bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quasi-Lntegrals of the Plane Restricted Three-Body Problem
Authors: Nezhinskij E.M. 
Published: July 2016

AbstractThe paper is concerned with studying the domain of possible motion and a field of the test body velocities in the plane restricted problem of three bodies. The study is based on existence of a quasi-integral of areas (similar to an integral of areas in the problem of two bodies) as well as on the Jacobi integral. The method of constructing the quasi-integrals is a standard one (see, for example, [1],[2].
Application of Szebehely’s Inverse Problem to Non-Stationary Dynamical Systems
Authors: Omarova G.T. , Kozhanov T.S. 
Published: July 2016

AbstractA first-order linear partial differential equation is presented, giving the non-stationary potential functions U=U (x,y,t) which give rise to a given family of evoling planar orbits f(x,y,t) = c in two-dimensional dynamical system. It is shown, that this equation is applied in celestial mechanics of variable mass.
Planar Oscillation of the Satellite Near Parametric Resonance in the Elliptic Orbit
Authors: Singh Ram Binoy 
Published: July 2016

AbstractThis paper is devoted to the study of motion of an artificial satellite relative to its centre of mass near parametric resonance in elliptic orbit. It is well known fact that the satellite, of the form of an ellipsoid with three unequal axes, while moving about the central planet, oscillates about the stable position of equilibrium (the longest axis of the satellite coinciding with the radius vector of its centre of mass). The oscillation of the satellite about this position of equilibrium in the orbital plane of its centre of mass is described by a well known second order nonlinear differential equation with a periodic sine force. Naturally there will be resonance cases (main as well as parametric) for such a systems. In the previous author’s work, it was discovered a series of parametric resonances for the system, which corresponds to n = ½k where k is a non-zero integer and n is a parameter depending on the shape of the satellite. The parametric resonance, for k = 1, has been considered here. The first approximate solution of the equation of motion has been obtained by Eogoliubov-Krilov method with e (the eccentricity of the orbit of the centre of mass of the satellite) as the small parameter. This method enables us to visualise the oscillation of the satellite for the resonance case as well as near the resonance. Three stationary values of the amplitudes and phase of oscillation have been obtained, out of which only one is stable near this particular parametric resonance. At the resonance there appear only one stationary regime of oscillation with a very small amplitude.
Study of Cosmic Dust Particles on Board LDEF and MIR Space Station
Authors: Mandeville J.C. 
Published: July 2016

AbstractInterplanetary and near-earth space contains solid objects whose size distribution continuously covers the interval from submicron sized particles to km sized asteroids or comets. Two French experiments partly devoted to the detection of cosmic dust have been flown recently in space. One on the NASA Long Duration Exposure Facility (LDEF), and one on the Soviet MIR Space Station. A variety of sensors and collecting devices will make possible the study of cosmic particles after recovery of exposed material. Flux mass distribution is expected to be derived from craters counts, with a good accuracy. Remnants of particles, suitable for chemical identification are expected to be found within stacked foil detectors. Discrimination between extraterrestrial particles and man-made orbital debris will be possible.
The Munich Dust Counter — A Cosmic Dust Experiment on Board of the Muses-A Mission of Japan
Authors: Igenbergs E. , Hüdepohl A. , Uesugi K. , Hayashi T. , Svedhem H. , Iglseder H. , Koller G. , Glasmachers A. , Grün E. , Schwehm G. , Mizutani H. , Yamamoto T. , Fujimura A. , Ishii N. , Araki H. , Yamakoshi K. , Nogami K. 
Published: July 2016

AbstractThe Munich Dust Counter (MDC) is a scientific experiment on board of the MUSES-A mission of Japan. It is the result of a cooperation between the Institute of Space and Astronautical Science (ISAS) of Japan and the Chair of Astronautics of the Technische Universität München (TUM) of Germany. The MDC is an impact ionization detector designed to determine mass and velocity of cosmic dust. Here a short overview over the MUSES-A mission is given to show the measurement situation of the MDC experiment. The measurement principle of the instrument together with a discussion of the scientific objectives and the design of the experiment is summarized.
Physical and Mineralogical Properties of Anhydrous Interplanetary Dust Particles in the Analytical Electron Microscope
Authors: Bradley J. P. 
Published: July 2016

