bluuebunny/crossref_metadata_2025 huggingface dataset:
Activities of Astro-Geodynamics Research in China
Authors: Ye Shu-hua
Published: July 2016

In recent years, efforts of Astro-Geodynamics research in China have mainly been concerned with the exploration of the regularity and mechanism of the rotational and crustal motion of the Earth as well as with the possible relationships between astronomical factors and earthquakes. In the meantime, our observational devices are under modification and some new techniques have been established.
Results from Lunar Laser Ranging Data Analysis
Authors: Dickey J. O. , Williams J. G. , Yoder C. F.
Published: July 2016

The lunar laser range data taken at McDonald Observatory between August 1969 and May 1980 has been analyzed. The simple rms residual for the 2954 ranges is 31 cm. Results of the analysis include GMearth = 398600.45±0.02 km3/sec2 and a secular acceleration of the lunar orbital mean longitude of ṅ = −23.8±1.5“/century2 which yields a Q of 12.3 at semidiurnal frequencies. The lunar harmonic C30 is (−8.7 ± 1.1) × 10−6 and the lunar rotational dissipation k2mT = (4.7 ± 0.5) × 10−3 day. Also resulting from the solution are geocentric coordinates of McDonald accurate to 30 cm, including the first value for the longitude with the new IAU constants and a dynamical equinox.
Comparison of Lunar Ephemerides (Sale and ELP) with Numerical Integration
Authors: Kinoshita Hiroshi
Published: July 2016

SALE and ELP, analytical theories of the main problem of the Moon, are developed by Henrard (1979) and Chapront-Touzé (1980), respectively. Both theories are compared with numerical integration over one year, which covers about 13 revolutions of the Moon’s orbit. The root-mean-square residuals in the distance of SALE truncated at 10−5 arcsecond is about 10 cm for series truncated at 10−5 arcsecond and 1.2 cm for series truncated at 10−6 arcsecond. ELP is also compared with 20 years of numerical integration and the root-mean-square residuals in the distance is about 1.5 cm.
On the Accuracy of the 1980 IAU Nutation Series
Authors: Yatskiv Ya. S. , Molodensky S. M.
Published: July 2016

At the Seventeenth IAU General Assembly in Montreal, Canada, in 1979, the resolution was passed adopting the 1979 Nutation Series, which was based on: - the development of the rigid theory by Kinoshita (1977); - the modifications to this theory allowing for the effects of a fluid core and an elastic shell (Molodensky, 1961). The purpose of this action has been nothing but the adoption of a working Standard on Nutation. The details that follow are well known (Seidelmann, 1980). After a discussion at IAU Colloquium N°56 in Warsaw, Poland, in 1980, the Working Group on Nutation decided to recommend a change to the 1980 IAU Nutation Series, which is based on the theory developed by Wahr (1980). The differences between the above mentioned Series are within the limits of ±0002 and are not detectable with the present observational accuracy. As an example, we summarized in Table 1 the observed amplitudes of circular nutation component (2L☾−α) which were determined from astronomical observations with best accuracy. The effect of O1-tide on this component is taken into account by using the theoretical tide with Λ=1+k−1=1.2. The theoretical amplitudes of this component were reduced to the mean epochs of observations.
The European Space Information System - ESIS
Authors: Albrecht M. , Bodini A. , Russo G.
Published: July 2016

The general users requirements for the ESIS project are presented.
Correspondence, Unpublished Papers and Data: Present making of Historical Records
Authors: Motais de Narbonne Anne-Marie
Published: July 2016

Research process generates public and formal informations accessible through published documents or public data bases which libraries are used to deal with. It also generates informal, anachieved informations in format of correspondances, notes, calculus, reports, drawings... or other unpublished documents that libraries must not either leave aside.

Since fundamental research, versus technological research for instance, implies great personal involvement, informal informations are mainly issued from individuals or small groups of individuals. It is probably the reason why this kind of informations and documents is often considered erronously as private by astronomers deciding by themselves to destroy, to move or leave behind their so-called personal papers. These documents and informations actually belong to the institutions. They must be preserved because they are part of the research production and also because they may be used for astronomical research as it is illustrated in S. Débarbat’s communication.
The Astronomical Library of the Future
Authors: Molholt Pat
Published: July 2016

Daniel Bell, of Harvard, has said that “The world society is like a set of giant Calder mobiles, shifting in uneasy balance in accordance with the winds of change, but the exact configurations are difficult to capture - especially for twenty-five years from now.” Twenty-five or thirty-five, the number is not important - any look into the future is difficult and risky. In order to get a sense of what the future of astronomy libraries may be, I want to talk about some of the changes that are beginning to take shape and then look at the effect those changes are likely to have on all libraries including those that concern us today — astronomy libraries.
Outdoor Lighting in Tucson: A Photo Record
Authors: Robinson William T.
Published: July 2016

Photographic documentation of outdoor lighting installations has been underway in Tucson and throughout Arizona for some time. Such photos show what can be done to minimize the problem of light pollution, illustrating examples of both good and bad lighting designs and installations. Copies of such photos (mostly in the form of slides) are available from the International Dark-Sky Association.
Light Pollution at the Astronomical Observatories in Mexico
Authors: Costero R.
Published: July 2016

