 1938. Comparing the accumulated numbers of variables within the angular distance, r, from the centre of the cluster, it is shown that the known RRc variables seem to be less concentrated towards the centre than the RRab stars. 6-10 RRc stars are missing within r = 2–3 arcmin, if the two distributions are actually identical, as expected from evolution models. We conclude that the central region may contain several RRc stars that have not yet been discovered. This could be due to their relatively low amplitude, since it is very difficult to find low-amplitude variables by means of photographic photometry in the crowded, central region of ω Cen with large and varying corrections due to unresolved background light.
The Temperature of the Supergiant α Per
Authors: Evans Nancy Remage , Teays Terry J. , Taylor Lyla L. , Lester John B. , Hindsley Robert B. 
Published: July 2016

AbstractWe compare observed fluxes from the ultraviolet (IUE) through J and K with recent Kurucz model atmospheres to determine a temperature for the F5 lb supergiant α Per. The two most important advances in this study as compared with previous work are the use of well calibrated ultraviolet fluxes and the use of models with an appropriate microturbulence.
A New, Systematic Search at 1612 MHz for OH/IR Stars in the Inner Galaxy
Authors: Sevenster M.N. , Habing H.J. , Chapman J.M. , Killeen N.E.B. 
Published: July 2016

We have surveyed the inner part of the Galaxy for OH 1612 MHz maser emission from OH/IR stars. The full survey is expected to give around 2000 detections. Here we report initial results for the Bulge region between |l| < 10° and |b| < 3°.The observations discussed here were taken with the Australia Telescope Compact Array in Oct-Nov 1993. For each field we used a total integration time of 8 min. spread over an hour-angle range of 12 hours in intervals of an hour. Interference in the 1612 MHz band is a major concern in this program - it is ubiquitous for the shorter baselines. Another concern is the beam-pattern resulting from taking short cuts spread over 12 hours, with a one dimensional array. This causes sidelobe patterns which can easily lead to spurious detections. In addition to these problems, the size of the data set calls for special reduction techniques. We have developed a non-interactive method that is not I/O intensive and is well suited for use on supercomputers. To identify the OH/IR stars, all fields are ‘skimmed’ at successively weaker levels, subtracting point sources at the positions of the highest peaks in the fields, until we reach the (known) 3 σ level. Our method reduces the data reduction time by a factor of eight whilst giving comparable results to conventional cleaning methods. The disk space required is reduced by a factor of 100.
On the Formation of Hydrogen Emission Lines in Miras
Authors: de Laverny Patrick , Magnan Christian 
Published: July 2016

AbstractWe investigate non-LTE effects in the hydrogen recombination zone of Long-Period Variables of Mira type. We propose that the Balmer hydrogen emission lines could be formed in this deep layer. We show how the spectral cyclic variations of Miras could be mimicked with this interpretation. As a result the radius of a Mira in the Balmer transitions could be much smaller than its radius in the molecular absorptions, which are formed in higher layers.
A Nonlinear Pulsation Model for V652 Her
Authors: Fadeyev Yu. A. , Lynas-Gray A. E. 
Published: July 2016

AbstractWhen compared with observation, stellar pulsation model predictions provide a test of stellar envelope opacities. Of specific interest, is the radially pulsating extreme helium star V652 Her for which luminosity and radial velocity observations are published. Nonlinear pulsation models of V652 Her, calculated using Opacity Project (OP) opacities, predict luminosity and radial velocity variations in close agreement with observation.
The Pulsating White Dwarf L19-2
Authors: Sullivan Denis J. 
Published: July 2016

AbstractPrevious studies of the southern DAV white dwarf L19-2 have revealed that it pulsates non-radially in at least five modes with periods ~ 102 s and amplitudes less than 10 mmag. All of these modes showed fine structure splitting, but the one-day aliases resulting from the gaps in the single-site data made identification of the various frequencies, at best, difficult. Recent observations of L19-2 obtained from Mt. John (NZ) are presented, along with a discussion of the prospects for a Whole Earth Telescope run on this object scheduled for 1995.
Visibility Functions of Solar and Stellar Irradiance Variations
Authors: Staude Jürgen , Bartling Günter , Zhugzhda Yuzef D. , Dzhalilov Namig S. 
Published: July 2016