AbstractThe fine grained mineralogy and petrography of anhydrous “pyroxene” and “olivine” classes of chondritic interplanetary dust have been investigated by numerous electron microscopic studies. The “pyroxene” interplanetary dust particles (IDPs) are porous, unequilibrated assemblages of mineral grains, metal, glass, and carbonaceous material. They contain enstatite whiskers, FeNi carbides, and high-Mn olivines and pyroxenes, all of which are likely to be well preserved products of nebular gas reactions. Solar flare tracks are prominent in most “pyroxene” IDPs, indicating that they were not strongly heated during atmospheric entry. The “olivine” IDPs are coarse grained, equilibrated mineral assemblages that have probably experienced strong heating. Since most “olivine” IDPs do not contain tracks, it is possible that this heating occurred during atmospheric entry.
The Zodiacal Cloud Complex
Authors: Levasseur-Regourd A.C. , Renard J.B. , Dumont R. 
Published: July 2016

AbstractThe physical properties of the interplanetary dust grains are, out of the ecliptic plane, mainly derived from observations of zodiacal light in the visual or infrared domains. The bulk optical properties (polarization, albedo) of the grains are demonstrated to depend upon their distance to the Sun (at least in a 0.1 AU to 1.7 AU range in the symmetry plane) and upon the inclination of their orbits (at least up to 22°). Classical models assuming the homogeneity of the zodiacal cloud are no longer acceptable. A hybrid model, with a mixture of two populations, is proposed. It suggests that various sources (periodic comets, asteroids, non periodic comets...) play an important role in the replenishment of the zodiacal cloud complex.
On The Gegenschein and the Symmetry Plane
Authors: Hong S. S. , Kwon S. M. 
Published: July 2016

AbstractUsing 3-dim density models of the zodiacal cloud, we have calculated brightness of the zodiacal light over an extended region around the anti-solar point. The isophotal contours of the model Gegenscheins differ from each other, morphologically, to the degree that they can differentiate the competing density models. The recently reduced Gegenschein observations of 2° resolution clearly favour the ellipsoid-type models to the fan-types, and also suggest that the surface of the densest dust concentration in the outer part of the cloud has its ascending node at longitude 100 ± 20° and is inclined 2 ± 0°.5 with respect to the ecliptic plane.
Synthetic Maps of the Brightness and Polarization of the F-Corona
Authors: Fang Y. , Lamy P.L. , Llebaria A. 
Published: July 2016

AbstractThe Wide-Field Light and Spectrometric Coronograph (LASCO) to be flown on SOHO in 1995 is designed to perform accurate photopolarimetric observations of the solar corona. For simulation purpose but also to have a two-dimensional model of the F-corona, we have realized synthetic maps of its brightness and polarization
Dust in Planetary Ring Systems
Authors: Showalter Mark R. 
Published: July 2016

AbstractEach of the outer gas giants Jupiter, Saturn, Uranus and Neptune is now known to be encircled by a system of rings. Some of these, such as the A, B, and C rings of Saturn and the nine narrow Uranian rings, are rather optically thick and are composed primarily of large bodies (1 cm to 10 m). However, every other system has been found to contain a large population of micron-sized dust. Such rings reveal the effects of a variety of physical processes that are also acting on interplanetary and interstellar grains. When such rings are examined as members of a general class, recurring patterns begin to emerge.
Convection in the Sun
Authors: Massaguer Josep M. 
Published: July 2016

AbstractThe present knowledge of the dynamics and structure of the solar convection zone is reviewed with the aim of checking current assumptions and conjectures against laboratory experiments and numerical modeling of thermal convection. Buoyancy is the only forcing considered. Rotation and magnetic fields are explicitly avoided. Nor are departures from planar geometry considered, except as regards large scale structures. Local theories are reviewed in section §2, hydrodynamic models in §3, non-local theories in §4, the global structure of the convection zone is discussed in §5 and the flow patterns in §6.
Solar and Stellar Cycles
Authors: Belvedere Gaetano 
Published: July 2016