There are three astronomical observatories in Mexico working on research programs. The oldest one is located at Tonantzintla, Puebla; the largest is at San Pedro Martir, Baja California; and the youngest, not yet in full operation, at Cananea, Sonora. The one at Tonantzintla suffers, by far, the largest light pollution problems; that at San Pedro Martir has the darkest skies but is relatively close to regions of potential touristic and mining developments. In this paper we summarize the existing and potential polluting problems arising from manmade light sources near those observatories, and suggest some possible steps to be taken in order to minimize their adverse effects on astronomical observations.
The Disappearance of Darkness
Authors: Sperling Norman
Published: July 2016

Until the last century, virtually all humans knew the appearance of the dark night sky. Even unschooled urbanites knew some constellations and planets. By 1909, light pollution made authors admonish readers to do their skywatching from the countryside rather than the city. The warnings have escalated along with the light pollution. Light pollution’s effect on professional and volunteer observational astronomy, along with telescopes’ changing focal ratios, largely determine which kinds of astronomy are done in which institutions. In times and places where individuals perceive little possibility to change their culture, astronomers cope as best they can. When activism earns results in other cultural matters, astronomers sometimes become activists to fight light pollution. Chabot Observatory has felt many of these influences in its 105-year history, and they can be read in its plans for the future as well. Despite winning some battles, the war against light pollution is still being lost, so a different approach is suggested.
I.U.C.A.F and Frequencies for Radio Astronomy
Authors: Findlay John W.
Published: July 2016

Many papers in the Colloquium describe the difficulties which now exist when radio astronomers try to make highly sensitive observations in various regions of the spectrum. The author has been involved for about 30 years in attempts to get parts of the radio spectrum “protected” so that radio observations could be made in these regions free from damaging interference. Thus it may be interesting in this paper to look backward to the work done by many people before and during the International Telecommunications Union (ITU) World Administrative Radio Conference (WARC) of 1959, and to describe briefly the outcome of that WARC.
Coordination Between the Radioastronomy Service and the Radiodetermination Satellite Service in the 1612 MHZ Band
Authors: Thompson A. R.
Published: July 2016

The Radiodetermination Satellite Service (RDSS) provides radiolocation and limited communication for users of aeronautical, marine and terrestrial vehicles. A system of the RDSS is being developed in the United States by the Geostar Corporation (Rothblatt, 1988). In this system signals from a control center are transmitted to transceivers on users’ vehicles through one of a series of two or three satellites spaced along the geostationary orbit, and responses are received through each of these satellites. If three satellites are used, locations of vehicles can be determined from the measured times of transmission from the control center to the user and back via different satellite paths. If two satellites are used the timing data must be supplemented by information such as altitude data from a terrain map, or an altimeter reading from the user’s vehicle, which can be encoded in the response transmitted back. Computation of the vehicle location is performed at the control center. The equipment at the vehicle can be relatively simple since its basic function is that of a transponder, and intervention by the vehicle operator is not necessarily required. However, provision can also be made for the inclusion of short coded messages from the vehicle, so the unit on the vehicle is usually referred to as a transceiver. The system is designed to meet the needs of various users; for example, trucking companies which must periodically monitor the locations of vehicles in a widely distributed fleet. Position information can be relayed to the company headquarters as well as to the vehicle operator. The role played by the central control computer in determining the locations requires that all vehicles using the service identify themselves by a transmitted code. Thus developers and operators of RDSS systems can lease their services to vehicle users.
Evolutionary diagnostics of LBV spectra and systems in the LMC
Authors: Walborn Nolan R.
Published: July 2016

The characteristics of the Ofpe/WN9 class in the LMC, including two newly discovered members, are reviewed; a strong relationship between this class and the LBVs is established by HDE 269858 = Radcliffe 127, currently in outburst with a spectrum identical to that of S Doradus. The evidence for CNO-cycle products,i.e., enhanced N and He, on the surfaces and in the circumstellar nebulae of Ofpe/WN9 objects and LBVs is discussed, with emphasis on recent near-IR observations of He/H. Finally, the occurrence of several Ofpe/WN9 and LBV stars in compact multiple systems will enable valuable information about the evolutionary status of the peculiar objects to be derived. Strong threads unite these three topics: the same objects frequently recur in each.
An ultraviolet view of the Luminous Blue Variables
Authors: Shore Steven N.
Published: July 2016

It is, perhaps, tautological to say that the luminous blue variables (LBVs), being luminous and blue, should be ideal targets for space ultraviolet observation. In fact, many have been observed on occasion and these will be discussed in this article. Mitigating circumstances, however, conspire to make this study difficult. The LBVs are rare and tend to be apparently faint, and since they are massive and formed in the plane in our Galaxy and in active star-forming regions in other galaxies, they tend to be heavily reddened. The stars were not really studied at all in the ultraviolet until the launch of theInternational Ultraviolet Explorer Satellite(IUE), with the notable exceptions of photometric observations of several of the galactic stars with ANS and TD-1 andCopernicusobservations of P Cygni (Hutchingset al. 1987).IUE, a small aperture (45 cm) spectrographic satellite, covering the spectral range from 1200 to 3300 A, allows for an adequate characterization of the UV properties of these stars.
Photometric variability of Luminous Blue Variables in quiescent state
Authors: Sterken C.
Published: July 2016

