bluuebunny/crossref_metadata_2025 huggingface dataset:
A Second-Order Theory of the Galilean Satellites of Jupiter
Authors: Ferraz-Mello S.
Published: July 2016

The theory of the motion of the Galilean satellites of Jupiter is developed up to the second-order terms. The disturbing forces are those due to mutual attractions, to the non-symmetrical internal mass distribution of Jupiter and to the attraction from the Sun. The mean equator of Jupiter is taken as the reference plane and its motion is considered. The integration of the equations is performed. The geometric equations are solved for the case in which the amplitude of libration is zero. The perturbation method is shortly commented on the grounds of some recent advances in non-linear mechanics.

In a previous paper (Ferraz-Mello, 1974) one perturbation theory has been constructed with special regard to the problem of the motion of the Galilean satellites of Jupiter. In this problem, the motions are nearly circular and coplanar; on the other hand the quasi-resonances lead to strong perturbations. The main characteristic of the theory is that it allows the main frequencies to be kept fixed from the earlier stages, and so, to have a purely trigonometric solution.
Some Considerations on the Theoretical Determination of the Potential by the Motion of Artificial Satellites in the Plane Case
Authors: Martinez-Benjamin J.J.
Published: July 2016

We consider the determination of the potential from the orbit of a satellite. The potential obtained is not unique because the satellite might describe the same orbit with different forces. The classical problem of determination of orbits has a unique solution, for given initial conditions. The problem is reduced to the planar case with a conservative force. The mathematical results depend on the arbitrary functions of the system of coordinates used.
Displacement of the Lagrange Equilibrium Points in the Restricted Three Body Problem With Rigid Body Satellite
Authors: Robinson W.J.
Published: July 2016

In the restricted problem of three point masses, the positions of the equilibrium points are well known and are tabulated. When the satellite is a rigid body, these values no longer correspond to the equilibrium points. This paper seeks to determine the magnitudes of the discrepancies.
Resonance in the Restricted Problem of Three Bodies With Short-Period Perturbations in the Elliptic Case
Authors: Bhatnagar K. B. , Gupta Beena
Published: July 2016

This is a generalization of the paper by Bhatnagar and Beena Gupta ‘Resonance in the restricted problem of three bodies with short-periodic perturbations’. The motion of an asteroid moving in the gravitational field of Jupiter is considered. In the original paper it was assumed that Jupiter is moving in a circular orbit around the Sun. In the present paper we consider the orbit to be elliptic. The series occurring in the problem are expanded in powers of a small parameter ε, which represents the ratio of the mass of Jupiter to that of the Sun. The perturbations in the osculating elements are obtained up to 0(ε).
Spectral Classification of Peculiar Red Giants
Authors: Keenan Philip C.
Published: July 2016

Among field stars recent work includes development of classification notation of the strong-CN stars, and the recognition that the barium star with weak CN (HD 130255) may actually be a dwarf barium star. The now established presence of weak-G-band stars on the AGB of globular clusters suggests that such field stars as HD49500 may be in the AGB stage.

Such progress as has been made in the application of modern detectors to the classification of faint stars in the nuclear bulge of our galaxy, and in the Magellanic Clouds, is summarized.
Multi-Wavelength Observations of the Peculiar Red Giant HR 3126
Authors: Pesce Joseph E. , Stencel Robert E. , Doggett Jesse , Walter Frederick M. , Whitelock Patricia A. , Dachs Joachim
Published: July 2016

The M2 II star HR 3126 (HD 65750) is remarkable because it sits near the center of a 0.7M⊙ butterfly-shaped reflection nebula of several arc minutes extent (Dachs et al. 1978, A & A 63, 353.). If it is a member of the nearby open cluster NGC 2516, the distance (375 pc), main sequence turnoff age (~ 108 years) and implied mass (~ 5Mʘ) suggest that IIR 3126 is a red bright giant past the initiation of helium burning in its core.
Molecular Bands in the 1.1-1.4 μm Spectra of M-S-C stars
Authors: Hinkle Kenneth H. , Lambert David L. , Wing Robert F.
Published: July 2016

Spectra are presented in the J band (7400 to 9700 cm-1) for four Miras ranging in spectral type from M through C. All the program stars have been observed near minimum light. The program stars cover a considerable range in C/0 and the spectral features exhibit a progression as a function of C/0. The S-type stars contain strong bands not previously reported. Especially striking are two sets of triple-headed bands in the J-band spectrum of the S-type Mira R And. The bandheads, which are degraded to longer wavelengths, are at 7877, 7957, 8030 cm-1 and 8379, 8459, 8530 cm-1. The former triplet, which is the stronger of the two, also is present in the mild S star × Cyg but not in the M star R Cas. Additional heads are found in R And at 7477 cm-1, near the short wavelength edge of strong telluric absorption, and at 8968, 9031, 9063 cm-1. The bands are identified as the Δv = -1, 0, 1, and 2 sequences of a predicted (3II-3Δ) transition of ZrS. Additional conspicuous features in the spectra of × Cyg and R Cas are identified with V0, TiO, and H20 bands. These observations provide additional evidence that ZrS is responsible for the majority of the Keenan-Wing bands in the near infrared (0.7-1.1 μ). With additional laboratory work, the ZrS bands will provide an opportunity to measure sulfur abundances in late-type stellar photospheres.
Hydrogen Deficiency in Peculiar Red Giants
Authors: Wing Robert F. , Saizar Pedro
Published: July 2016