AbstractThe increasing observational evidence offered by photometric and spectroscopic data of magnetic cycles in lower main sequence stars, has confirmed the general expectation that the same basic dynamo mechanism operates in the Sun and main sequence in stars with outer convective envelopes.Unfortunately, no clear correlation has been found, up to date, with stellar parameters as mass, rotation rate and age, even if irregular activity and shorter cycle periods seem to be characteristic of stars more massive than the Sun, while hyperactive fast rotating components of binary systems like RS CVn’s and BY Dra’s show a tendency for cycles as long as several decades.Although dynamo theory has probably captured die essential physics of the convection-rotation interaction giving rise to stellar magnetic activity, as evidenced, for instance, by the correlation between proxy activity, indicators and the Rossby parameter related to the dynamo number, the reliability of the present theoretical background should be measured by its capacity of interpreting and predicting characteristics and periodicities (or aperiodicities) of stellar cycles. This should be done in the framework of the nonlinear approach, which, in principle can describe multimodal dynamo behaviour with a variety of time scales.The fundamentals of the theory must be tested, however, in the closest astrophysical laboratory, our Sun. Serious problems to a dynamo mechanism operating in the convection zone have been posed by most recent helioseismological results, which, on the other hand, do not rule out the possibility of dynamo action in the transition layer between the convective and die radiative zones, which is suggested independently by the global solar cycle features. Indeed, assuming the correct sign of helicity in the transition layer, the helioseismological data on the radial gradient of angular velocity support both equatorward propagation of dynamo waves at lower latitudes and poleward propagation at higher latitudes, which is evidenced by different tracers of the solar cycle.
The Solar Dynamo
Authors: Rädler K.-H. 
Published: July 2016

AbstractThe phenomena of solar activity are connected with a general magnetic field of-the Sun which is due to a dynamo process essentially determined by the α-effect and the differential rotation in the convection zone. A few observational facts are summarized which are important for modelling this process. The basic ideas of the solar dynamo theory, with emphasis on the mean-field approach, are explained, and a critical review of the dynamo models investigated so far is given. Although several models reflect a number of essential features of the solar magnetic cycle there are many open questions. Part of them result from lack of knowledge of the structure of the convective motions and the differential rotation. Other questions concern, for example, details of the connection of the α-effect and related effects with the convective motions, or the way in which the behaviour of the dynamo is influenced by the back-reaction of the magnetic field on the motions.
The Galactic Nova Rate
Authors: Della Valle M. , Claudi R. 
Published: July 2016

AbstractThe recently estabilished values of M31 and M33 nova rate, rM31 = 29 ± 4 novae yr−1 (Capaccioli et al.,1989), rM33 = 4 ± 2 novae yr−1 (Della Valle, 1988), seems to be at variance with the present estimates for the galactic nova rate, r = 260 novae yr−1 (Sharov,1972) and r = 73 ± 24 novae yr−1 (Liller and Meyer,1987), if we take into account the luminosity class and the Hubble type of the Galaxy. Assuming the nova production per unit of B–luminosity about constant for spiral galaxies and adopting the derived values of the nova rate of M31, M33 and LMC as calibrators, we estimate a galactic nova rate of rGal = 15 ± 5 novae yr−1.
Optical Imagery of Nova Remnants
Authors: Wade Richard A. 
Published: July 2016

AbstractResolved nebular remnants of classical novae are discussed in terms of size, surface brightness, and shape. A list of 26 known resolved remnants is given. The conditions necessary for visibility of a resolved remnant are discussed. The structure of remnants can be studied at optical wavelengths by direct imaging and by long-slit or otherwise spatially resolved spectroscopy of emission lines. Based on recent spatiokinematic studies, most nebular remnants are prolate in outline, with sub-structure that has been characterized as consisting of “polar blobs” and “equatorial rings”. The mechanism that shapes the remnants is not yet known with certainty. There is room for much additional work in discovering new remnants and in characterizing those that are known.
HM Sge still evolving
Authors: Nussbaumer H. , Vogel M. 
Published: July 2016