This paper reviews the major new facts on microvariability of LBV’s of the last few years, and discusses some observational requirements for the future.
Model atmospheres and quantitative spectroscopy of luminous blue stars
Authors: Kudritzki R.P. , Gabler A. , Gabler R. , Groth H.G. , Pauldrach A.W.A. , Puls J.
Published: July 2016

The basic physics of model atmospheres for Luminous Blue Stars (LBS) are discussed. The discussion comprises the model description of both subsonic photospheres and supersonic winds and the application of model calculations for the purpose of quantitative spectroscopy.
Atmospheric models for LBV’s at minimum and maximum states
Authors: Leitherer Claus , Schmutz Werner , Abbott David C. , Torres-Dodgen Ana V. , Hamann Wolf-Rainer , Wessolowski Ulf
Published: July 2016

We study the relation between photospheric and wind parameters of LBV’s on the basis of self-consistent atmospheric models. Our theoretical model consists of a spherically extended, dynamical NLTE atmosphere for the radiative transfer and a modified CAK code for the hydrodynamics. These codes are combined in an iterative scheme to achieve self-consistency.
A Homogeneous Sample of Binary Galaxies: Basic Observational Properties
Authors: Karachentsev I. D.
Published: July 2016

A survey of optical characteristics for 585 binary systems, satisfying a condition of apparent isolation on the sky, is presented. Influences of various selection effects distorting the average parameters of the sample are noted. The pair components display mutual similarity over all the global properties: luminosity, diameter, morphological type, mass-to-luminosity ratio, angular momentum etc., which is not due only to selection effects. The observed correlations must be caused by common origin of pair members. Some features (nuclear activity, color index) could acquire similarity during synchronous evolution of double galaxies.

Despite the observed isolation, the sample of double systems is seriously contaminated by accidental pairs, and also by members of groups and clusters. After removing false pairs estimates of orbital mass-to-luminosity ratio range from 0 to 30 f⊙, with the mean value (7.8 ± 0.7) f⊙. Binary galaxies possess nearly circular orbits with a typical eccentrity e = 0.25, probably resulting from evolutionary selection driven by component mergers under dynamical friction. The double-galaxy population with space abundance 0.12±0.02 and characteristic merger timescale 0.2 H−1 may significantly influence the rate of dynamical evolution of galaxies.
Blue Ellipticals in Compact Groups
Authors: Zepf Stephen E. , Whitmore Bradley C.
Published: July 2016

We examine the hypothesis that mergers of spiral galaxies make elliptical galaxies by studying galaxies in compact groups. We combine dynamical models of the merger-rich compact group environment with stellar evolution models and predict that roughly 15% of compact group ellipticals should be 0.15 mag bluer in B – R color than normal ellipticals. The published colors of these galaxies suggest the existence of this predicted blue population, but a normal distribution with large random errors can not be ruled out based on these data alone. However, we have new UBVRI data which confirm the blue color of the two ellipticals with blue B – R colors for which we have our own colors. This confirmation of a population of blue ellipticals indicates that interactions are occurring in compact groups, but a blue color in one index alone does not require that these ellipticals are recent products of the merger of two spirals. We demonstrate how optical spectroscopy in the blue may distinguish between a true spiral + spiral merger and the swallowing of a gas-rich system by an already formed elliptical. We also show that the sum of the luminosity of the galaxies in each group is consistent with the hypothesis that the final stage in the evolution of a compact group is an elliptical galaxy.
HI Observations of the Peculiar Galaxy NGC 660
Authors: Gottesman Stephen T. , Mahon Mary Elaine
Published: July 2016

We present observations of HI emission from the peculiar galaxy NGC 660. HI was detected in the companion galaxy UGC 01195 as well. Sixteen hours of observations were obtained with the VLA telescope of the National Radio Astronomy Observatory during December 1986 and March 1987.
The Morphology of Sérsic-Pastoriza Galaxies
Authors: Yates G.J. , Pedlar A. , Saikia D.J. , Unger S.W. , Axon D.J.
Published: July 2016

In this paper we present the preliminary results of our radio-continuum and neutral hydrogen observations of Sérsic-Pastoriza (S-P) galaxies. We show that the central regions contain a population of compact features thought to be young supernova remnants (SNRs) and discuss the overall morphology of the nuclei.
Are Extremely Luminous Far-Infrared Galaxies the Result of Merging Quasar Cores?
Authors: Norris R.P.
Published: July 2016

Extremely Luminous far-infrared galaxies (ELFs) are a class of galaxy discovered independently by several groups. The class is characterised by a quasar-like total luminosity (1011 — 1013 L⊙) which is radiated almost entirely in the far-infrared, and it has been suggested that obscured quasar cores may be responsible for generating this luminosity. Here I demonstrate that ELFs appear in several guises which can be characterised by the number of quasar cores they contain (zero, one or two), and develop a unified model to account for these differences.
Deep Fabry-Perot Imaging of NGC 6240: Kinematic Evidence for Merging Galaxies
Authors: Hawthorn J. Bland , Wilson A. S. , Tully R. B.
Published: July 2016

