bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Neutrinos from Supernova 1987A
Authors: Chiu H. Y. , Chan K. L. , Kondo Y. 
Published: July 2016

W ehave developed a time-energy correlation method1 to bring forth the mass signature from Supernova 1987a neutrino observations, if the neutrino has any mass at all. This method is particularly effective in analyzing data sets with a small number of events, such as the Kamiokande II2 and the IMB3 observations of neutrino bursts from Supernova 1987A. The time dispersion Δt12 between two simultaneously emitted neutrinos of energies E1, E2 (E1 < E2 ) and a neutrino mass energy mv is given by:where L is the distance of the source and c is the velocity of light. Conversely, Eq.(1) can also be used to establish time relationships of detected neutrinos and the existence of a mass. Applying Eq.(1) to all pairs for which real values of mv (called the correlation mass) are obtained from the observed Δt12, E1, E2, the existence of a cluster of pairs with essentially the same mass mv will indicate (a) many pairs of neutrinos were emitted within a narrow time window, and (b) the existence of a mass at mv. If a group of neutrinos were emitted within a narrow window, these groups will show a strong time correlation. Thus, this method of analysis does not impose a condition for the emission mechanism - rather, if the result of this analysis indicates the existence of a mass, there must exist a time correlation among the neutrinos.
SN1987A and Constraint on the Mass and Lifetime of Tau Neutrinos
Authors: Takahara Mariko , Sato Katsuhiko 
Published: July 2016

Recently it has been suggested that neutrinos have nonvanishing mass from both experimental and theoretical investigations. Accelerator experiments and cosmology, however, impose the constraints on mass mv and lifetime τv of vτ (see Fig. 1). As we showed in the previous paper [1], supernova explosion also imposes the stringent constraint on them. The purpose of this paper is to investigate the constraint imposed on mv and τv of vτ from SN1987A.Tau neutrinos are emitted from the central part of the iron core together with the electron neutrinos because they are also in thermal equilibrium with matter there.
Collapse of the Neutron Star Induced by Phase Transitions and Neutrino Emission from SN1987A
Authors: Takahara Mariko , Sato Katsuhiko 
Published: July 2016

The neutrino burst from SN1987A were detected by KAMIOKANDE and also IMB in February this year. The neutrino events detected by KAMIOKANDE were clustered into three bunches; event number 1-5, 7-9, 10-12. The first two bunches of the neutrino events can be understood by the standard scenario of supernova explosions.However, it is very difficult to explain the last bunch of the neutrino events by the standard scenario, especially the total energy of the neutrinos and the radius of the neutrino sphere; it is necessary at least several times of 1052 ergs to explain the total energy of the last three events. In order to explain this energy, we must consider the non-standard mechanism of the neutrino emission.
The Statistical analysis of Supernovae
Authors: Li Zongwei 
Published: July 2016

Due to the growing interest in the SN(supernovae) phenomenon in recent years, and to large amount of data which has been accumulating lately, there is now a need for a new publication in which to find all the essential data on SNe and their parentgalaxies. A revised 568 supernova catalogue has published by Barbon et al (1984).The paper supplements 65 SNe, discovered since 1984 up to update, and some statistical studies were completed.The first two comprehensive lists of SNe were published by Zwicky(1958, 1965) and included the 54 and 111 objects respectively reported up to 1956 and 1962. A more complete list was issued by Zwicky(1964), 154 SNe is inclused.
Radio Patrol Camera for Supernovae Search
Authors: Daishido T. , Asuma K. , Inoue S. , Nishibori K. , Ohara H. , Komatsu S. , Nagane K. 
Published: July 2016

Zwicky started extragalactic supernovae patrol using 10 inch Schmidt camera about fifty years ago. After that the research of supernovae was accelerated, because the wide view of the Schmidt camera made it possible to watch large field of the sky. The key technology of the Schmidt camera was its sophisticated optical system.Anticipated next supernova in our Galaxy may be undetectable by the optical instrument due to the Galactic extinction. However, supernovae are now known to be intense radio sources after a year or so of the explosion. Even if the positions are beyond the Galactic center, the radio supernova could be observed using middle size radio telescope.
Wind characteristics of the 07 n star HD 217086 in the Cep OB 3 association
Authors: Perinotto Mario , Panagia Nino 
Published: July 2016