In their study on C/N/O abundances in red giants, planetary nebulae, novae and symbiotic stars Nussbaumer, Schild, Schmid and Vogel (1988: Astron.Astrophys.198, 179) pointed out that among symbiotic stars HM Sge is quite exceptional, in that its C/N/O abundance ratios rather resemble those of novae and not of symbiotic stars.In 1975 HM Sge brightened within a few months by at least 4m. The object has been observed in radio, visual, X-ray, and since 1978 with IUE. Here we show the changing level of activity in the UV. Figure 1 gives the FES (IUE fine error sensor) counts, representing an integrated flux at visual wavelengths. This flux shows a general decline with a secondary maximum in 1982. – Our mFES is at variance with the visual magnitude estimates given by Munari and Whitelock (1989: Mon.Not.Roy.astr.Soc. 237, 45p). They report high brightness up to at least the end of 1984.
2. Catalytic Reactions in the Solar Nebula
Authors: Anders E. , Hayatsu R. , Studier M. H. 
Published: July 2016

Organic compounds in meteorites seem to have formed by Fischer-Tropsch-type, catalytic reactions of CO, H2, and NH3 in the solar nebula, at 360-400 K (and 4-10) x 10-6 atm. The onset of these reactions was triggered by the formation of catalytically active grains of magnetite and serpentine at these temperatures.Laboratory experiments show that the Fischer-Tropsch reaction gives a large kinetic isotope fractionation of C12/C13, duplicating the hitherto unexplained fractionation in meteorites. All of the principal compound classes in meteorites are produced by this reaction, or a variant involving a brief excursion to higher temperatures. (1) normal, mono-, and dimethylalkanes; (2) arenes and alkylarenes; (3) dimeric isoprenoids from Cg to C14; (4) purines and pyrimidines, such as adenine, guanine, uracil, thymine, xanthine, etc.; (5) amino acids, including tyrosine and histidine; (6) porphyrin-liJce pigments; (7) aromatic polymer with -OH and -COOH groups.These reactions may also have played a major role in the evolution of life: first, by converting carbon to a sufficiently non-volatile form to permit its accretion by the inner planets; second, by synthesizing organic compounds on the primitive planets whenever CO, H2, NH3, and clay or magnetite particles came together at the right temperature. Similar reactions in other solar nebulae may be the source of interstellar molecules, as first suggested by G. H. Herbig. Ten of the twelve polyatomic interstellar molecules have in fact been see in these synthesis or in meteorites.
Observations of the Local Interstellar Cloud
Authors: Lallement R. 
Published: July 2016

AbstractConstraints on the ambient (circumsolar) interstellar medium can be derived from observations of interstellar neutrals or their derivatives in the heliosphere. New results have been recently obtained which, when combined with optical and UV observations of the nearby stars (HST-GHRS, EUVE), remove long-standing contradictions and allow us to infer for our local cloud, pressure, ionization and limits on the magnetic field. The electron density in the circumsolar gas is found to be between 0.04 and 0.15 cm−3. Its total thermal pressure is within the interval 1700 – 2600 cm−3 K. If the local magnetic field is nearly perpendicular to the interstellar wind flow, which is likely, then its intensity is smaller than 3.6 μG. Our Sun is located very close to the edge of the local cloud (the volume of gas which has the same physical properties as the circumsolar gas), while there are at least 5 other cloudlets within 10 pc. Abundances vary from cloudlet to cloudlet. How they are located and whether they are separated by tenuous gas or shock discontinuities is not clear yet. Semi-hot (105 K) gas has been detected in absorption towards nearby stars (Wood et al, 1996), which probably originates in the “H walls” surrounding our heliosphere and other asterospheres. This shows that semi-hot gas is not necessarily linked with cloud interfaces with the hot gas of the Local Bubble.
The Intrinsic Properties of the Local Interstellar Medium
Authors: Puyoo Olivia , Ben Jaffel Lotfi 
Published: July 2016

AbstractWe propose a new method to constrain the actual state of the interstellar cloud that surrounds the solar system. Using Voyager UVS Lyman-α sky maps and the powerful principle of invariance, we derive the H distribution all along the spacecraft path. Provided current models of the heliopause interface between the solar and the interstellar winds, we extrapolate this distribution to farther distances from the Sun and infer in a self consistent way key parameters of the local cloud. Our findings are a high interstellar hydrogen density of ~ 0.24 cm−3 and a weak ionization .
EURD: An Extreme Ultraviolet Spectrograph to Probe the Hot Interstellar Medium
Authors: Morales C. , Trapero J. , Gómez J.F. , Bowyer S. , Edelstein J. , Lampton M. 
Published: July 2016