Hydrogen abundances (or H/He ratios) are hard to determine in stars cooler than the Sun because the Balmer lines, when visible at all, are formed largely in the chromosphere, while the bands of CH and NH are often strongly saturated and badly blended with atomic lines. A few stars (the hydrogen-deficient carbon or HdC stars) are known to be extremely hydrogen-deficient, as their G bands of CH are absent despite an overabundance of carbon. A means of detecting less extreme cases of hydrogen deficiency would improve our understanding of red giant evolution. Minor variations in hydrogen content may be expected as the result of the mixing of processed material to the surface, and more radical changes might result from a star's shedding its entire hydrogen-rich envelope, say in the course of binary-star evolution.
Evolution and Mixing on the Agb
Authors: Lattanzio John C.
Published: July 2016

It is now well known that Nature can make Carbon stars at lower luminosities than can (human) theorists. A number of workers, stimulated by this challenge, have been attracted to the problem. In this paper I review recent evolutionary models of relatively low mass AGB stars, with emphasis placed on the mixing of carbon to the stellar surface. In particular I discuss some recent improvements in the physics used to construct stellar models. These topics include: breathing pulses of the convective core found during core helium exhaustion; the effects of carbon recombination; the occurrence of semiconvection in the region between the two nuclear burning shells; and the importance of mass loss. Recent calculations have successfully produced models of low luminosity Carbon stars. The strengths and weaknesses of these models will be contrasted.
A Statistical Study of Spectroscopic Binaries Containing A Late-Type Giant Star
Authors: Boffin H.M.J.
Published: July 2016

Binarity seems to be a feature shared by various classes of Peculiar Red Giants (PRG). This observational fact has led to the general agreement that those stars result from a mass transfer originating from an asymptotic giant branch companion star.
The Effects of Main-Sequence Mass Loss on Surface C/N Abundance Ratios During the Ascent of the First Giant Branch
Authors: Guzik J. A. , Beach T. E.
Published: July 2016

The surface C/N abundance ratios of many cluster and field G and K giants following the 1st dredge-up phase are much lower than predicted from standard stellar evolution modeling. The occurrence of substantial mass loss, either during or immediately after the main-sequence phase would both reduce the mass fraction of the unprocessed envelope necessary to contaminate with CN-cycle products, as well as allow CN-processing of a greater amount of core material during the earlier high-mass phase. Willson, Bowen and Struck-Marcell (1987) have proposed that a combination of pulsation and rapid rotation could drive substantial mass loss in main-sequence stars of initial mass 1-3 MΘ. We evolved a grid of 16 mass-losing models from the zero-age main sequence through 1st dredge-up. The models have initial masses of 1.25, 1.5, 1.75 and 2.0 MΘ, and exponentially decreasing mass-loss rates with e-folding times 0.2, 0.4, 1.0 and 2.0 Gyr; all models evolve toward a final mass of 1.0 M". Since the mass-loss epoch is short-lived, most of the models reach 1.0 M0 rapidly, and follow the evolutionary track of a standard 1 MΘ model redward away from the main sequence and up the 1st giant branch. The convecuve envelope deepens during 1st dredge-up to homogenize the outer 3/4 of the star's final mass.
The Production of Low Mass Carbon Stars; Carbon-rich Dredge Up or Oxygen-rich Mass Loss?
Authors: Stencel R.E. , Pesce J.E. , MacGregor K.M.
Published: July 2016

Conventional theory explains the origin of carbon stars as due to dredge up of carbon enriched material from the stellar core during helium flash events late in the life of solar mass AGB stars (e.g. Boothroyd and Sackmann 1988). This relatively efficient process however, seems to produce a larger C/O ratio than observed (Lambert et al. 1987). A secondary effect which could contribute to the appearance of carbon stars, is the selective removal of oxygen from the atmosphere by radiative force expulsion of oxygen rich dust grains (e.g. silicates like [Mg, Fe2SiO4]). We present calculations for this scenario which evaluate the degree of momentum coupling between the grains and gas under the thermodynamical conditions of AGB star atmospheres.
Early Shaping of Asymmetric Planetary Nebulae
Authors: Soker Noam
Published: July 2016

We suggest that the shape of a young asymmetric planetary nebulae may be influenced by a close binary star located at its center. This binary is a relic of the common envelope phase, presumably through which the asymmetric planetary nebula evolved. We assume that for a short period of time, shortly after the cession of the slow wind and long before the fast wind becomes effective, the binary ejects a small amount of mass, mainly in the equatorial plane. In this work we do not discuss the exact mechanism for the ejection of this pulse of mass. In the case in which the cooling is very efficient, (i.e., high-Mach-number isothermal flow), we can solve the problem analytically by using a few simplifying assumptions. In this case the high density region is shaped like a ring. We use two-dimensional hydrodynamics for the more general case. We find that at late times the high density region has a “horseshoe” shape, as viewed in the symmetry plane. There is an instability in the maximum density region. Finally we compare our results with the shape of the planetary nebula M2-9.
Pulsational Periodicities in R CrB
Authors: Fernie J.D.
Published: July 2016