AbstractThe 07 n star HD 217086 which provides the ionization of the H II region S 155 A and is the brightest member of the Cep OB 3 association, has been observed in the ultraviolet with IUE. From an analysis of the UV spectra we determine a terminal velocity of 3560 ± 100 km s-1 and a mass loss rate of . A comparison is made with the stars of similar spectral type.
Mass loss rates of OB stars derived from infrared observations
Authors: Tanzi E.G. , Tarenghi M. , Panagia N. 
Published: July 2016

In this paper we report briefly on a study of the mass loss of early type stars in the infrared. Up to now near infrared (1.25 - 4.8 μ ) broad band photometry of 70 southern OB stars of various luminosity class has been secured. Program stars have been selected, among those bright enough in the infrared to give a suitable photometric accuracy, in order to cover a wide range of spectral types (Fig. 1).37 stars are found to exhibit emission in excess over a blackbody photospheric continuum, which is interpreted in terms of gas ejected in the form of an accelerated wind. By means of model calculations the corresponding mass loss rates are derived. The obtained values compare well with those determined indipendently by various Authors for stars in common. Our data show that mass loss rates increase with luminosity and are a decreasing function of surface gravity.
On the stellar gravity and effective temperature dependence of the ratio of
terminal to escape velocities in stellar winds
Authors: Carrasco Luis 
Published: July 2016

Contrary to the results of some investigators, the ratio of terminal to escape velocities (V∞/Vesc) observed for the winds in early-type stars is found to be linearly correlated with log Γ - Γ being the ratio of stellar to Eddington's luminosities.Although the determination of terminal velocities for O-type main sequence stars from edge velocity information may be somewhat questionable (Lamers, 1980). The determined values for the β and γ fitting parameters for the observed profiles by Conti and Garmany (1980) are tipically on the order of one for these stars. Hence, from the grid of profiles by Castor and Lamers (1979), we estimate that at most a 10% error is introduced by adopting the edge velocities as representative values of the terminal velocities of main sequence O-type stars.
Observational evidences of stellar wind
Authors: Tarafdar S.P. 
Published: July 2016

AbstractObservations mainly from the IUE Spectra of HD 152236 (Blla) have been used to provide support to the various aspects of the theory of stellar wind (SW) and its interaction with the interstellar medium (ISM). Lines arising from excited levels connected radiatively to the ground level tend to be more frequent and/or strong compared to those arising from radiatively forbidden levels of similar excitation as expected from radiatively driven wind. The outward velocity from shifts of Si III lines from different excited levels increases steeply with decreasing excitation energy in agreement with theories. Absorption lines (P-Cygni like) of C II, Al II, Si II and Mg II shifted shortward by about 300 km s-1 suggest an expanding shell around the star. As this velocity is smaller than the terminal velocity (880 km s-1) the circumstellar shell may have been formed as a result of interaction of SW with ISM.
Photospheric molecular line profiles in cool stars
Authors: Ridgway S.T. , Friel E.D. 
Published: July 2016

AbstractSpectral lines of the ΔV=2 rotation vibration bands of CO are well suited for study of photospheric motions and the mass ejection process in cool stars. We have obtained high spectral resolution (1.8 km/sec) and high signal-to-noise (>102) line profiles for a selection of K and M giants. These profiles are being studied for evidence of gas motions in the photosphere and near circumstellar regions.
Line formation in the wind of Alpha Cygni
Authors: Kunasz P.B. , Praderie F. 
Published: July 2016

AbstractWe summarize the results of recent IUE observations of the spectra of α Cygni and discuss possible explanations for the Doppler-shifted pure absorption profiles in the resonance lines of the singly ionized metals. The results of detailed modeling for MgII λ 2795, 2802 are presented, and discussed in the context of observations of α Cyg in the radio, infrared, visible, ultraviolet and X-ray parts of the spectrum.
Radiative wind acceleration in early type stars
Authors: Panagia N. , Macchetto F. 
Published: July 2016