AbstractThe EURD instrument has been designed to measure diffuse emission in the extreme ultraviolet (350–1100 Å). This new design provides an unprecedented 4–5 Å spectral resolution and 200 photons/sec/cm2/sr sensitivity after only 100 hours of observations. One of the goals of this project is to search for spectral lines of highly ionized species from the high temperature component (105 – 106 K) of the interstellar medium that fills the Local Bubble. It is expected that EURD will detect lines due to a thermalized hot component of the interstellar medium, and it will also provide critical diagnostics of the physical properties of this gas. With EURD data we could also detect a spectral line due to the decay of massive neutrinos as well as study oxygen lines from the upper atmosphere airglow. EURD is on board the Spanish MINISAT-01 satellite.
The Thermal Pressure of the Interstellar Medium Derived from Cloud Shadows in the Extreme Ultraviolet
Authors: Berghöfer Thomas W. , Bowyer Stuart , Lieu Richard , Knude Jens 
Published: July 2016

AbstractWe have used the Deep Survey telescope of EUVE to investigate shadows in the diffuse EUV/Soft X-ray background cast by clouds in the interstellar medium. We confirm the existence of a shadow previously reported, and provide evidence for two new shadows. We used IRAS data to identify the clouds producing these shadows and to determine their optical depth to EUV radiation. The EUV-absorbing clouds are optically thick in the EUV, and all EUV emission detected in the direction of these shadows must be produced from material in front of the clouds. We obtained new optical data to determine the distance to these clouds. We use a new differential cloud technique to obtain the pressure of the interstellar medium. These results do not depend on any zero level calibration of the data. Our results provide evidence that the pressure of the hot interstellar gas is the same in three different directions in the local interstellar medium, and is at least 8 times higher than derived for the local cloud surrounding our Sun. This provides new evidence for large thermal pressure imbalances in the local ISM, and directly contradicts the basic assumption of thermal pressure equilibrium used in almost all present models of the interstellar medium.
Thin Layer Approximation in 3-D
Authors: Bisnovatyi-Kogan G.S. , Silich S.A. 
Published: July 2016

AbstractEquations are derived which describe the propagation of strong shocks in the interstellar matter, without any restrictions for symmetry, in a thin layer approximation (2.5 dimensions). Using these equations permits to calculate the propagation of shock waves from nonsymmetric supernovae explosions in a medium with arbitrary density distribution and the formation of superbubbles in galaxies.
Magnetorotational Mechanism: 2D Simulation
Authors: Ardeljan N.V. , Bisnovatyi-Kogan G.S. , Moiseenko S.G. 
Published: July 2016

AbstractIn the paper we present results of numerical simulations of magnetorotational model of explosion of magnetized cloud. For the simulation we used a specially developed 2D implicit numerical scheme on Lagrangian triangular grid with grid reconstruction. Our results show that due to the amplification of toroidal magnetic field component and transfer of angular momentum, a compression wave in the envelope of the cloud appears and moves through rapidly decreasing density background. This wave turns into a shock wave and pushes out part of the envelope of the star. Quantitative estimates of mass and energy carried away are given.
Imaging Polarimetry of Nearby Molecular Clouds
Authors: Ramaprakash A.N. , Tandon S.N. , Gupta R. 
Published: July 2016

AbstractIn order to study the role played by the magnetic fields in the dynamics of the interstellar medium (ISM) a two-channel imaging polarimeter (IMPOL) has been constructed. The instrument is capable of multi-wavelength observations in the visible and very near infrared (IR) wavelengths, has a sensitive CCD detector and a built-in acquisition and guidance unit. When used with a 1.2m, f/13 telescope IMPOL gives a field of view of 6 × 6 arcmin with an angular resolution of 2" so that it is well-suited to observe both faint extended objects and moderately crowded stellar fields. The instrumental polarization is less than 0.05% and the accuracy of the measurements is primarily limited by photon noise in a typical observation. In this paper, we present a brief description of the instrument and observational techniques, as well as the results of a successful observation of a molecular cloud close to the open cluster IC 5146.