R CrB has been placed on the program of the Automatic Photometric Telescope Service (Genet et al. Pub. A.S.P. 99, 660, 1987) for continual monitoring while near maximum light UBV data are obtained on almost every clear night during the star's season and will be published in batches every few years
Shock-Induced Behavior of Atomic Species in LPV Atmospheres
Authors: Pierce J. N.
Published: July 2016

A dynamic model of the LPV atmosphere which calculates the time-dependent variations of density, temperature, velocity, and composition with radius has been used to predict changes in absorption line profiles with phase. General results based on density variations are shown in figure 1. Similar graphs, based on concentrations of individual species, are presented for six metals: Fe, Si, Mg, Ca, Cr, and Ti. Those species which remain essentially proportional to the density (e.g., most neutral metals) exhibit the same type of variation. Ionized metals show more individual variations, including some doubling at certain phases, caused by enhanced ionization in the regions traversed by the upper shock. The basic variation predicted by this model has been observed for CO lines in Chi Cygni. (Hinkle, Hall, and Ridgway 1982, Ap. J. 252, 697)
Investigation of a Sample of Long-Period Variable Stars Possessing Maser Emission
Authors: Andronov I.L. , Kudashkina L.S. , Rudnitskij G.M.
Published: July 2016

An investigation of parameters of a sample of more than two hundred late-type long-period variable stars (LPVs) has been carried out. In more detail were studied 13 giants (Mira Ceti-type variables R Aql, RR Aql, RT Aql, R Leo, U Ori, U Her, R Cas, R Tau, Z Cyg, R Peg, U Aur and semiregular variables RT Vir and RX Boo) and 2 supergiants (S Per, PZ Cas). A considerable fraction of the sample stars (about one third) possess circumstellar maser emission in molecular spectral lines (OH, H20, SiO). Our aim was to elucidate the particularities of photometric characteristics of maser stars, such as period P, amplitude A, light curve asymmetry f = (M-m)/P, and, in prospect, to determine their status in course of their evolution on the asymptotic giant branch. An extensive comparison with non-maser LPVs was made.
Line Brightness Variations in Alpha Orionis - Phase Differences and Radial Velocities
Authors: Joras P.
Published: July 2016

Observations of the red, bright supergiant star a Orionis (Betelgeuse) during the past decade show significant variations in UV line fluxes and line shifts. Dupree et al. (1987) pointed out that the data from 1984-1987 indicates a periodicity of slightly more than one year in the B magnitude, UV continuum, and Mg II emission line fluxes. Our data shows that this conclusion applies to other strong and medium strong chromospheric lines as well. The variations seem to affect also the relative strength of lines within multiplets.
Chromospheres of Chemically Peculiar Giant Stars
Authors: Judge P.G.
Published: July 2016

A review is given of the chromospheres of evolved stars with peculiar chemical abundances, emphasizing the observed dependence of chromospheric properties upon the evolutionary status of the stars. Some old and new physical processes which are potentially important in determining the observed chromospheric features are discussed.
The Variability of Water Maser Emission Associated with Long Period Variable Stars
Authors: Little-Marenin I.R. , Benson P.J. , Goodwin D.
Published: July 2016

Since March 1988 we have monitored the 22.2 GHz H20 maser line of 12 long period variable stars (LPV) with the 37 m telescope at the Haystack Observatory. We include the two Carbon stars V778 Cyg and EU And. The maser flux from V778 Cyg has varied by at least a factor of 5 from its detection level of 1.9 Jy on 1987 March with a possible period of a year. Figure 1 plots the 22GHz flux as a function of Julian date. We do not yet know whether the period will repeat. V778 Cyg also has shown variations in the intensity (by a factor of - 2) on a time scale as short as 15 hours. The water maser flux from EU And has decreased from its detection value of 8 Jy in 1986 November staying relatively weak at the 2-3 Jy level during the last year. We interpret both V778 Cyg and EU And as binaries, each with an M star component with a thick circumstellar shell and a C star component. The C star is brighter in the visual region where the system is classified whereas the M star is brighter at wavelengths > 5 μm. The circumstellar shell is the source of the strong silicate emission seen in the IRAS LRS spectra and of the water maser emission.
Realization of the Primary Terrestrial Reference Frame
Authors: Kosek W. , Kołaczek B.
Published: July 2016

The PTRF is based on 43 sites with 64 SSC collocation points with the optimum geographic distribution, which were selected from all stations of the ITRF89 according to the criterion of the minimum value of the errors of 7 parameters of transformation. The ITRF89 was computed by the IERS Terrestrial Frame Section in Institut Geographique National - IGN and contains 192 VLBI and SLR stations (points) with 119 collocation ones. The PTRF has been compared with the ITRF89. The errors of the 7 parameters of transformation between the PTRF and 18 individual SSC as well as the mean square errors of station coordinates are of the same order as those for the ITRF89. The transformation parameters between the ITRF89 and the PTRF are negligible and their errors are of the order of 3 mm.
Long-Period Perturbations in Terrestrial Reference Frames
Authors: Groten E. , Molodensky S.M. , Zwielich J.
Published: July 2016

Oceanic and fluid core effects inherent in polar motion and 1.o.d. -data were analyzed and related results are discussed in detail.

A new exact analytic solution to the hydrodynamic equations is obtained, which describes tidal motions at low frequencies in a homogeneous, incompressible, inviscid liquid core with arbitrary core-mantle topography. Some geophysical and astrometrical consequences of this solution are considered.

