bluuebunny/crossref_metadata_2025 huggingface dataset:
Results of a Cooperative Investigation of RY Scuti
Authors: Kumsiashvili M.I.
Published: July 2016

Some preliminary results are given of a cooperative investigation of the highly interesting radio object RY Set. From spectroscopic data the mass-ratio was found to be q=m2/m1 ≈ 3.3. An attempt to determine the helium content by model-atmosphere techniques has shown that the atmosphere of the primary component has a large helium excess; the star has every characteristic of a helium star formed by mass exchange in case B. The analysis suggests that RY Set may offer a rare chance to observe a massive system at the stage when "switching of the roles" is complete and a helium remnant with a hydrogen shell is beginning to develop the characteristics of a WR-star.
Spectroscopy and Optical/IR Photometry of the Cataclysmic Variable CPD-48° 1577
Authors: Wargau W. , Bruch A. , Drechsel H. , Rahe J. , Schoembs R.
Published: July 2016

The photometric variability of CPD-48°1577 in the optical and IR ranges is discussed. The structure and variation of prominent emission line profiles are investigated. An estimate of the distance is given.
Observations and Models of Some Neglected Southern Eclipsing Binaries
Authors: Buckley David A. H.
Published: July 2016

Results of a photometric investigation of some photoelectrically neglected, southern eclipsing binaries, are presented for GW Car, X Car, and RS Set. Light curve solutions obtained by the Wilson-Devinney and Wood synthetic light curve techniques are described.
Photometric and Spectroscopic Study of R CMa
Authors: Radhakrishnan K. R. , Sarma M. B. K. , Abhyankar K. D.
Published: July 2016

UVB Flight curves and spectrograms of R CMa obtained with the 48-inch telescope of Japal-Rangapur Observatory during 1980-82 have been used for deriving the eclipse and orbital elements as well as the absolute dimensions of the components. The primary is found to be a Main-Sequence F2V star of mass 1.52 M⊙ and the secondary a subgiant star of spectral type G8 and mass 0.20 M⊙ which fills its Roche lobe, in agreement with Kopal and Shapley (1956) results, Kopal (1959), or Sahade's (1963) results. From a consideration of the possible evolution of this system it is concluded that a large fraction of the original mass of the secondary is lost from the system. A study of the period changes indicates the possible presence of a third component of mass of about 0.5 M⊙ which is most likely to be an M dwarf.
Astronomy in Japan
Authors: Hayakawa Satio , Saito Mamoru
Published: July 2016

The research activity in Japanese astronomy is described, taking into account the social and historical background. A trend in the last two decades is shown by the numbers of papers in 13 branches of astronomy. Major research facilities and international collaboration programs are summerized. Future programs under consideration are briefly discussed.
Giant Equatorial Radio Telescope
Authors: Swarup G. , Hidayat B. , Sukumar S.
Published: July 2016

A giant radio telescope for observing galactic and extragalactic radio sources at metre wavelengths is proposed. By locating a parabolic cylindrical antenna at a site close to the Equator such that its axis lies parallel to earth's axis, it is possible to construct a large collecting area economically. The proposed instrument will be very powerful for studying compact and diffuse features of radio sources, monitoring their variability, recombination and deuterium line work, studies of interplanetary medium and pulsar search.
Asteroid Masses and Densities
Authors: Schubart Joachim
Published: July 2016

Before 1966, when Hertz (1966) published his first direct determination of the mass of Vesta, all our knowledge on asteroid masses was based on estimates. The masses of the first four minor planets resulted from the measured diameters by Barnard (1900) (see the paper by Dollfus in this volume) and from estimated mean densities. The diameters of the smaller objects were derived from their brightness and an estimate of their reflectivity (usually the reflectivity of the Moon was adopted). In 1901, Bauschinger and Neugebauer (1901) derived a value for the total mass of the first 458 asteroids. All the diameters were computed from the brightness with an assumed value for the reflectivity. The diameter of Ceres found in this way is very close to Barnard’s (1900) value. The mean density of the 458 asteroids was put equal to that of Earth, and their total mass resulted as 3 X 10-9 solar mass. Stracke (1942) used the same method with an increased material, but the addition of more than 1000 faint asteroids did not bring a significant change in the estimate of the total mass. The report on the McDonald asteroid survey (Kuiper et al., 1958) does not contain another estimate of the total mass of the asteroid ring, but it points to the possibility of a very rapid increase in the number of asteroids with decreasing absolute brightness. If this increase is strong enough, each interval of 1 mag in absolute magnitude can contribute the same amount to the total mass. In the range of magnitudes covered by the Palomar-Leiden survey (PLS) (van Houten et al., 1970), there are no indications for such a strong increase.
Summary on Orientations of Rotation Axes
Authors: Vesely Carl D.
Published: July 2016

To evaluate the precision of the previously determined coordinates of the rotation axes (table I) we should review the methods (originally developed for 433 Eros) and logic of the various authors. Table II contains pole coordinates of Eros and the sources of these data. A critical summary of the work will enable us to make some conclusions concerning the poles presented.