We have observed the superluminous, infrared galaxy NGC 6240 (z = 0.025) at Ha with the Hawaii Imaging Fabry-Perot Interferometer (HIFI – Bland and Tully 1989). During the past decade, observational evidence from all wavebands indicates that the unusual appearance of NGC 6240 has resulted from a collision between two gas-rich systems, a view which is supported by our spectrophotometnc data. However, the origin of the enormous infrared luminosity (4 × 1011 L0) detected by IRAS remains highly controversial, where opinions differ on the relative roles of large-scale shocks, massive star formation or a buried “active” nucleus. These mechanisms are discussed in the light of our Fabry-Perot observations.
On Leading Spiral Arms in Close Pairs of Galaxies
Authors: Fridman A. M.
Published: July 2016

It is explained why one can observe a leading spiral pattern in close pairs of galaxies where the direction of the orbital momentum of the satellite is opposite to the direction of the spin of the spiral galaxy.
What Determines The Bulge to Disk Ratio of Galaxies
Authors: Roos Nico
Published: July 2016

Galaxies having the same luminosity may have very different bulge to disk ratios, while the mean bulge to disk ratio slowly increases with total luminosity (Schechter and Dressier, 1987, Sandage et al., 1985). Such a behaviour is expected if ellipticals and the spheroidal components of disk galaxies are produced by secondary accretion of galaxies by larger galaxies. This is illustrated using a simple toy model of the evolution of the mass function of galaxies due to galaxy mergers.
Induced Starburst and Nuclear Activity: Faith, Facts and Theory
Authors: Shlosman Isaac
Published: July 2016

The problem of the origin of starburst and nuclear (nonstellar) activity in galaxies is reviewed. A physical understanding of mechanism(s) that induce both types of activity requires one to address the following issues: 1) what is the source of fuel that powers starbursts and active galactic nuclei? and 2) how it is channeled towards the central regions of host galaxies? As a possible clue, we examine the role of non-axisymmetric perturbations of galactic disks and analyze their potential triggers. Global gravitational instabilities in the gas on scales ~ 100 pc appear to be crucial for fueling the active galactic nuclei.
Precise Radial Velocities
Authors: Walker Gordon A.H.
Published: July 2016

Current techniques for the detection of long-term, low-amplitude (<50 m s−1), radial velocity variations are briefly reviewed together with some of their most successful programs. In the era of 8- to 10-m telescopes we must strive for a precision of < 1ms−1.
CORAVEL Surveys to Study Binaries of Different Masses and Ages
Authors: Mayor M. , Duquennoy A. , Halbwachs J.-L. , Mermilliod J.-C.
Published: July 2016

Preliminary results are given for a systematic survey of K-dwarf stars in the solar vicinity. Nine companions to the G and K dwarfs have very low M2 sin i, less than 0.08 M⊙. These detections from a sample of 540 G and K primary stars support the reality of the existence of companions with mass below 0.08 M⊙: brown dwarfs exist.

A comparison of the relative mass function distribution f(m)/M1 between low-mass (M1 < 1.3 M⊙) and intermediate-mass (2 < M1 < 5 M⊙) binaries suggests a dependence of the mass-ratio distribution on the mass of the primary: f(q, M1).

By combining the photometric information with orbital elements constraints, we have derived the mass-ratio distribution for intermediate-mass stars. As is the case for low-mass stars, this distribution does not have any maximum close to M2/M1 = 1.
Binaries in the Hyades
Authors: Stefanik Robert P. , Latham David W.
Published: July 2016

Orbital solutions are now available for 46 binaries which are members of the Hyades. The distribution of eccentricity versus period shows evidence for tidal circularization of the short-period binaries. However, the transition from circular to eccentric orbits is not clean. The first eccentric orbit has a period of 5.75 days, while the last circular orbit has a period of 8.50 days. For longer periods the distribution of eccentricity is the same as for solar-type stars in the field.
Method for the Calculation of Orbits of Spectroscopic-Interferometric Binaries with Mixed Data
Authors: Lanchares V.
Published: July 2016

From an initial value of the period and a fitted curve for the radial velocities an homotetic plane to that of the relative orbit is constructed from which i, Ω and parallax are deduced. The remaining orbital elements are obtained from the relations of the elliptical motion.
A Catalogue of Nearby Wide Binary and Multiple Stars
Authors: Poveda A. , Herrera M.A. , Allen C. , Cordero G. , Lavalley C.
Published: July 2016

No modern catalogue of wide binary and multiple systems (WBMS) exists for the region of the solar vicinity (stars nearer than ~22 pc), that include updated information on their membership to moving clusters and an age classification. With the aim of filling this gap, and also because of its importance for investigating the dynamical evolution of double and multiple systems, we have compiled a WBMS list extracted from the catalogues of nearby stars of Gliese (1969, also Gliese & Jahreiss 1979), as well as Luyten’s NLTT (Luyten 1979–1980, Luyten & Hughes 1980, see also Warren et al. 1989), the Bright Star Catalogue (Hoffleit 1982), the catalogue of Woolley et al. (1970) and other sources.