The numerical estimation of the deviations of the pole tide from the static one is obtained. A new hypothesis is proposed that the known interrelation between long-term amplitude and frequency variations in Chandler wobble may be attributed to the influence of turbulent friction of non-equilibrium pole tide.
Comparison between Astronomical and Geodetic Coordinates
Authors: Banni A. , Poma A. , Proverbio E. , Falchi E. , Resta F. , Sanna G.
Published: July 2016

A requirement for solving Earth rotation problems is the definition of a terrestrial reference system (or systems) and the determination of a terrestrial coordinate frame (or frames). In this context it is important to determine the positions of the observing sites and their temporal variations and establish the dependence of the observations on local conditions and observing methods.

In situ concurrent observations are therefore important. In this paper we report the results of a comparison between astronomical and geodetic coordinates derived from different observations at the Cagliari Observatory and the Carloforte latitude station.
Quasar Link Conditions for Hipparcos
Authors: Brosche P. , Ducourant C. , Galas R. , Geffert M. , Karafistan A.
Published: July 2016

Fictitious proper motioms of quasars and of their surrounding stars have been determined based on plates with an epoch difference of up to 90 years. From the fact that the true proper motions of the quasar are vanishingly small, we obtain conditions for the extragalactic calibration of the preliminary Hipparcos system. We present results for the fields of 3C 273, OQ 208, 3C 371 and 3C 390.3. With the data it is possible to achieve the link with random errors smaller than 0₺ 15 per century.
Deficiencies in the Model for the Celestial Motion of the Cep as Derived from a Goddard/VLBI Series of Pole Offsets From 1979 to 1989
Authors: Capitaine N. , Caze B.
Published: July 2016

A VLBI series of celestial pole offsets (designated as ERP(GSFC)90 R 01 in the IERS series of Earth Rotation Parameters) spanning 10 years has been used for deriving the corrections to the IAU constant of precession and to the main terms of the 1980 IAU series of nutation using the same method as Herring (1988) for constraining the corrections to the 9.3yr nutation and to the l8.6yr nutation in longitude. The estimated corrections have been found to be − 0.279ʺ/c ± 0.02 ʺ/c (formal error) for the IAU constant of precession and +3.13±0.15mas for the 18.6yr nutation coefficient in obliquity. A circular term with a radius of the order of 0.25mas at a period of 430 days has moreover been revealed in the residuals as obtained after applying the estimated corrections to the series. If such a circular term in the celestial motion of the pole is due to the free core nutation, its estimated period would correspond to a core flattening of 2.687×10−3, which is in good agreement with the one of 2.674×10−3 corresponding to the estimated amplitude of the retrograde annual nutation.
The Radio Reference Frame of the U.S. Naval Observatory Radio Interferometry Program
Authors: Eubanks T.M. , Carter M.S. , Josties F.J. , Matsakis D.N. , McCarthy D.D.
Published: July 2016

The U.S. Naval Observatory Navnet program monitors changes in the rotation of the Earth on a regular basis using radio interferometric observations acquired with telescopes in Alaska, Hawaii, Florida, West Virginia and, in the past, Maryland; other radio telescopes have also participated occasionally. These observations have been used to derive a radio interferometric celestial reference system, Navy 1990-5, using two years of dual frequency measurements from 24-hour-duration observing sessions. A total of 84 extragalactic radio sources, mostly quasars, have been observed by the Navnet program to date, of which 70 currently have source position formal errors of one milli second of arc or less. The root mean square of the difference between source position estimates from the Navnet data and an independently derived catalog using completely different data is less than one milli second of arc in both right ascension and declination after the adjustment of an arbitrary rotational offset between the two celestial reference frames.
Connection Between Non-Rotating Local Reference Frames by Means of the World Function
Authors: Gambi J.M. , Romero P. , Miguel A.San , Vicente F.
Published: July 2016

By means of the world function an approximate transformation showing the Riemann tensor between the Fermi coordinates associated to two non-rotating local reference frames is derived in a General Relativistic space-time. One of the observer’s world lines is resticted to be a time-like geodesic of the space-time, and the other is a time-like curve of a general character. The space-time where the transformation is evaluated is supposed to be of small curvature, and the calculations are carried out in a first order of approximation with respect to the Riemann tensor.
Testing the Astrometric Accuracy of the 2m Telescope of Rozhen Observatory after Changing the Prime Mirror
Authors: Shkodrov V. , Geffert H. , Pollas C. , Heudier J.-L. , Ivanova V.
Published: July 2016

The astrometric accuracy of the recent configuration of the (D=2m, f=16.5m) RC telescope of the Rozhen obesrvatory (Bulgaria) was tested. We compared x and y positions from a plate of the RC telescpe with positions obtained from a plate of the (D=0.7m, f=3m) CERGA Schmidt telescope at CERGA (France). The positions coincided on a level of 0.09 arcsec, which is caused mainly by the error of the measurements of the CERGA plate.
The Magnetic Sun from Different Views: A Comparison of the Mean and Background Magnetic Field Observations made in Different Observatories and in Different Spectral Lines
Authors: Demidov M. L.
Published: July 2016