There is general agreement that greatest rotational amplitude is observed when an asteroid is viewed equatorially, and we can detect three approaches to the determination of the Eros pole: the micrometer position angles observed by van den Bos and Finsen (1931); the graphic presentations used by Watson (1937), Stobbe (1940), and Rosenhagen (1932); and the mathematical model developed by Krug and Schrutka-Rechtenstamm (1936). These initial attempts yielded only approximate values, but the approximations were sometimes refined by analytical methods.
Orbital Selection Effects in the Palomar-Leiden Asteroid Survey
Authors: Kresák L.
Published: July 2016

The selection effects appearing in the list of minor planet orbits based on the Palomar-Leiden survey are discussed. In addition to purely geometrical effects produced by the limitation of the survey in time and position, the arrangement of orbits by perturbations plays an important role. Some apparent differences from the orbits of brighter asteroids can be easily explained. As an example of the operation of the selection effects, it is shown that the asteroidal Jetstream believed to exist within the Nysa family is spurious.
Are Meteors a Tool for Studying the Asteroids? Or Vice Versa?
Authors: McCrosky R.E.
Published: July 2016

The bulk of the comments I made at the colloquium are to be found in two recent papers (McCrosky and Ceplecha, 1970; McCrosky et al., 1971). The following summary is offered in place of a full text.

Most interpretations of all meteor data rely on knowledge of the relationship (luminous efficiency) between mass and luminosity. Discussions of recent experiments made to determine the luminous efficiency are found in papers by Ayers et al. (1970) and Becker and Friichtenicht (1971). Faint meteor phenomena can be understood if the meteoroids are weak, low-density (pm ≈ 0.25 g/cm3) “fluff balls” such as can be expected on the basis of Whipple's comet model (Jacchia, 1955; Jacchia et al., 1967). Alternative explanations, not requiring low densities, have been offered. Jones and Kaiser (1966) propose thermal shock of strong, high-density material as a fragmentation mechanism. Allen and Baldwin (1967) and Baldwin and Allen (1968) have reanalyzed Jacchia's data in terms of phenomena observed in the laboratory in simulated reentry experiments. Here, a high-density meteoroid froths and thereafter behaves as a low-density body. They also revise the luminosity law to account for blackbody radiation of refractory material. McCrosky and Ceplecha (1970) show that neither of these alternative explanations can apply to large bodies and, using photographic observations of bright fireballs, they defend Jacchia's original proposal for all meteors.
The Martian Satellites
Authors: Singer S. Fred
Published: July 2016

The Martian satellites are some of the most interesting and accessible objects in the solar system, and therefore worth studying or even visiting. As small bodies, on the order of kilometers in diameter (see table I), they may have experienced no internal heating or volcanism, and could therefore be original condensations in the solar system. They may thus be the only remnants of the original planetesimals.

An additional point of interest is that they are the only satellites in the inner part of the solar system–Earth's Moon is generally assumed to be a sister planet. As such, their study could illuminate one of the important differences between the inner and outer parts of the solar system.
Sample-Return Missions to the Asteroid Eros
Authors: Mascy Alfred C. , Niehoff John
Published: July 2016

Of the many asteroids that are cataloged, selection of a target planetoid was narrowed to the Mars-crossing asteroids. The main belt and Trojan asteroids are much farther away and require longer voyage times and propulsive energy to accomplish sample returns. Within the Mars-crossing group, those asteroids were surveyed that have orbits inclined less than 15°, perihelia within 0.2 AU of Earth’s orbit (and therefore require less propulsive energy), and diameters greater than 1 km (to assist terminal observation and rendezvous). Eros was chosen as representative of this class.
Estimate of Particle Densities and Collision Danger for Spacecraft Moving Through the Asteroid Belt
Authors: Kessler Donald J.
Published: July 2016

The present lack of exact information about the distributions of asteroids and asteroidal meteoroids causes the largest uncertainty in the description of the interplanetary meteoroid environment between the orbits of Mars and Jupiter. Observed asteroids are inferred to have diameters from a few kilometers to a few hundred kilometers. The presence of these larger bodies suggests the presence of smaller, unobservable bodies. When asteroids collide, fragments are produced that eventually collide with other fragments. Because of this continuous collision process, much smaller asteroids most probably exist. Such asteroidal meteoroids, if present in sufficient number, could pose considerable danger to spacecraft.
Observations in the Asteroid Belt with the Imaging Photopolarimeter of Pioneers F and G
Authors: Kenknight C.E.
Published: July 2016

Astronomical measurements of the brightness, color, and polarization of light from solar system bodies at phases not visible from Earth are planned for Pioneers F and G. An imaging photopolarimeter (IPP) in the scientific payloads will make these measurements and produce line-scan color images of Jupiter. The IPP collects light with a 2.5 cm aperture telescope that is able to turn in the plane containing the spin axis. Data are taken in scans around the spin axis along a cone whose apex angle is periodically changed by stepping the telescope. The light is analyzed for polarization, divided into blue and red components, and detected by four photomultipliers having electron channel multipliers. Appendix A gives a summary of instrument characteristics.
Spectroscopy of Laboratory Plasmas
Authors: Burgess D. D.
Published: July 2016