AbstractWe calculated visibility functions of intensity fluctuations due to adiabatic waves in a realistic model of a non-grey, stratified atmosphere in LTE. The results for different optical wavelengths λ and their angular dependence are discussed; moreover, a method for selecting various low-degree p-modes from observations of spectral irradiance fluctuations at different λ including the UV is suggested.
The Nova-Likes AC Cnc, RW Tri, UX UMa and the Nova DQ Her: Common and Different Properties
Authors: Dmitrienko E. S. 
Published: July 2016

AbstractAn analysis of the main photometric properties of the nova-like variables AC Cnc, RW Tri and UX UMa, and Nova Her 1934 (DQ Her) is presented. The analysis is based on simultaneous high-speed UBVRI photometry, covering several dozens of orbital cycles evenly distributed over 14 years (1982 ... 1995) for DQ Her, and over 11 years (1985 ... 1995) for the other three stars. All data have been obtained with the 1.25 m telescope at the Crimean Astrophysical Observatory.
Roche Tomography of the Cool Star in IP Peg
Authors: Rutten R. G. M. , Dhillon V. S. 
Published: July 2016

AbstractWe analyse orbitally-resolved spectra of the Na I doublet in the dwarf nova IP Peg, using the newly developed technique of Roche tomography. We show that Roche tomography can be successfully employed to image the secondary stars in CVs, and that it also serves as an independent aid for determining binary system parameters. Our preliminary results suggest that the mass of the white-dwarf primary is 1.2 M⊙, significantly higher than previous estimates.
TT ARI–94: A Study of 1.6…60 Minute Variability
Authors: Andronov I. L. , Arai K. , Chinarova L. L. , Dorokhov N. I. , Dorokhov T. A. , Dumitrescu A. , Nogami D. , Lepardo A. , Mason P. A. , Matumoto K. , Oprescu G. , Pajdosz G. , Passuelo R. , Patkos L. , Sostero G. , Tremko J. , Zola S. 
Published: July 2016

We report photometric results from 44 runs at 11 observatories during the international campaign ‘TT Ari–94’. No coherent oscillations in the frequency range 10… 900 cycle d−1 are found. The highest peaks in the power spectrum cover the wide range of 28… 139 cycle d−1. Variations occur at a few preferred time-scales rather than at one cycle length, with a possible secular decrease. In the frequency range 90… 900 cycle d−1 the power spectrum obeys a power law with slope γ ranging from 0.8 to 2.6 for different runs.TT Ari is one of the brightest cataclysmic variables and remains one of the most interesting objects of this class. It exhibits a variety of phenomena observed at time-scales from seconds to months. A recent detailed photometric study of this object and a bibliographical overview may be found in Tremko et al. (1996). Tremko et al. (1992, 1993, 1994) discuss aspects of the TT Ari–88 campaign. Our campaign TT Ari–94 was unprecedented, as the observations were longitude-dispersed, from Japan through Turkmenia, to Europe and the American continent. Moreover, our optical data on October 7 partially overlap with the HST observations obtained by Home & Welsh (1995, private communication). The numerical results of observations obtained during these nights are shown in Table 1.
Outburst Activity Data on Selected Cataclysmic Variables
Authors: Vanmunster T. , Howell S. B 
Published: July 2016

AbstractWe have created a database with outburst activity for 269 selected cataclysmic variables. It includes nearly 1000 outburst measurements discovered through 1995 June. The database and a complete paper describing the observations and the sources of information that were consulted are accessible over the Internet.
Observation of the WZ Sge-Type Dwarf Nova AL Com
Authors: Kato T. , Nogami D. , Baba H. , Matsumoto K. , Arimoto J. , Tanabe K. , Ishikawa K. 
Published: July 2016

AbstractAlthough presently classified as a SU UMa-type dwarf nova, WZ Sge is well known as one of the most peculiar objects in that it shows only superoutbursts with exceptional duration and amplitude, and no normal outbursts. Furthermore, on its decline from the 1978 outburst, WZ Sge showed a deep temporal dip. All of these characteristics have puzzled both theoreticians and observers.The dwarf nova AL Com was photometrically observed during the outburst in 1995 April, which occurred for the first time since 1975. The striking similarity of AL Com to WZ Sge, as demonstrated by the present observation (Fig. 1), provides plenty of material in interpreting the enigmatic nature of WZ Sge-type dwarf novae.