By comparing the transverse velocities of WBM systems with those expected for members of the Hyades and Sirius Superclusters, membership of some WBMS to them has been established. We have classified as probably young systems (PYS) those with one component satisfying at least one of various criteria of youth. A system that is not a PYS is classified as probably old (POS).

The catalogue contains 385 binaries and 85 systems of higher multiplicity. Out of these, 129 binaries are PYS and 256 are POS, while 32 multiples are PYS and 53 are POS.
Double Star Astrometry with the Carlsberg Automatic Meridian Circle
Authors: Argyle Robert W.
Published: July 2016

The Carlsberg Automatic Meridian Circle (CAMC) has been operating on the island of La Palma since 1984. Since that time it has made more than 500,000 observations of stars and minor planets. Observation are made by accumulating the output from a series of scans by a pair of 4″ wide slits which oscillate back and forwards across the star as it traverses the meridian (Helmer et al. 1991). The error of a single determination of a star position is 0″.14 in RA and Dec and 0.05 in V magnitude. For 20 observations, the errors of a mean position are reduced to about 0″.05.
Astrometry and Photometry of Trapezium–Type Multiple Stars
Authors: Bernacca P.L. , Lattanzi M.G. , Massone G.
Published: July 2016

Trapezia systems are defined as multiple stars, having three or more components with separation ratios in the range 0.3 to 3. The revival of interest in Trapezia is due to their potential astrophysical significance, as they could originate from a single protostar and be in an expansion stage because of their possible positive energy (see, for example, Bernacca 1988 and references therein). Further decisive advancements in understanding the nature of these systems require data for establishing a list of physically bound systems as well as for the systematic study of their kinematics and energetics. In the present progress report we test three representative cases with the combined exploitation of astrometric, photometric, and spectroscopic data.
Statistics of Double and Multiple Stars in the Solar Neighborhood
Authors: Orlov Victor V. , Titov Oleg A.
Published: July 2016

We study the multiplicity function and physical properties of single, double, and multiple stellar systems in the solar neighbourhood (r < 10 pc), using a new preliminary machine–readable version of the Gliese & Jahreiss Catalogue (1991).

The ratio of (n+l)-ple to n-ple systems is a constant fraction of about 1/4 for n =1, 2, 3, 4. The luminosity function f(M) for primaries in binaries has an additional peak at M є (6m,8m) that is absent in f(M) for single stars and secondary components. A significant correlation between the absolute magnitudes M1 and M2 of the components in binaries takes place.
Detection and Measurement of Double Stars with HIPPARCOS: Provisional Results from NDAC
Authors: Söderhjelm S. , Lindegren L. , Van Leeuwen F. , Evans D.W.
Published: July 2016

The HIPPARCOS satellite observes 118,000 stars from a predefined list. Some 10% of these are known doubles or multiples, and another 2—3% may ultimately be found to be non-single with separations above 0″.l and magnitude–differences below 4–5. This paper describes briefly the special reduction methods used by NDAC (Northern Data Analysis Consortium) for treating these non-singles. A key feature is the use of the main reduction results to calibrate and collect the data for individual doubles in ‘case history files’. This enables a global solution of both absolute and relative parameters for a double to be carried out in a single step. Using provisional data tapes covering small parts of a 14-month interval, tests have been made of major parts of the double star reductions. These early results are compared with independent HIPPARCOS data and with ground–based speckle interferometry.
How Double Star Astronomy May Develop After HIPPARCOS
Authors: Dommanget J. , Lampens P.
Published: July 2016

Now that the HIPPARCOS satellite safely revolves on its “degraded” orbit — after the exploit of the ESA technicians to rescue it from the faulty ignition of its apogeum boost motor — and regularly provides the information expected for reaching the initial aim of the project, one may turn to examine the possible exploitation of the final HIPPARCOS Catalogue.

In the present paper, we describe how double and multiple stars have been introduced in the Input Catalogue and what may be expected from their observation. We also try to evaluate how much the final HIPPARCOS data may influence future researches on these celestial bodies and what kind of ground–based observation programmes should be conducted in order to support the space results.
Differential Speckle Interferometry Applied to Double Stars
Authors: Petrov Romain G. , Lagarde Stephane
Published: July 2016

Differential Interferometry (DI) is the application of high angular resolution interferometric techniques to objects observed simultaneously at different wavelengths. When applied to unresolved double stars it makes it possible to measure the variation of the object photocenter with wavelength, which yields angular and spectral information well beyond the classical resolution limits. Signal–to–noise ratio analysis shows that, if DI experiments are limited by photon and speckle noise, the technique can be applied to a large number of double systems for the measurement of vectorial angular separations and of radial-velocity differences. With 4-m telescopes, there are a few tens of binary systems for which DI should permit the resolution and the measurement of the position angle of the rotation axis of at least one of the components. A preliminary experiment permitted a high SNR resolution of the double star Capella with a 1.52-m telescope and showed the current limitations of DI performances resulting from an imperfect correction of detector geometrical distortions.
SUSI’s Potential for Double Star Research
Authors: Davis John
Published: July 2016