Work under the heading of Laboratory Plasma Spectroscopy may be conveniently separated into three classes depending on the extent to which the interaction of the emitting atoms with their plasma environment is central to the investigation. Zero order, the longest established use of laboratory plasmas in connection with astrophysics, concerns the use of hot plasmas for the excitation, measurement, and identification of the spectra of highly-stripped ions. In such work the properties of the plasma itself are usually of secondary importance. In first-order, plasma spectroscopy is used to determine fundamental atomic data concerned with the interaction of an atom with a single particle, usually either a photon or an electron, i.e.: the determination of oscillator strengths and collision cross-sections. Finally, higher-order processes in which the plasma nature of the surrounding medium is most relevant concern the study of line-shapes, and related topics such as the excitation of satellite spectral features by plasma oscillations. Developments in plasma diagnostic techniques in the last five years have greatly extended the scope of the second and third categories and have yielded much astrophysically important information from laboratory studies. Recent advances in these areas are reviewed.
Plasma Polarization Shift of the Resonance Lines of Ionized Helium
Authors: Volonte S.
Published: July 2016

In a recent T-tube experiment, Greig et al. (1970) reported the observation of a blue shift of ~0.05 Å for the first member of the resonance series of ionized helium. This was explained as due to some polarization effect in the plasma (Berg et al., 1962; Griem, 1966) and a classical estimate allowing for quantum mechanical effects was presented.
Observation of Argon Lines at Normal Pressure in the Vacuum Ultraviolet
Authors: Müller D. , Vadla Ć. , Vujnović V.
Published: July 2016

A normal pressure arc having local thermal equilibrium, is a useful source for measurements of atomic parameters in the vacuum ultraviolet region (Boldt, 1970). However, it imposes severe difficulties if the spectral lines ending on low-lying levels should be observed. The reason is the absorption effective in cold and inhomogeneous gas layers intervening in the optical path between the homogeneous hot plasma column and the vacuum monochromator. Here a version of a cascade arc with a differential pumping system is described which makes possible the observation of argon resonance lines at 1067 and 1048 Å, considerably free of absorption. For this purpose it was found necessary to use a bored anode as a pumping port.
High Resolution Solar Spectra from 1780 to 1950 Å
Authors: McAllister Howard C. , Wolff Richard J.
Published: July 2016

Excellent spectrograms in the region from 1780 to 1950 ängströms were obtained from the flight of a high resolution spectrograph in an Aerobee 150 rocket at White Sands Missile Range on June 14, 1971. The instrument’s dispersing system, consisting of a 79 line mm-1 echelle crossed with a 1200 line mm-1 grating, was incorporated in a Czerny-Turner arrangement using spherical mirrors of one meter focal length. Spectral resolution was limited to 13 mÅ by a slit width of 25 μ. The plate factor was 0.5 Å mm-1. Spectra were recorded on Kodak type 101-01 film.
On the Interpretation of the Relative Intensities of the Solar XUV Lines of Lithium-Like Ions
Authors: Flower D. R.
Published: July 2016

The relative intensities of the 2s–2p and 2l–3l′ (l=0, l′= 1; l= 1, l′ = 0, 2) solar XUV lines of ions in the lithium isoelectronic sequence are sensitive to electron temperature because of the large energy separation of the 2p and 3/’ levels. Recent observations of these lines for three members of the sequence, O+5, Ne+7 and Mg+9 (Heroux and Cohen, 1971), consequently provide a potentially powerful means of studying the temperature structure of the upper chromosphere-corona transition region. These observations have been examined in the light of recent calculations of the electron excitation cross-sections for the relevant transitions (Flower, 1971). It is found that the observed intensity ratios are systematically greater than values calculated assuming that all the lines of a given ion are produced at essentially the same temperature, namely, the temperature for which the ionization equilibrium calculations of Jordan (1969) predict that emission in the lines is most highly favoured. Part of the discrepancy is removed if this assumption is dropped and the emission in each line is calculated separately before taking the ratio. These two calculations do not yield the same result because there is a high temperature tail in the ionization curve of the lithium-like ions which results in the transitions of higher excitation energy, the 2l–3l′ transitions, being enhanced relative to the 2s–2p transition. The unsatisfactory agreement between theory and observation could have important implications for current theories of the ionization equilibrium, but, before definite conclusions can be reached, further observations of the same type need to be made and remaining uncertainties in the cross-sections to be resolved.
Recent Spectroscopy of X-Ray Sources and Systems Related to Cataclysmic Variables: II
Authors: Crampton D. , Cowley A.P. , Hutchings J.B.
Published: July 2016

Spectroscopic observations of two very different objects are discussed: the first, SS433, is a wery massive binary system probably containing an unseen 0 or WR star and a black hole surrounded by a luminous precessing accretion disk (from which emanate spectacular relativistic jets); the second, GK Per, is a classical old nova consisting of a slightly evolved K2 star and an unseen white dwarf companion surrounded by an accretion disk which is less luminous than the K2 star.
On Evolutionary Models for SNI Progenitor Stars
Authors: Colvin Jeffrey D.
Published: July 2016

It has been proposed that the Type I supernova (SNI) explosion starts in a white dwarf (WD) star that is accreting mass from a companion star in a close binary orbit. Others’ computations have described this explosion, but how an accreting WD can ever become an SNI if it first ejects the accreted envelope in one or more nova outbursts is still unresolved. My calculations of WD evolution include the effects of mass accretion, convective mixing, nuclear burning, and gravitational settling. These calculations test the Starrfield, Truran, and Sparks (1981) proposal that at low accretion rates, settling of the CNO nuclei will lead to steady-state hydrogen burning, not nova outburst. The preliminary results of this study, consisting of two evolutionary sequences of an initially cool pure 12C 1.0 Mʘ WD show that nearly half of the carbon near the base of the accreted layer, initially of solar composition, gravitationally diffuses out in 2 x 105 years.
Physical Conditions Inside White Dwarfs and Type I Supernovae
Authors: Schatzman E.
Published: July 2016