A comparison is made of observational data on the mean magnetic field of the Sun from several observatories (a selection of published information and new measurements). Results of correlation and regression analyses of observations of background magnetic fields at the STOP telescope of the Sayan solar observatory in different spectral lines are also presented. Results obtained furnish an opportunity to obtain more unbiased information about large-scale magnetic fields of the Sun and, in particular, about manifestations of strong (kilogauss) magnetic fields in them.
A Rapidly Evolving Active Region NOAA 8032 observed on April 15th, 1997
Authors: Mathew Shibu K. , Ambastha Ashok
Published: July 2016

The active region NOAA 8032 of April 15, 1997 was observed to evolve rapidly. The GOES X-ray data showed a number of sub-flares and two C-class flares during the 8–9 hours of its evolution. The magnetic evolution of this region is studied to ascertain its role in flare production. Large changes were observed in magnetic field configuration due to the emergence of new magnetic flux regions (EFR). Most of the new emergence occured very close to the existing magnetic regions, which resulted in strong magnetic field gradients in this region. EFR driven reconnection of the field lines and subsequent flux cancellation might be the reason for the continuous occurrence of sub-flares and other related activities.
Twist of Magnetic Fields in Solar Active Regions
Authors: Zhang Hongqi , Tian Lirong , Bao Shudong , Zhang Mei
Published: July 2016

Extended abstract

In the solar atmosphere, the magnetic and current helicity have played an important role in the study of twisted magnetic field. Current helicity parameterh∥=B∥· (∇ ×B)∥and force free factorcan be used to analyze the distribution of twisted field (current helicity) in the photosphere (Seehafer 1990; Pevtsovet al.1995; Bao & Zhang 1998). Bao & Zhang (1998) and Zhang & Bao (1999) computed the photospheric current helicity parameterh∥for 422 active regions, including most of the large ones observed in the period of 1988–1997 at Huairou Solar Observing Station of Beijing Astronomical Observatory.

The calculated results (Pevtsovet al.1995; Abramenkoet al.1996; Bao & Zhang 1998) show that most current helicities in sunspot groups in the northern hemisphere show negative sign in the northern hemisphere, while positive in the southern hemisphere, which is consistent with Seehafer’s result (Seehafer 1990). The distribution of current helicity parameterh∥in active regions also shows the butterfly pattern through the solar cycle. And, less than 30% of the active regions do not follow the general trend (Zhang & Bao 1998).
Solar Energetic Particle Events at the Rise Phase of the 23rd Solar Activity Cycle Registered aboard the Spacecraft “INTERBALL-2”
Authors: Timofeev Vladislav , Starodubtsev Sergey
Published: July 2016

The experiment with 10K-80 aboard the INTER-BALL-2 (which detects protons with energies > 7, 27–41, 41–58, 58–88, 88–180 and 180–300 MeV) registered six events of the solar energetic particle (SEP) increase. These events are during the initial rise phase of the 23rd solar activity cycle. Solar flares with the SEP generation are accompanied by coronal mass ejection (CME). Here we analyze the dynamics of the differential energy spectrum at different phases of the SEP increase.
Relationship of Non-potentiality and Flaring: Intercomparison for an M-class Flare
Authors: Ambastha Ashok , Mathew Shibu K.
Published: July 2016

We have made an attempt to obtain relationship of magnetic shear and vertical currents in NOAA AR7321. Intercomparison of changes observed at several flaring and non-flaring sites associated with an M4/2B flare observed on October 26, 1992 is reported.
Properties of Flux Tubes and the Relation with Solar Irradiance Variability
Authors: Fligge M. , Solanki S. K.
Published: July 2016

At the solar surface the magnetic field is bundled into discrete elements of concentrated flux, often referred to as magnetic flux tubes, which cover only a small fraction of the solar surface. Flux tubes span a whole spectrum of sizes, ranging from sunspots to features well below the best currently obtainable spatial resolution.

Whereas sunspots have been well studied, our knowledge of the true brightness of small-scale magnetic features is hampered by the insufficient spatial resolution of the observations. A better understanding of the thermal and magnetic properties of these small-scale features, however, is crucial for an understanding of (climate-relevant) long-term solar irradiance variations.
Non-Radial Oscillations in an Axisymmetric MHD Incompressible Fluid
Authors: Narayanan A. Satya
Published: July 2016

It is well known from Helioseismology that the Sun exhibits oscillations on a global scale, most of which are non-radial in nature. These oscillations help us to get a clear picture of the internal structure of the Sun as has been demonstrated by the theoretical and observational (such as GONG) studies. In this study we formulate the linearised equations of motion for non-radial oscillations by perturbing the MHD equilibrium solution for an axisymmetric incompressible fluid. The fluid motion and the magnetic field are expressed as scalarsU,V,PandT, respectively. In deriving the exact solution for the equilibrium state, we neglect the contribution due to meridional circulation. The perturbed quantitiesU*,V*,P*,r*are written in terms of orthogonal polynomials. A special case of the above formulation and its stability is discussed.
Mechanism of Cyclically Polarity Reversing Solar Magnetic Cycle as a Cosmic Dynamo
Authors: Yoshimura Hirokazu
Published: July 2016