AbstractThe processes of radiative acceleration of stellar winds in OB stars by single and multiple photon scattering are considered. Single scattering can be the dominant accelerating process for stars later than B2 (Teff < 2 x 104 K) and can account for terminal velocities up to 500 – 1000 km s-1 . Multiple scattering of photons in the approximate range 200 – 500 A provides additional wind acceleration for stars earlier than B2 to reach terminal velocities of up to 2000 – 4000 km s-1 A systematic increase of the terminal velocity as a function of the effective temperature is predicted. Observational data confirm this expectation quite well.
The fluctuation theory of the stellar mass loss
Authors: Andriesse C.D. 
Published: July 2016

That we cannot give a justification – or sufficient reasons – for our guesses does not mean that we may not have guessed the truth.K.R. PopperIf studied in detail, the mass flows from the stars appear to be variable. “Mere inspection of solar wind data reveals large variations on a time scale of several days” (Hundhausen, 1972). Also, “it is obvious that mass loss from hot stars is not a stationary phenomenon but that variations on short timescale occur” (de Jager et. al., 1979). And a cool supergiant has “a photosphere fluctuating in both brightness and radial velocity, (and) an expanding chromosphere … uncoupled from motions in the photosphere” (Goldberg, 1979).
Mass loss and evolution of massive stars
Authors: Chiosi C. 
Published: July 2016

In the past few years both growing observational evidence and theoretical understanding have shown that mass loss by stellar wind is a common occurrence in the evolutionary history of many types of star. Recent reviews on the subject may be found in Conti (1978), Cassinelli (1979), Conti and Mc Cray (1980), Hutchings (1980a), de Loore (1979, 1980) and Sreenivasan (1979).Therefore, in this paper we will concentrate only on those observational and theoretical aspects of the problem that demand further investigation.
Is this diagramme an argument for binary orbital evolution due to mass-loss?
Authors: Dommanget J. 
Published: July 2016

AbstractIn 1963, a diagramme has been established by the author, for visual and spectroscopic binaries, showing the existence of a real correlation between total mass and eccentricity.The consideration of an up-dated material leads to-day to an identical diagramme confirming the reality and the stability of the mentioned correlation.This diagramme is discussed with the assumption of a substantial secular mass-loss of the components of the considered binaries.
Nova AQL 1918: a nude old nova
Authors: Selvelli P.L. , Cassatella A. 
Published: July 2016

AbstractIUE observations at high and low resolution of Nova Aql 1918 show neither evidence of outflow nor the presence of nebular lines. This indicates that the shell ejected at the time of the outburst and surrounding the system for many years (Mustel and Boyarchuck, 1970) has by now disappeared.The high excitation spectrum presents rapid variations in the far UV and eclipse effects in the near UV that seem well correlated with the orbital phase.The observations can be interpreted in terms of phenomena occurring in or near the accretion disk surrounding the white dwarf. However, the small inclination of the orbital axis raises serious problems in trying to model the system.
Full-Disk Observations of Solar Oscillations from the Geographic South Pole: Latest Results
Authors: Grec Gérard , Fossat Eric , Pomerantz Martin A. 
Published: July 2016

AbstractThis paper presents the latest results obtained from the analysis of the full-disk Doppler shift observations obtained at the geographic South Pole in 1981. About 80 normal modes of oscillation (l = 0–3) have now been identified. Their frequencies range from 1886 μHz (l = 1, n = 12) to 5074.5 μHz (l = 2, n = 35), and their amplitudes are as low as 2.5 cm s–1. Amplitude modulation occurs with periods of 1–2 days, and the individual oscillations appear to be excited randomly and independently. In cases where other groups have observed some of the modes identified by us, the agreement in frequency is good.
Spectral-Spatial Analysis of Wave Motions in the Region of Temperature Minimum of the Sun’s Atmosphere
Authors: Merkulenko V.E. , Polyakov V.I. , Palamarchuk L.E. , Larionov N.V. 
Published: July 2016

AbstractA spectral-spatial analysis is made in the region of temperature minimum of the Sun's atmosphere. Filtergrams in the Ba II 4554 + 0.05 Å line have been used. The wavelengths corresponding to the sequence of peaks on the spectrum are in close agreement with those theoretically calculated by Ulrich and Rhodes (1977) for five-minute oscillations. We thus have good cause to surmize that the observed oscillations in the region of temperature minimum pertain to the p-mode class of general oscillations of the Sun, the main fraction of their energy falling on the period of 300 s.
Is There an Oblique Magnetic Rotator Inside the Sun?
Authors: Isaak G.R. 
Published: July 2016