After the first suggestion by Schatzman (1963) that accreting white dwarfs, close to the limiting mass, might be the progenitors of type I Supernovae, the problem was not studied until Schatzman (1974) described the competition between collapse dominated by beta decay, which would lead to neutron star formation and collapse dominated by nuclear reactions leading to stellar disruption.
Spin-Up and Magnetic Fields in DQ Her Stars
Authors: Lamb D. Q. , Patterson J.
Published: July 2016

We have carried out a detailed comparison of the spin-up behavior of the recently discovered faint long-period X-ray sources, using the accretion torque theory of Ghosh and Lamb. We confirm that these sources are degenerate dwarfs. We find that they have magnetic fields B ~ 1 x 106 G, an order of magnitude smaller than those of AM Her stars. On this basis, we predict that they will show significant polarization in the infrared.
Polarimetric Observations of Hydrogen Deficient Stars
Authors: Raveendran A.V. , Rao N. Kameswara , Deshpande M.R. , Joshi U.C. , Kulshrestha A.K.
Published: July 2016

Polarimetric observations of HD 30353, SU Tau, XX Cam, R Cr B,UV Cas, BD+13 3224,BD+10 2179 and HD 124448 are presented. The linear polarization of HD 30353 is found to vary appreciably at Hα over time scale as short as one day. It is also found that SU Tau shows significant variation in polarisation even at light maximum.
Preliminary Analysis of the Broad He I Emission Lines in R CrB
Authors: Surendiranath R. , Rangarajan K.E. , Kameswara Rao N.
Published: July 2016

During light minimum phase, R CrB shows a broad emission line spectrum of He I including λ10830, λ7065, λ7281, λ3889, λ6678 and λ3188. But λ5876 is very weak. The observed intensity ratios of I(λ3889)/I(λ5876) and I(λ7065)/I(λ5876) were greater than 1. The anomalous intensities of these lines appear to be due to optical depth efects. Peliminary analysis is presented to derive the physical conditions of the emitting gas.
The Large Magellanic Cloud R CrB Star - HV 12842
Authors: Morgan D.H. , Nandy K. , Rao N. Kameswara
Published: July 2016

The star HV12842 is one of the 5 R CrB stars listed in the catalogue of variable stars in the LMC (Payne-Goposchkin 1971) and is located 4 deg. to the north of 30 Doradus. At this location it falls in the north-eastern part of one of two standard LMC fields used by the UK 1.2 m Schmidt Telescope. Since 1976 a series of I-plates (normally 90 minute exposures of hypersensitized Kodak IV-N emulsion through a Schott RG 715 filter) has been obtained on both the standard fields (LMC (N) and LMC (S)). This paper describes the behaviour of HV 12842 during the period 1976-1985 as it appears on the 38-I-plates of LMC(N) taken with the UK 1.2 m Schmidt Telescope. Earlier, the UBV magnitude at maximum light are given as V=13.65, B−V=0.51, U−B=−0.11 (Sherwood 1974) and the spectral type as F (Feast 1979).
Spectral Variations of the Rapidly Oscillating Ap Star HD 60435
Authors: Matthews J.M. , Slawson R.W. , Wehlau W.H.
Published: July 2016

The peculiar F star HD 60435 exhibits broadband light oscillations of low amplitude with periods between 15 and 4 minutes. Photographic spectra obtained in January/February 1985 using the University of Toronto 0.6 m telescope on Las Campanas, Chile, reveal that the star also undergoes slow spectral variations like those observed in many Ap stars. The data further suggest that Sr II maximum may coincide with maximum amplitude of light oscillations. According to the oblique pulsator model (Kurtz 1982) for such variables, this implies that Sr II is concentrated near at least one of the magnetic poles of HD 60435.
Hydrogen Deficient Planetary Nebulae: Preliminary Results
Authors: Pottasch S.R. , Mampaso A. , Manchado A. , Menzies J.
Published: July 2016

New spectra of A78 and A58 at different positions in the nebulae are presented. An abundance gradient is found in A78, extending quite close to the center. Similarly the nebulous knot near the center of A58 has considerably higher heavy element abundances than the outer regions of this nebula. The ionization state is considerably lower in A58 than A78. In A78 most of the neon is in the form of Ne+3 and Ne+4, indicating that the standard ionization correction factor as used by Jacoby and Ford, is substantially in error. Finally, the very high infrared excesses found in this nebulae are discussed.
A Determination of Magnetic Fields of T Tau and Ae/Be Herbig Stars Using the Parameters of Their Linear Polarization
Authors: Gnedin Yu.N. , Pogodin M.A. , Red’kina N.P.
Published: July 2016

Attempts of applying stellar polarization spectra to evaluation of magnetic fields of some types of stars are described.
The Distribution of Fe, Cr and Si Over the Surface of Θ AUR
Authors: Khokhlova V.L. , Rice J.B. , Wehlau W.H.
Published: July 2016