The Sydney University Stellar Interferometer (SUSI) is currently undergoing commissioning and will soon commence its astronomical program in which observations of double stars will form a major component. With its 640-m long North–South array of input siderostats, the new instrument will have unprecedented angular resolution.
Speckle–Spectroscopic Studies of Late–Type Stars
Authors: Tokovinin A.
Published: July 2016

The existing and new observing techniques for combined speckle–spectroscopic studies of binary stars are briefly reviewed. The late–type dwarf stars are particularly rewarding since simultaneous spatial and spectroscopic resolution is possible for a large number of systems. A list of new candidates for the interferometric resolution is given. These studies can make an important contribution to the data on stellar masses and also provide some insight into the binary formation mechanisms when applied to multiple systems.
Astrometric Speckle Interferometry for the Amateur
Authors: Turner N.H. , Barry D.J. , McAlister H.A.
Published: July 2016

Because of the improvements in CCD detector quality and availability, as well as the increased performance and lower prices of PC compatible computers and digitizer boards, the time is ripe for getting amateur astronomers interested in speckle interferometry. Presented is a low–cost (under $1500 U.S., without computer) prototype astrometric speckle interferometry package suitable for use by amateur astronomers on their own telescopes. Table 1 lists the names and addresses of the manufacturers of the various products required as well as their prices.
Nuclear Weak Processes in Presupernova Stars
Authors: Ray A. , Kar T. , Sarkar S. , Chakravarti S.
Published: July 2016

The structure and the size of the core of massive presupernova stars are determined by the electron fraction and entropy of the core during its late stages of evolution; these in turn affect the subsequent evolution during gravitational collapse and supernova explosion phases. Beta decay and electron capture on a number of neutron rich nuclei can contribute substantially towards the reduction of the entropy and possibly the electron fraction in the core. Methods for calculating the weak transition rates for a number of nuclei for which no reliable rates exist (particularly for A > 60) are outlined. The calculations are particularly suited for presupernova matter density (p = 107 - 109 g/cc) and temperature (T = 2 - 6 × 109 °K). We include besides the contributions from the ground state and the known excited states, the Gamow-Teller (GT) resonance states (e.g. for beta decay rates, the GT+ states) in the mother nucleus which are populated thermally. For the GT strength function for transitions from the ground state (as well as excited states) we use a sum rule calculated by the spectral distribution method where the centroid of the distribution is obtained from experimental data on (p,n) reactions. The contribution of the excited levels and GT+ resonances turn out to be important at high temperatures which may prevail in presupernova stellar cores.
Infrared Spectroscopy of SN 1987A
Authors: Spyromilio Jason
Published: July 2016

Infrared spectra of SN 1987A have been obtained at the Anglo-Australian Telescope since the explosion of this supernova. I present highlights from this program which include the analysis of the molecular emission, the determination of the mass of 57Co in the ejecta and the analysis of the emission due to dust in the ejecta. I also show the spectrum of the supernova in the infrared 5 years after explosion.
ASCA Observations of Supernova Remnants
Authors: Tsunemi Hiroshi ,   The ASCA Team
Published: July 2016

We present here preliminary results of the ASCA satellite. ASCA is equipped with X-ray telescopes that can observe the energy range up to 12 keV. There are two types of detector systems: GIS and SIS. The energy resolution of the SIS is 130 eV (FWHM at 6 keV) and can resolve emission lines clearly. For the PV phase, we planned to observe about 150 sources. Among them, there are 23 SNR's, some of which are presented here. We will be able to study the evolution of thin hot plasma in the SNRs.
A Search for Trapezium Type Multiple Systems in T-Associations
Authors: Salukvadze G. N.
Published: July 2016

A high percentage of double and multiple stars among those in T-associations was first paid attention to by Prof V.A. Ambartsumian. Further at the beginning of sixties many investigators of variable stars (Kukarkin, Herbig et al.) paid attention to the necessity of studying duplicity of stars in T-associations. Just then the first lists of wide pairs in T-associations appeared.

We set a task to search for the Trapezium type multiple stars in T-associations involving the groupings of T Tau type variable stars from Kholopov’s list at a distance up to 500 pc. Such associations proved to amount 19, but out of them we succeeded in searching only in 12 ones.
Photographic observation of close binaries with large magnitude differences
Authors: Wedel Bernhard
Published: July 2016

Problems:

1.Size of diffraction image

2.Ross effect (shrinking of high exposed star images in the photographic emulsion)

3.Halo by diffusion of light in the photographic emulsion

4. Scintillation

Methods of improving the observation conditions are as following:

1.Deformation of diffraction image with quadratic or other formed masks

2.Diffraction gratings render possible a better measurement but don’t avoid Ross effect and halo of diffusion.