we briefly describe historical development of the concept of solar dynamo mechanism that generates electric current and magnetic field by plasma flows inside the solar convection zone. The dynamo is the driver of the cyclically polarity reversing solar magnetic cycle. The reversal process can easily and visually be understood in terms of magnetic field line stretching and twisting and folding in three-dimensional space by plasma flows of differential rotation and global convection under influence of Coriolis force. This process gives rise to formation of a series of huge magnetic flux tubes that propagate along iso-rotation surfaces inside the convection zone. Each of these flux tubes produces one solar cycle. We discuss general characteristics of any plasma flows that can generate magnetic field and reverse the polarity of the magnetic field in a rotating body in the Universe. We also mention a list of problems which are currently being disputed concerning the solar dynamo mechanism together with observational evidences that are to be constraints as well as verifications of any solar cycle dynamo theories of short and long term behaviors of the Sun, particularly time variations of its magnetic field, plasma flows, and luminosity.
The Enhanced Coronal Green Line Intensity and the Magnetic Field Gradients
Authors: Ramesh K. B. , Nagabhushana B. S. , Varghese B. A.
Published: July 2016

Extended abstract

Ramesh, Nagabhushana and Varghese (1999) have shown that the green line intensity enhancement does not depend entirely on the strength of the underlying spot magnetic field though the coronal intensity enhanced feature is almost sure to occur at the locations of sunspots with strong magnetic fields and at the locations of plages having larger areas. Presented here are the results of an analysis of intensity of green line emission and the active region magnetic signatures as seen in Stanford magnetograms.

The data base used in this study consisted of homogeneous data set (HDS) of 5303 Å green coronal intensity measured at position angle intervals of 5° on any given day from several stations (see Rybanský, 1975) and brought down to the common scale of Lomnicky Štit. Daily maps of sunspots, and Ca plages are then superposed on the green line intensity maps of the corresponding day. Resultant composite maps are then compared with the Stanford magnetograms published inSolar Geophysical Data.
Summary Lecture
Authors: Stenflo J. O.
Published: July 2016

This summary lecture makes no attempt to summarize what was actually said at the meeting, since this is well covered by the other contributors. Instead I have structured my presentation in three parts: First I try to demonstrate why the Sun is unique by comparing it with laboratory plasmas. This is followed by some personal reminiscences that go back a significant fraction of the century. I conclude in the form of a poem about this memorable conference in honor of the centennial anniversary of the Kodaikanal Observatory.
Theory of the Hanle Effect; Application to the Linear Polarization of the Helium Lines in Solar Prominences
Authors: Bommier V.
Published: July 2016

This paper presents the results of the calculation of the Hanle effect for two lines of Helium I (D3, line λ = 5876 Å, infrared line λ = 10 830 Å).
Interpretation of the Filament Depression at Millimetric and Centimetric Wavelengths
Authors: Raoult A. , Lantos P. , Fürst E.
Published: July 2016

The depressions at centimetric and millimetric wavelengths associated with the filaments are studied using already published maps as well as unpublished observations from the Effelsberg 100 m radio telescope of the M.P.I., Bonn. The study has been restricted to large Ha quiescent prominences of relatively simple shape, situated far from the limb and from active regions. The data has been reduced employing one method whose main characteristics are choice of a local quiet sun definition and avoidance of the unstable process of deconvolution.
Braided Structures Observed in Flare-Associated Hα Filaments
Authors: Gaizauskas V.
Published: July 2016

The motions of flare-associated filaments and prominences produce such large Doppler shifts that the morphology of these active phenomena cannot be studied without filtergrams taken in rapid succession at a number of wavelengths across the Hα line. It is therefore standard practice at the Ottawa River Solar Observatory (ORSO) to photograph single active regions through a Zeiss filter while the pass-band (0.25A) of the filter is stepped continously back and forth across the Hα line. A typical scan consists of 17 steps in the range Hα ± 1.4A and is completed in 42 seconds. Important by-products result from this procedure, especially when the seeing allows the full resolution (0.7 arc-sec) of the 25 cm objective of the ORSO photoheliograph to be realized. First, filtergrams taken outside the core of Hα (Δλ≥ 0.9A) reveal the bright photospheric network (Vrabec, 1971; Dunn and Zirker, 1973; Dravins, 1974) which is, within the resolution capabilities of this instrument, co-spatial with strong magnetic fields near photospheric levels. In active regions the photospheric network is enhanced in brightness and becomes plainly visible as an aggregation of interlocking cells of various sizes. These data supplement magnetograms which are still needed to identify polarities and to furnish quantitative measurements of magnetic flux. Second, the visibility of the multi-threaded fine structure of filaments is usually much improved at wavelengths displaced from the centre of Hα. Thus a single instrument can provide the spatial data for investigating the relationship between the fine structure of filaments and highly localized concentrations of strong photospheric magnetic fields.
Activated Prominences; Mechanisms for Activation and Eruption
Authors: Spicer D.S.
Published: July 2016