Very accurate spectroscopic line profiles have been obtained at various phases during the 3d.618 period of the magnetic variable Ap-star Θ Aur. These profiles were observed using a Reticon detector at the coudé focus of the 3.5 metre Canada-France-Hawaii telescope. The mapping of Si, Cr and Fe over the surface of the star was done by solving the Inverse Problem. Complex spotty structure has been revealed with the number of Fe spots found being as great as six. The distribution of Cr is found to be similar to Fe but with less detailed structure. Si is distributed quite differently from Fe and Cr. Discussion of the relationship of the magnetic field maximum phase and the light curve along with the maps of the distribution of elements suggests that the principal spots of Fe and Cr are in phase with the light variability but they are 90° out of phase with Si and the magnetic field variation. We are surprised by the Si variability seeming to be 90° out of phase with the light variability.
The Analysis of Chemical Composition of Am Star Atmospheres
Authors: Boyarchuk A.A. , Savanov I.S.
Published: July 2016

The Survey of principal physical characteristics of the atmospheres of Am stars has been carried out. The anomalies of chemical composition have been discussed. The deficiency in C, O, Mg, Ca, and Sc alongside the excesses of heavier-than-Ni elements, with respect to Fe has been pointed out. The hypothesis on the nature of the observed anomalies are briefly discussed.
Investigating Astronomy’s History
Authors: Sperling Norman
Published: July 2016

Amateur astronomers play an important role in historical astronomy and publish a wide range of studies. They can participate nearly as well as professional astronomers since neither are professional historians or archaeologists. Amateurs often restore old instruments and facilities, discovering clues to their design, manufacture and use that would not be noticed by non-astronomical historians.

Possible studies include histories of institutions and of astronomy in different countries, biographies, and evolution of ideas. Publications and manuscripts could be studied for matters of current and historical importance. Folklore (of all countries) should be recorded before it dies out, and the beliefs behind it examined. More study groups involving amateurs, professionals and others should be established.
An Amateur CCD Camera
Authors: Buil Christian , Prat Guylaine , Thouvenot Eric
Published: July 2016

A CCD camera was built in 1984 using a linear detector (Thomson TH7810A) with 1728 pixels. The simplicity of this sort of detector enabled us to gain experience with CCDs. With a linear detector it is possible to carry out spectroscopy or even two-dimensional imaging by shifting the observed field at right angles to the photosensitive strip and by acquiring data in a regular manner (the scanning technique). The limitations of this equipment soon became apparent when trying to image deep-sky objects, so a second camera was built in 1985 using a CCD array, a Thomson TH7851 with 208 × 144 pixels. Numerous improvements were later made and the most advanced model is described.
Searching for Comets
Authors: Mayer Ben
Published: July 2016

Methods of searching for comets, novae and other events using projection and video blink methods, and simple orientation aids were described. The methods are covered in the following references:

1.

Liller, W., Mayer, B.: The Cambridge Astronomy Guide, Cambridge University Press, 1985

2.

Mayer, B.: International Halley Seminar, Alden Biessen, Belgium, 1986 Oct.25

3.

Mayer, B.: 20th ESLAB Symposium, “Exploration of Halley’s Comet”, Heidelberg, 1986 Oct.27-31

4.

Mayer, B.: Mercury, (Journal of the Astronomical Society of the Pacific), 1987 July/August
Trying to Reduce Errors in Visual Estimates of Variable Star Magnitudes
Authors: Velasco E. , Velasco P.
Published: July 2016

The light-curves of many variables, prepared from a large number of individual estimates by many different observers, have a lot of scatter, ranges greater than one magnitude being common, although it is generally accepted that the eye can detect differences of roughly 0.1 magnitude, at least for stars of moderate brightness. The question arises whether these gross discrepancies can be reduced. We think that this is possible if observers make better use of their observational capabilities.

For certain types of variable stars, e.g. long-period ones, the lack of accuracy may often be balanced by the vast number of estimates available. But for other stars, especially those exhibiting small-amplitude fluctuations, this process of combining observations leads to broad light curves that completely hide any possible fluctuations. Variable-star observers are familiar with these problems, but it is desirable to try to improve the accuracy that can be obtained.
Wanted: An International Jovian-Satellite-Phenomenon Centre
Authors: Wieth-Knudsen Niels P.
Published: July 2016

Amateur observations made since 1977 show that although the ephemerides for the satellites of Jupiter published by the Jet Propulsion Laboratory are more accurate than those in the Astronomical Almanac, there are still small deviations, which may increase with time. Observation of eclipses, transits and occultations, as well as of the mutual phenomena that occur at 6-yearly intervals can provide information for correction of the ephemerides. There appear to be three groups coordinating observations: 1) in Germany, started by P. Ahnert in the early 1960s and now under H.-J. Blasberg; 2) in the U.S.A., started by J. Ashbrook in 1976, and continued by J. Westfall of the ALPO; 3) in Australia and New Zealand, led by B. Loader. These groups appear to work independently, and it would greatly help research on this subject if there were an International Centre for collecting observations of the Jovian satellites – perhaps under the supervision of the IAU – whereby all observations made anywhere in the world would be available to anyone investigating the subject. Paris, where the predictions are calculated, might be a very suitable site for such a centre.
Feeding the Five Thousand
Authors: Enock Muriel
Published: July 2016

The Dominion Astrophysical arranged 20 special viewing sessions for Comet Halley, and although most of these were clouded out, some 3000 people attended. The Observatory receives 30 000 visitors annually and its display area was recently renewed. This was done on a very limited budget, but the display succeeded in providing both scale and distance models of Solar-System bodies, telescope models, and much visual material, all accompanied by bi-lingual text.
Surface Distribution of M Stars With Different IRAS Colour
Authors: Ishida Keiichi , Othman Mazlan
Published: July 2016