AbstractThe size of the rotational splitting recently observed (Claverie et al., 1981) is correlated with the 12.2d variation in the measurements of solar oblateness observed by Dicke (1976) and implies a convection zone of depth of 0.1 Rʘ. The near equality of amplitudes of global velocity oscillations (Claverie et al, 1981) of the various m components of the l = 1 and l = 2 modes as seen from the Earth viewing the Sun nearly along the equator is unexpected for pure rotational splitting. It is suggested that a magnetic perturbation is present and an oblique asymmetric magnetic rotator with magnetic fields of a few million gauss is responsible. A more detailed account was submitted to Nature.
Derivation of the Amplitude Equations of Acoustic Modes of an Unstable Semi-Infinite Polytrope
Authors: Poyet Jean-Pierre 
Published: July 2016

AbstractThe coupling of non-radial pulsations and convection is studied on a simple example: an unstable semi-infinite polytrope. An expansion is proposed and the equations that should describe correctly the pulsations are isolated. The additional complications of the real solar case are discussed at the end.
Adiabatic Oscillations of a Differentially-Rotating Star. Second-Order Perturbation Theory
Authors: Vorontsov S. V. 
Published: July 2016

AbstractPerturbation theory is developed for calculating the influence of slow differential rotation on the adiabatic nonradial modes of stellar oscillations. The effects of Coriolis forces and ellipticity are analysed simultaneously using the perturbation technique for Hermitian operators which is developed up to second order in eigenvalues and to first order in eigenvectors.
Stellar 5 min Oscillations
Authors: Christensen-Dalsgaard Jørgen , Frandsen Søren 
Published: July 2016

AbstractEstimates are given for the amplitudes of stochastically excited oscillations in Main Sequence stars and cool giants; these were obtained using the equipartition between convective and pulsational energy which was originally proposed by Goldreich and Keeley. The amplitudes of both velocity and luminosity perturbation generally increase with increasing mass along the Main Sequence as long as convection transports a major fraction of the total flux, and the amplitudes also increase with the age of the model. The 1.5 Mʘ ZAMS model, of spectral type F0, has velocity amplitudes ten times larger than those found in the Sun. For very luminous red supergiants luminosity amplitudes of up to about 0ṃ.1 are predicted, in rough agreement with observations presented by Maeder.
Helioseismology in the Future
Authors: Bonnet R.M. 
Published: July 2016

AbstractWe review the observables of helioseismology that can contribute to our knowledge of the physical conditions in the solar interior. We discuss the limitations which presently prevent helioseismology from reaching its ultimate goal. We finally present a list of projects which either are already underway or that are planned for the near future, and we conclude by showing the crucial role that space observations may play in the future.
Results From Optical and UV Stellar Flare Spectroscopy
Authors: Giampapa Mark S. 
Published: July 2016

ABSTRACTOptical and ultraviolet spectroscopy can enable the assessment of the physical conditions characterizing a stellar flare atmosphere and thereby potentially elucidate the possible radiative and hydrodynamic transport mechanisms operative during stellar flares. In this review, I present illustrative examples of the spectroscopic diagnostic techniques that can be applied to the analysis of stellar flare spectroscopic data and the resulting inferences concerning stellar flare properties for M dwarf flare events.
IUE Spectra of The by Dra/Flare Star AU Mic
Authors: Butler C.J. , Andrews A.D. , Doyle J.G. , Byrne P.B. , Linsky J.L. , Simon T. , Marstad N. , Rodonò M. , Pazzani V. 
Published: July 2016

A coordinated series of ground-based optical and IUE observations of BY Dra variables was undertaken to follow the spectral variation of these stars over one cycle. In the first series 20 LWR and 19 SWP trailed spectra were taken of AU Mic over a three day period 4-6 August 1980 .In Figure 1 we show the mean integrated fluxes for the strong emission lines in the SWP spectra of AU Mic over the observed phase interval of 0.14 to 0.8 together with an approximate V light curve determined by the FES on IUE. From comparison of the emission line intensities and FES magnitudes in Figure 1 several points emerge.
RS CVn STARS: Photospheric Phenomena and Rotation
Authors: Catalano S. 
Published: July 2016