The halo of diffusion can reach much more of diameter than the original image.
Study of Spectroscopic Binaries with the Objective Prism Method
Authors: Gieseking Frank
Published: July 2016

The frequency distribution of SB’s over apparent visual magnitude emerging from the catalogue of Batten et. al. (1978) shows a very steep decrease of the number of spectroscopically detected SB’s already for such bright stars of magnitude 7. Considering the number of all stars in the individual magnitude intervals, we find a kind of completeness parameter of the spectroscopic surveys: If we scale it somewhat optimistically at 100% between 0 and 3 mag, we see a 50% decrease of the completeness of our knowledge of stellar radial velocities already for stars fainter than 4.5 mag.

This situation is mainly due to the fact that the measurement of radial velocities with conventional slit spectrographs is extremely laborious, requiring long exposure times at large telescopes for the exposure of only one spectrum at a time. – Therefore more efficient methods for radial velocity determinations of fainter stars are urgently needed.
Binary Star Observations with the Multi-Aperture Amplitude Interferometer
Authors: Currie Douglas G.
Published: July 2016

The basic goal of the Amplitude Interferometer Program at the University of Maryland has been to achieve very high angular resolution, far beyond the angular resolution which is normally permitted by the Earth’s atmosphere. This program is primarily directed to the observation of objects of astrophysical and astrometrical interest.

The initial general science objective has been the measurement of the angular diameters of various single stars at various wavelengths. As shall be discussed later, this has been achieved on the current equipment.

The second objective of the Amplitude Interferometer Program is the study of binary and multiple star systems. Some initial tests have been conducted to validate the approach and the expected accuracy using the existing Amplitude Interferometer (AI). However, detailed tests and/or a regular observing program require the multiplexing capablity of the next generation Amplitude Interferometer (the Multi-Aperture Amplitude Interferometer) in order to have a reasonable observing efficiency for the use of the telescopes which would be involved
The Solid State Area Scanner Photometer
Authors: Rakos Karl D.
Published: July 2016

The accuracy of the area scanning technique depends on observing conditions resulting from seeing, tracking irregularities of the telescope, photon and seeing statistics (integration time and the size of the telescope), and the atmospheric spectral dispersion of the stellar image in the spectral region used. In addition, the reduction method as well as the mechanical and optical quality of the telescope and photometer influence the accuracy of the results.

The tracking error of the telescope is usually larger than the observer believes. The amplitude of the periodic error of the worm gear is at best ± 0.5 arc sec with period length between 4 and 10 minutes, depending on the particular telescope. Figure 1 shows the tracking error for the ESO 50 cm and 100 cm telescopes. Other telescopes usually fit in between this two extremes.
Some Aspects of Visual Binary Star Orbit Determination
Authors: Harrington Robert S.
Published: July 2016

The problem under consideration is that of determining the seven elements (the vector ) characterizing the relative three-dimensional motion of the components of a binary star, using observations of the two-dimensional projection on the sky of the relative positions of those components as a function of time. Sooner or later a differential correction process is employed; therefore, this correction procedure will be reviewed first.

The basic approach is to derive a first estimate of the orbital parameters, form residuals from each of the observations, and assume these residuals represent a normally distributed random error, plus systematic errors due to an incorrect initial orbit. Expressing the residuals as functions of the orbital elements, these functions can be expanded in a Taylor series about the initial orbit and truncated after the first-order terms, giving the following approximate linear relation:
First results of Mercator observations of variable B stars
Authors: De Cat P. , De Ridder J. , Uytterhoeven K. , Davignon G. , Raskin G. , Cuypers J. , Schoenaers C. , Daszyńska-Daszkiewicz J. , Aerts C. , Van Winckel H. , Ausseloos M. , Broeders E. , De Meester W. , Vanautgaerden J. , Van Malderen R. , Vandenbussche B. , Acke B. , Decin G. , Decin L. , Kolenberg K. , Maas T. , De Ruyter S. , Reyniers M. , Reyniers T. , Van Kerckhoven C. , Waelkens C.
Published: July 2016

We report on the first results from observations of 28 variable B stars obtained with the new Mercator telescope (La Palma). Besides confirming the pulsational nature of known and candidate β Cephei and slowly pulsating B stars, we also present new candidate ellipsoidal variables and spotted stars.
On application of multi-colour photometry of δ Scuti stars
Authors: Daszyńska-Daszkiewicz J. , Dziembowski W.A. , Pamyatnykh A.A.
Published: July 2016

In δ Scuti star models the photometric amplitudes and phases exhibit a strong dependence on convection, which enters through the complex parameter,f, that describes the bolometric flux variation. We present a new method of extracting l and f from multi-colour data and apply it to several δ Scuti stars. The inferred values of f are sufficiently accurate to yield a useful constraint on models of stellar convection.
Eclipsing binaries in local group galaxies: Physical properties of the stars and calibration of the zero-point of the cosmic distance scale
Authors: Guinan Edward F. , Ribas Ignasi , Fitzpatrick Edward L.
Published: July 2016