The surface distribution of M stars is studied by differentiating them according to whether they show a circumstellar dust shell (CS) or not. Analysis shows that galactic latitudinal and longitudinal distributions are not determined by spectral subclasses alone. The study also indicates that the M type stars with CS have higher intrinsic luminosities in the K band than those without CS. The M stars used in the study are obtained from the Two Micron Sky Survey catalogue (IRC) which is an unbiased sample with respect to the interstellar extinction. The CS feature is identified by the ratio of flux densities at 12 and 25 μm in the IRAS point source catalog.
Excitation of Non-Radial Oscillations by Overstable Convection in Differentially Rotating Massive Main Sequence Stars
Authors: Lee Umin
Published: July 2016

We investigated overstable convective modes of differentially rotating massive main sequence stars. It is examined that the overstable convective modes in a rapidly rotating convective core may excite envelope non-radial oscillations by the resonance coupling between them. Let us denote by q the ratio of the angular velocity of the rapidly rotating core to that of the envelope. Then, it is found that as the ratio q increases, the order of the non-radial g modes resonantly coupled with the convective mode becomes lower, so that the excited g modes come to have shorter periods in an inertial frame. It is also found that when the separation of the frequencies of the consecutive envelope g modes is wider than the resonance width, there occurs the alternation between the strong and the weak resonances, i.e., the resonantly coupled mode becomes overstable or neutral according to the strength of the resonance.
New Observational Results of Of/WN - Transition Types
Authors: Wolf B.
Published: July 2016

Of/WN stars have been introduced by walborn (1977). These luminous stars are particularly characterized by the appearance of both the characteristic of emission lines of HeII and NIII and strong HeI and [NII] emissions. These objects have become particularly interesting due to the discovery of their link to the S Dor variables (Stahl et al. 1983, Stahl 1986, Wolf 1987). They are supposed to represent key objects in the evolution of massive stars being the immediate progenitors of WN stars. We observed the Of/WN transition type stars R127, R84, and S61 of the LMC with high dispersion spectroscopy in the optical and satellite-UV range. R127 is at present undergoing an S Dor-type outburst. In 1986 R127 became the visually brightest star of the LMC until it was surpassed by SN1987A in Feb. 1987. The spectrum in the optical range during the extraordinary bright outburst phase is distinguished by numerous P Cygni type lines of singly ionized metals. Since the beginning of the present outburst the spectral type has gradually become later and the equivalent spectral type as derived from our latest CASPE spectrum taken in 1986, August 22 was middle A. The IUE-spectrum of R127 during maximum is characterized by copious lines of singly ionized metals formed in the wind. A detailed disucssion of the optical and satellite UV high dispersion spectrograms of R127 taken during its present extraordinary bright outburst phase is forthcoming in Astronomy and Astrophysics (Wolf et al. 1987a).
A Sensitive Line Search in Circumstellar Envelopes
Authors: Nguyen-Q-Rieu  , Deguchi S. , Izumiura H. , Kaifu N. , Ohishi M. , Suzuki H. , Ukita N.
Published: July 2016

A molecular line search in the range between 85 and 89 GHz has been performed in the circumstellar envelopes of 11 evolved stars. Emissions of 29SiO J=2−1,28SiO J=2−1, HCN J=1−0, H13CN J=1−0, HC5 N J=33−32, HCO+ J=1−0 transitions and other transitions of C2 H, C4 H, and C3 N have been observed in 11 stars. We have detected the ground state 29SiO J=2−1 maser in several stars. We have also detected HCN emission in VY CMa. A narrow H13CN spike feature near the central velocity has been found in the spectrum of CRL 2688.
The

V

-Stokes Parameter as a Manifestation of Envelope Activity for Cool, Bright, Evolved Stars
Authors: Holenstein B. D. , Koch R. H. , Pfeiffer R. J.
Published: July 2016

At Pennsylvania’s Flower and Cook Observatory, instrumentation has been developed to measure simultaneously the four Stokes parameters of the filtered radiation field from a celestial source. The instrumental Q/U/V-parameters have been found to be very small and well-behaved. Thus far, the program has concentrated on cool bright giants and supergiants and on hot, evolving close binaries. A single season’s investigation of Alp Ori has already been reported (Holenstein 1987) and the present paper is a summary of current results for the cool, evolved program stars.

For Psi1 Aur, V CVn, 6 Gem, 72 Leo and 119 Tau no V-signal at the level of 3σhas been detected from data from the 1986-1987 season. At the level of 0.0n%, unambiguous and variable V-signals have been detected for VV Cep, Mu Cep, Alp Her, Alp Ori, Bet Peg, and Alp Sco.
The Structure of a Stationary Atmosphere with a Heat Source or Sink
Authors: Nariai Kyoji
Published: July 2016

There are several methods for solving a structure of a stellar atmosphere in radiative equilibrium. Among them, the matrix method (Nariai and Shigeyama 1984, Nariai and Ito 1985) uses only the energy equation at the nodes; therefore, it is easy to extend this method to an atmosphere that is not in radiative equilibrium. The matrix method gives direct solutions for the cases of a gray model or a picket–fence model, and it is so effective that the calculation converges in 3 or 4 iterations in the case of a non-gray atmosphere with scattering even if the starting model is isothermal. In order to simplify the problem, in this paper, however, we will limit ourselves to the case of a gray atmosphere with pure absorption.
Supernova Mechanisms: Before and After SN1987a
Authors: Kahana Sidney H.
Published: July 2016