A possible relationship between the hot prominence transition sheath, increased internal turbulent and/or helical motion prior to prominence eruption and the prominence eruption (“disparition brusque”) is discussed. The associated darkening of the filament or brightening of the prominence is interpreted as a change in the prominence’s internal pressure gradient which, if of the correct sign, can lead to short wavelength turbulent convection within the prominence. Associated with such a pressure gradient change may be the alteration of the current density gradient within the prominence. Such a change in the current density gradient may also be due to the relative motion of the neighbouring plages thereby increasing the magnetic shear within the prominence, i.e., steepening the current density gradient. Depending on the magnitude of the current density gradient, i.e., magnetic shear, disruption of the prominence can occur by either a long wavelength ideal MHD helical (“kink”) convective instability and/or a long wavelength resistive helical (“kink”) convective instability (tearing mode). The long wavelength ideal MHD helical instability will lead to helical rotation and thus unwinding due to diamagnetic effects and plasma ejections due to convection. The long wavelength resistive helical instability will lead to both unwinding and plasma ejections, but also to accelerated plasma flow, long wavelength magnetic field filamentation, accelerated particles and long wavelength heating internal to the prominence.
Models of Structure and Dynamics of Prominences
Authors: Anzer U.
Published: July 2016

The discussion in Working Group1was centered around 3 theoretical models. The participants were well aware of the fact that these idealized models have only limited value towards our goal of understanding the complex physical phenomena of quiescent prominences. We used these models mainly as a common basis for our discussion. The models, shown in Figure 1 are all 2-dimensional and only cross-sections normal to the long axis of the prominence are drawn. They are based on different magnetic field configurations. In all 3 models currents flow inside the prominence giving rise to a Lorentz-force which keeps the material from falling freely towards the surface of the Sun. Due to horizontal motion parallel to the prominence of the foot points of opposite polarity a magnetic field normal to the plane drawn will be induced. This then implies additional currents in the corona surrounding the prominence. Note that those field lines in the Kuperus and Raadu model which are open cannot maintain any shear and therefore must lie in the plane. The circular lines in the model of Malville result from a projection of helical field structures.
The Chaotic Motion of the Solar System
Authors: Laskar J.
Published: July 2016

In a previous paper (Laskar, Nature, 338, 237-238), the chaotic nature of the solar system excluding Pluto was established by the numerical computation of the maximum Lyapunov exponent of its secular system over 200 Myr. In the present an explanation is given for the exponential divergence of the orbits: it is due to the transition from libration to circulation of the critical argument of the secular resonance 2(g4−g3)−(s4−s3) related to the motions of perihelions and nodes of the Birth and Mars. An other important secular resonance is identified: (g1−g5)−(s1−s2). Its critical argument stays in libration over 200 Myr with a period of about 10 Myr and amplitude from 85° to 135°. The main features of the solutions of the inner planets are now identified when taking these resonances into account. Estimates of the size of the chaotic regions are determined by a new numerical method using the evolution with time of the fundamental frequencies. The size of the chaotic regions in the inner solar system are large and correspond to variations of about 0.2 arcsec/year in the fundamental frequencies. The chaotic nature of the inner solar system can thus be considered as robust against small variations of the initial conditions or of the model. The chaotic regions related to the outer planets frequencies are very thin except for g6 which present variations sufficiently large to be significant over the age of the solar system.
On Instability Leading to Chaos in Dynamical Systems
Authors: Saha L.M.
Published: July 2016

Instability of orbits in dynamical systems leading to chaos has been reviewed briefly. Stability criteria for some unimodal mapping which provide various periodic regimes during the period doubling bifurcations has been discussed in detail. Stability conditions are reviewed for standard map (or Chirikov-Taylor map), and results obtained for range of values of the non-linear parameter appearing in the map have been studied. Strange attractor has also been discussed.
Stochastic Instability in Gravitating Medium
Authors: Rozgacheva Irina K.
Published: July 2016

Our Universe has probably a space-time with a humpy metric. The space-time has nondegenerate (unequal) geodesics. The Universe is weakly inhomogeneous. The nonstationary inhomogeneities (humpies) of gravitational field change the redshift of any astronomical object - change brightness (Sachs-Wolfe’s effect), and change trajectories of photons. The latter effect is considered here. It is found that a theorem on the null geodesics are instable in the Universe with positive density contrasts. Photons must lose an information of their initial directions of propagation. So such radiation as the Microwave Background Radiation must seem uniform in the Universe.
Dynamical Evolution of Stellar Clusters and Associations in the Field of Tidal Forces of the Galaxy
Authors: Kozhanov T.S.
Published: July 2016

The equations of motion of the star-members of the cluster averaged on the elliptic orbits are obtained. These equations take into account the tidal forces of the Galaxy. The generalization of the Lagrange-Jacobi equation and Sundman inequality for non-classical scheme of the many-body problems is revised. The dynamical evolution of the moment of inertia is studied. Some theorems which determine the type of the star motion in the cluster are formulated.
Roche Instability in Ejecting Stellar Systems
Authors: Narasimhan K.S.V.S. , Alladin S.M.
Published: July 2016

We consider a small stellar system ejected from the interior of a bigger one. The two systems are represented by unequal Plummer models and energy changes in them are derived analytically under the impulse approximation. These are used to obtain the conditions for the Roche instability of the systems. For systems greatly differing in dimension, the density ratio of the two systems is a useful parameter for specifying the Roche limit for the disruption of the smaller system and the mass ratio is a meaningful parameter for specifying the Roche limit for the disruption of the bigger system. Density ratios and mass ratios at Roche limit are given for both systems for various scale-length ratios of the two systems.
Dynamics of the Antonov-Nuritdinov Planar Galaxy Model
Authors: Sridhar S.
Published: July 2016