We report on the progress of the program to study eclipsing binaries (EBs) in the Local Group galaxies. The primary goals of the program are to determine accurate distances and physical properties of the stars, and to probe the structure and evolution of the host galaxies. In particular, the distance to the Large Magellanic Cloud (LMC) is critically important because this nearby galaxy is used to calibrate most of the important cosmic distance indicators such as Cepheid and RR Lyr variables. Over the last several years, we have demonstrated that the distance of the LMC can be reliably measured using selected eclipsing binaries. The combined analyses of the UV/optical spectrophotometry, radial velocities, and light curves yield the stars’ physical properties (mass, radius, Teff, luminosity, metal abundance) and accurate (2–3%) distances. So far, the physical properties and distances of four LMC EBs have been completed and give a distance to the centroid of the LMC of 48.3 ± 1.6 kpc. Several additional EBs in the LMC and the Small Magellanic Cloud have been observed and are being analyzed. Also several LMC EBs have been observed with FUSE (92 – 119 nm) to further refine values of Teff and interstellar absorption. As an extension of these studies, 19–20th mag EBs in M31 are being observed photometrically and spectroscopically. The results of this extragalactic EB program are discussed along with plans to use EBs to study the host galaxy structure.
Non-Adiabatic Seismic Study of The Thin Convective Envelope of δ Scuti Stars
Authors: Dupret M.-A. , Grigahcène A. , Garrido R. , Montalban J. , Gabriel M. , Scuflaire R.
Published: July 2016

For δ Sct stars, the theoretical predictions of a non-adiabatic pulsation code are very dependent on the characteristics of the thin convective envelope of the models (Balona & Evers 1999). The treatment of the non-adiabatic interaction between convection and pulsation also has a significant impact on the results, particularly near the red edge of the instability strip. The non-adiabatic theoretical predictions can be tested upon observations by comparing them to the amplitude ratios and phase differences as observed in different color passbands (Dupret et al. 2003). In the first part of this paper, we compare the results obtained by adopting different treatments of convection in the interior and atmosphere models: mixing-length theory (MLT) and full spectrum of turbulence (FST) (Canuto et al. 1996, CGM). In the second part, we examine the problem of the interaction between convection and pulsation and compare the mode stability obtained with and without including time-dependent convection in our non-adiabatic code.
HRSP — A dedicated echelle reduction software package for Hercules
Authors: Skuljan Jovan
Published: July 2016

A collection of computer programs called the Hercules Reduction Software Package (HRSP) has been developed in the Department of Physics and Astronomy, University of Canterbury, for the data reduction of échelle spectra obtained with the Hercules spectrograph. The main goal in writing a dedicated software package for Hercules was to achieve a highly-optimized reduction process that would provide the basis of a pipeline reduction performed at the Mt John University Observatory. Since the spectrograph has no moving parts, the spectrum produced in the focal plane does not move or change, so that the same reduction procedure can be applied to all CCD images. An optimized routine written especially for Hercules is always much more efficient and reliable than any general-purpose software available. HRSP is written in C and the whole reduction procedure is performed on standard FITS files. A standard échelle reduction is applied, including the background and cosmic ray subtraction, order extraction, flat-fielding, normalization and wavelength rebinning. A special feature is the radial velocity determination by cross-correlation, which has been tested extensively over the past two years proving that Hercules is capable of delivering the high-precision radial velocities needed for detailed studying of binary stars, stellar pulsations, extra-solar planets and other related fields.
The Distance and Age of the Globular Cluster M5
Authors: Carney Bruce W. , Latham David W. , Jones Rodney V. , Beck Judy A.
Published: July 2016

Using optical and infrared photometry and echelle spectroscopy of variable V8 in the globular cluster M5, we derive a cluster distance of 6.8 kpc using the Baade-Wesselink method. This agrees with the prediction obtained for the cluster’s metallicity using a sample of 19 field stars studied by us and by Liu and Janes (this volume). It also agrees well with estimates for Mv obtained from statistical parallaxes of field stars. It agrees as well with the main sequence fitting procedure where we have used only HD 103095, the field halo dwarf with the most accurate trigonometric parallax (3% error), and which has a metallicity almost identical to that of M5. The star is also cool, hence unevolved, and is not a binary. Using the luminosity of the cluster’s main sequence, both Yale and Victoria isochrones yield a cluster age of 18 ± 3 Gyrs.
Period Doubling in Variable Stars: A Tentative Interpretation of Oberved Light Curves of Variable White Dwarfs and Mira Stars
Authors: Goupil M.J. , Baglin A. , Auvergne M.
Published: July 2016

Irregular pulsations are commonly observed in many groups of pulsating stars. An interpretation in terms of superposition of modes of pulsation is sometimes barely convincing when too many modes have to be considered and when unexpected ratios of frequenceis are observed.
The Luminosities of 13 Field RR Lyrae Stars: The Correlation with Metallicities
Authors: Liu T. , Joens K.A.
Published: July 2016

We have obtained UBVRI and JK photometry and radial velocities for 13 field RR Lyrae stars with a large range of metallicity. Our sample includes eleven ab-type and two c-type variables. The surface brightness method is applied to these RR Lyrae stars to determine their mean absolute magnitudes  as well as their distances and radii. We have used the Kurucz’s model atmospheres to provide metallicity- and gravity-dependent color-temperature transformations and bolometric corrections. Our results indicate a clear correlation between the luminosities of the RR Lyrae stars and their metallicities such that metal-poor RR Lyrae stars are more luminous.