The impact of SN1987a on theoretical studies of the specific mechanism generating Type II supernovae is examined. The explosion energy extracted from analysis of the light curve for SN1987a is on the edge of distinguishing between a prompt explosion from a hydrodynamic shock and a delayed, neutrino-induced, explosion. The detection of neutrinos from 1987a is also reanalysed.
Chemical Composition of High-Energy Cosmic-Ray Nuclei and its Possible Origin in Type-II Supernova
Authors: Takahashi Yoshiyuki
Published: July 2016

High energy cosmic ray spectrum has been known to have an interesting bump in the energy range 1014 − 1016 eV. Various models to explain the spectral break in this energy range have been so far proposed; which incorporate either a large-scale termination of galactic wind, shocks with greater age and spatial extent associated with hypothetical super-bubbles powered by multiple supernovae, intersection of two quantum-gravitational components, extra-galactic component, red-shift of big-bang remnant, or a proton component from pulsars. More recently, their possible origin in type-II supernovae with magnetic acceleration mechanism is proposed by considering direct observational results of chemical composition near the bump regime of cosmic ray spectrum.
Concluding Remarks – II
Authors: Sugimoto D.
Published: July 2016

In the Opening Remarks Dr. Kudritzki asked what tricks were used in calculating stellar structure. Though many fine models and discussions have been presented, answer has not been given yet to this question. The theory of stellar structure consists of two very much different kinds of building blocks. One is the local physics such as equation of state, opacity, nuclear reaction rate, and so on. They are determined only locally when the values of temperature and density at a point are given, i.e., they are irrelevant to the conditions whether they are considered in the stellar interior or not. Another is the physics of self-gravitating systems in which the global spatial structures are discussed. Characteristics of astrophysics are often said to lie in the fact that it covers much wider parameter ranges than in laboratories. This, however, grasps only one side of the problem, i.e., only local physics. Those which are not encountered in laboratory physics lie mainly in the global physics. It shows characteristics out of common sense; examples are negative specific heat and associated gravothermal catastrophe which are related with the gravitational contraction of the stars, formation of core halo structures which is observed not only in red giant stars but also many celestial objects, and tendencies dividing a system into two sub-systems one with high energy and/or high entropy and the other with low energy in the deep potential well and/or low entropy as seen in supernova explosion of type II and formation of jet in various objects. They behave contrary to the general trend, i.e., against equipartition and thermal equilibration.
The initial/final mass relation for stellar evolution with mass loss
Authors: Weidemann Volker
Published: July 2016

The relation between initial and final masses is discussed under consideration of changing theoretical concepts and new empirical data on masses of white dwarfs and nuclei of planetary nebulae. It is concluded that presently adopted schemes of evolution need revision, and that no universal relation exists.

The strongest evidence for large amounts of mass loss during stellar evolution has been provided by the existence of white dwarfs – with masses typically of 0.6 m (m = M/Mʘ), much below the galactic turn-off masses – and by the phenomenon of planetary nebula production before a star descends into the white dwarf region.
Effects of mass loss on the formation of planetary nebulae
Authors: Kwok Sun
Published: July 2016

The idea that planetary nebulae (PN) originated from outer layers of red giants goes back to Shlovskii (1956). This hypothesis was supported by Abell and Goldreich (1966) who argued convincingly that red giants are the most likely progenitors of PN. Although this is generally accepted today, the details of the transition from red giants to PN remain in controversy. It was pointed out by Paczyński (1971 a) that PN progenitors must have similar luminosities to central stars of PN, and therefore are likely to be late-type supergiants undergoing double-shell burning. The advent of infrared astronomy led to the discovery that most, if not all, late-type giants and supergiants are losing mass at rates of 10-6 - 10-5 Mʘyr-1 (Gehrz and Woolf 1971). Such mass loss rates greatly exceed the nuclear burning rate (6 x 10-8 - 5 x 10-7 Mʘyr-1 for stars with core masses between 0.6 and 1.2 Mʘ) and must be the dominant factor in the late evolution of intermediate mass stars. The observation of white dwarfs in open clusters implies that up to 6 Mʘ can be lost during the red-giant phase (Romanishin and Angel 1980). Since the observed masses of PN are no more than a few tenths of a solar mass, the existence of massive circumstellar envelopes formed by steady mass loss must have an effect on the formation of PN.
Manifestation of the 160-min Solar Oscillations in Velocity and Brightness (Optical and Radio Observations)
Authors: Kotov V.A. , Severny A.B. , Tsap T.T. , Moiseev I.G. , Efanov V.A. , Nesterov N.S.
Published: July 2016

All evidence of the solar origin of 160-min period oscillations is collected, and the present state of observations of this oscillation in optical and radio-ranges is considered. The main results are summarized: (a) the 160-min oscillation was observed in 1981 as well as before, (b) an attempt to find a nonradial component with l = 2 has failed, (c) the intensity and circular polarization of radioemission show with statistical significance the presence of this 160-min periodicity.
Detection of Individual Normal Modes of Oscillation of the Sun in the Period Range from 2 Hr to 10 Min in Solar Diameter Studies
Authors: Bos Randall J. , Hill Henry A.
Published: July 2016