ABSTRACTThis review presents a summary of observed photospheric phenomena on RS CVn stars: the amplitude, shape, evolution and migration rate of the photometric wave in relation to the rotational and orbital motion.The main points considered are: 1) the activity level (maximum amplitude, short and long timescale variability) versus rotation period; 2) the activity cycles as inferred from changes in the wave migration rate and direction and from the variation of its amplitude; 3) the detection of differential rotation; 4) the connection between the orbital period variation and activity.
RS CVn Systems: The High Energy Picture
Authors: Charles P.A. 
Published: July 2016

AbstractThe discovery of X-ray emission from RS CVn systems by HEAO-1 and subsequent surveys by the Einstein Observatory have shown that these close binaries exhibit greatly enhanced coronal activity. Here we review the 3 main observational areas: (1) results of the X-ray surveys of RS CVn systems and other late-type stars which indicate how the X-ray luminosity is correlated with the binary period (and hence stellar rotation) and other coronal activity indicators. This will be discussed in the context of scaled models of the solar corona; (2) X-ray spectroscopy of the most active systems which show multitemperature spectra and line emission consistent with solar abundances of the heavy elements; (3) observations of X-ray “flare-type” activity that has been associated with several RS CVn systems.
Basic Parameters Determining X-Ray Emission Level in Stars of Spectral Type Later than F5
Authors: Paternò Lucio , Zuccarello Francesca 
Published: July 2016

This is a merely exploratory search for estimating the importance of those stellar parameters which we believe to be relevant to the X-ray emission from stars possessing outer convective envelopes.Belvedere et al.(1981,1982) have shown that a mechanism which converts magnetic into thermal energy is plausible for explaining the X-ray emission level in late type main sequence and giant stars. One of the main conclusions of their work is that the average surface X-ray flux Fx depends on the square of the average surface magnetic field strength B. The surface magnetic activity,in stars possessing outer convective envelopes, is likely due to the interaction of rotation with convection which produces both differential rotation (Belvedere et al. 1980a) and dynamo action by the α-effect (Belvedere et al. 1980b).Therefore we would expect that the level of magnetic field intensity depends on star's rotation Ω and the depth of the convection zone(c.z.) D,because both parameters are very important in determining the strength of the interaction.
Theory of the Libration of the Moon
Authors: Dubois-Moons M. 
Published: July 2016

AbstractThe paper presents a new theory of the libration of the Moon, completely analytical with respect to the harmonic coefficients of the lunar gravity field. This field is represented through its fourth degree harmonics for the torque due to the Earth (the second degree for the torque due to the Sun). The Moon is assumed to be rigid and its orbital motion is described by the ELP 2000 solution (Chapront and Chapront-Touzé 1981) for the main problem of lunar theory with planetary perturbations and influence of the non-sphericity of the Earth. Comparisons with other theories (Migus 1980 and Eckhardt 1981) are also presented.
The JPL “Long Ephemeris”, DE102/LE51
Authors: Standish E. Myles 
Published: July 2016

AbstractA number of applications exist in astronomical research for planetary and lunar ephemerides covering an extended length of time. This paper discusses such a set of ephemerides, DE102/LE51, produced at JPL, covering the time 1411 B.C. to 3001 A.D. The ephemerides are dynamically self-consistent, in that the equations of motion were integrated simultaneously. They also represent the most accurately known positions covering such a time span. They have already been used by a number of different users in a variety of different applications.
Stability and Bifurcations of Symmetric Periodic Orbits in the Restricted
3-Body Problem
Authors: Milani A. 
Published: July 2016

AbstractThe continuation of symmetric periodic orbits can be described in terms of “symmetry functions”; the branching of the zero-level lines in a neighbourhood of a critical point gives rise to the transition from “first kind” to “second kind” periodic orbits. When the families are parametrized with the Jacobi integral, the bifurcations can be described as “catastrophes” of the generating functions. However bifurcations of higher order are more complex than the generic catastrophes with one parameter: both symmetric and asymmetric bifurcations occur.In this way the symmetric periodic orbits that do not have close approaches to the secondary body can be described in an analytic way and their stability can be deduced from simple bifurcation rules. However numerical experiments are required to determine the “natural termination” of the families.