A time dependent solution of the collisionless Boltzmann equation (CBE) in two space dimensions first given by Antonov and Nuritdinov is discussed further. The solution is self consistent with a quadratic potential and represents a generalised Freeman bar characterised by 10 parameters. Because of two conserved quantities, they form an 8-dimensional phase space. Geometric and group theoretical aspects of this dynamical system are discussed. Systems of this type can show chaotic oscillations in general. This study raises interesting general questions about time dependent solutions of the CBE.
Long-Term Predictions for Highly Eccentric Orbits
Authors: Ferrándiz José M. , Sansaturio M. Eugenia , Vigo Jesús
Published: July 2016

Predictability in orbital behaviour of artificial satellites depends on several factors: the accuracy required, the particular dynamical models formulated, the sets of variables chosen to describe them, the numerical or analytical techniques used and, specially, the specific trajectories to be established. In this paper we address the problem of predictability for highly eccentric satellites with (J2 + J22)-perturbation, by using numerical techniques to integrate the equations of motion when expressed in different sets of regular variables.
Fragility in Cosmology and Astrophysics
Authors: Tavakol R.K.
Published: July 2016

The theoretical framework adopted in astrophysics and cosmology, in both modelling and the analysis of the observational data, is often implicitly assumed to be that of structural stability. Here, in view of some of the recent results in dynamical systems theory, it is argued that such a framework cannot be assumed a priori and that the fragility framework may instead turn out to be the appropriate framework for the study of certain phenomena in the astrophysical and the cosmological settings. This is motivated by a number of examples from cosmology and a brief discussion of some of the potential domains of its relevance in astrophysics.
The Present Status of the Munich Dust Counter Experiment on Board of the Hiten Spacecraft
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

The Munich Dust Counter (MDC) is a scientific experiment on board the MUSES-A mission of Japan measuring cosmic dust. The satellite HITEN of this mission has been launched on January 24th, 1990 from Kagoshima Space Center. Here the present status of the MDC experiment is summarized. The number of dust particles measured so far is presented together with first and preliminary results of flux calculations and spatial as well as directional distributions of cosmic dust particles measured until July 25, 1990. A clear evidence of particles coming from the inner solar system (beta-meteoroids) already has been found. These are compared to particles coming from the apex direction.
Ultraviolet-Induced Amorphization of Cubic Ice and its Implication for the Evolution of Ice Grains
Authors: Kouchi A. , Kuroda T.
Published: July 2016

We found that cubic ice is transformed below 70 k to amorphous ice by ultraviolet irradiation, whereas no change in structure is observed at temperatures above 70 K, regardless of the irradiation time. Experimental results can be interpreted by theoretical consideration of nucleation and growth of cubic ice in amorphous ice. We also discuss the evolution of ice grains in space on the basis of the experimental results.
Simulation in Laboratory of Solid Grains Present in Space
Authors: Colangeli L. , Bussoletti E. , Mennella V.
Published: July 2016

Laboratory data on cosmic dust analogue materials are compared with recent results obtained by means of spectroscopy and mass spectrometry on cometary dust, meteorites and interplanetary dust. Their actual chemical and physical properties can be further clarified, as well as possible links with interstellar dust.
Structures of Amorphous Silicate Dusts Simulated by Molecular Dynamics Method
Authors: Tsuchiyama A. , Kawamura K.
Published: July 2016

Atomic structures of amorphous silicate dusts with the MgSiO3composition were simulated by molecular dynamics method as a function or the dust density based on the assumption that the density corresponds to cooling rate of dust formation. The SiO4tetrahedra are more polymerized with decreasing density, suggesting phase separation between SiO2-rich and MgO-rich components in less dense dusts formed by rapid condensation. A mode of atomic vibration probably due to the Si-0 bending is different in the amorphous silicates with different densities. This may cause changes of the 20 μm bands of IR spectra of silicate dusts with different cooling rates.
Measurement of Far-Infrared Absorption for Amorphous Silicates between 27 and 400 μm
Authors: Koike Chiyoe , Shibai Hiroshi
Published: July 2016

The far-infrared extinction of various silicates was measured in the 27 - 400 μm range of wavelength. The SiO2content of our samples distributes between 45 and 100 weight (wt.)%. There is no distinct absorption band in the far-infrared region and the extinction decreases in proportion toλ−1.4.
Interplanetary Dust Close to the Sun
Authors: Mann Ingrid
Published: July 2016

The optical and infrared brightness of the Fraunhofer-corona is produced by light scattering at the zodiacal dust particles and by their thermal emission (see Koutchmy and Lamy 1985). It is modelled within the ecliptic (4 Ro≤ ε ≤ 15 Ro)taking into account investigations of the global zodiacal dust cloud due to remote sensing and in situ experiments. The input of near solar dust to the corona brightness is discussed.
Future Observation of the F-Corona with the Lasco Coronograph Space Experiment
Authors: Lamy P.L. , Llebaria A. , Maucherat A. , Koutchmy S. , Giovane F.
Published: July 2016

The Wide-field White Light and Spectrometric Coronograph (LASCO) to be flown on SOHO in 1995 will observe the corona from just above the limb at 1.1 out to 30 solar radii (Ro). In addition to the fundamental problems of coronal physics (heating of the corona, acceleration of the solar wind, coronal transients), the scientific objectives incorporate the distribution and properties of dust particles including those released from sun-grazing comets, and interactions of coronal plasma with the dust.