New observations of solar oscillations are reported. Power density spectra derived from these observations reveal narrow-band oscillations that are spatially global, have spatial symmetry properties that are either symmetric or antisymmetric for reflection about the center of the solar disk and also about the solar equator, and have coherence times ≿41 days. Large-scale differential refraction effects have been reduced by a factor of 105 over that found in previous solar diameter studies by the design of the experiment; thus, these effects are eliminated as a possible source of the oscillations. A discussion is presented of this reduction as well as other features of the observing and analysis program. It is concluded that the probability is very high that individual normal modes of oscillation of the Sun have been detected in the period range from 2 hr to 10 min.
On the Origin of Oscillations in a Solar Diameter Observed through the Earth's Atmosphere: A Terrestrial Atmospheric or a Solar Phenomenon
Authors: Hill Henry A. , Bos Randall J. , Caudell Thomas P.
Published: July 2016

Interpretations of current and past results from ground-based solar diameter measurements, as well as the planning of scientific programs for the 1980’s, are strongly dependent on the perceived level of the degrading effects of the Earth’s atmosphere. One of the more effective approaches has been to design the observing program and the subsequent data analysis such that the solar diameter measurements themselves could provide an evaluation of atmospheric effects. Many important results have been obtained in studies of this type and these results are collected here to help in appraising the current situation. This evidence all points in one direction: the Earth’s atmosphere, while complicating the design of observational programs, is not the source of the oscillations observed in solar diameter measurements. Further, this same evidence indicates that the Earth’s atmosphere will not pose any serious limitations in ground-based solar diameter studies during the 1980’s.
Evidence for the Phi-Dependent Rotation-Oscillation of the Sun (and for the Driving Mechanism of the Asymmetric Dynamo)
Authors: Csada I.K.
Published: July 2016

Longitude-dependent oscillations of the solar rotation are derived from the 27-day averages of the photospheric velocity data. Two pairs of prominent periods are obtained. Their harmonic means correspond to a semiannual variation and to the first harmonic of the latter. To explain the origin of the oscillation the corona and the interplanetary material are supposed to rotate parallel to the planetary plane with an inclination to the solar equator. The non-uniform shearing around the equator is assumed to result in oscillation with a period of half of a year.
Atmospheric Internal Gravity Waves as a Source of Quasiperiodic Variations of the Cosmic Ray Secondary Component and their Likely Solar Origin
Authors: Galper A.M. , Kirillov-Ugryumov V.G. , Leikov N.G. , Luchkov B.I.
Published: July 2016

Hard gamma-radiation fluctuations with the periods from 4 to 60 min were investigated in the
course of balloon flights at altitudes of 30–40 km. Quasiperiodic intensity variations (QPV) were observed with periods of 5 min, 12–15 min, and 23–26 min, those of 5 min predominating. QPV last no longer than several hours, their associated amplitudes ranging from 5 to 20%. QPV were observed both in mid-latitudes and in the tropics, their detection probability for 3h exposure being 0.3. In the total charged component QPV with comparable amplitudes were not registered. Synchronous atmospheric pressure variations were recorded practically with an amplitude 20 times less than that of gamma-radiation. This suggest short internal gravity waves (IGW) in the stratosphere in the range from 10 to 100 km as the most likable source of QPV. Since the temperature profile of the Earth atmosphere provides conditions for superdistant waveguiding propagation of short IGW with a period of ∼ 5 min at altitudes of 110 and 30 km, the source of waves can be well away from the point of their registration. The IGW generation in the stratosphere can be attributed to the resonance caused by global solar oscillations with low l modes. The resonance probability is likely to be due to the hard solar radiation variations which are absorbed in the ozone layer. The coincidence of the frequency oscillation range in the chromosphere and that of IGW in the stratosphere suggests an IGW resonant excitation mechanism in the Sun–Earth system.
The ITA Survey on Red Dwarf Variable Stars – Final Report
Authors: Torres C.A.O. , Busko I.C. , Quast G.R.
Published: July 2016

From 1971 to 1973, an observational survey on red dwarf stars to search for possible periodic photometric variations was carried out at ITA Observatory - Brazil. Two observing runs at Cerro Tololo in 1974 and 1975 were used as an extension of this survey. We observed a total of 90 stars, as shown in Table I, and almost all stars were measured at least five times during the same season.
EV Lacertae: Is Flare Activity Related to an Unseen Planet-Like Companion?
Authors: Lippincott Sarah Lee
Published: July 2016

The presence of an unseen companion to EV Lac with 2 to 4 Jupiter masses is likely. A period of ~45 years indicates the separation at the time of periastron is ~2 a.u.
OPTICAL AND ULTRAVIOLET STELLAR FLARE SPECTROSCOPY
Authors: Worden Simon P.
Published: July 2016

As for solar flares, one of the most physically revealing types of data for M-dwarf flares are high-resolution, time-resolved spectra. Due to the intrinsically faint nature of the M-dwarf stars, spectroscopic data has tended to be of low spectral (˜ 5 Ǻ) and temporal (˜ 5 min) resolution. However, with the development of image intensified spectrographs and fast, efficient digital detectors, the last several years have seen the successful acquisition of both high time and spectral resolution M-dwarf flare spectra. Recent programs have also been successfully conducted using the International Ultraviolet Explorer (IUE) satellite to obtain UV and EUV spectra of M-dwarf flares. These data reveal that dwarf M star flares are remarkably similar to solar flares in all aspects of their spectroscopic phenomenology.