bluuebunny/crossref_metadata_2025 huggingface dataset:
Working Group on Solar Eclipses
Authors: Rigutti M.
Published: July 2016

The working Group on Solar Eclipses regrets Dr J. Houtgast’s resignation as Chairman of the Group. However, Dr Houtgast will maintain his membership and continue to give his experience to the group.

The total eclipse of September 22,1968 was actively observed by many groups in spite of its short duration. Reports on the observations are expected to be given during the 1970IAU General Assembly.

A great deal of work has been done everywhere in view of the total eclipse of March 7, 1970.
15. Physical Study of Comets
Authors: Biermann L. , Vanýsek V. , Herzberg G. , Levin B. J. , Roemer E. , Whipple F. L. , Wurm K.
Published: July 2016

The partition of the subject matter of this report follows that of earlier reports. Drafts for individual sections or parts of such were contributed by C. Arpigny, L. Biermann, A. H. Delsemme, O. V. Dobrovolsky, L. Haser, G. Herzberg, B. J. Levin, Rh. Lüst, E. Roemer, V. Vanýsek, and K. Wurm. The overall editing was done by Mrs Rh. Lüst, V. Vanýsek, and the undersigned.

Before mentioning some of the more important developments it is noted that E. Roemer has continued to publish every few months short notes on comets in the Publications of the A.S.P. The annual reports inQuarterly Journal of the Royal Astronomical Societyhave been continued by B. G. Marsden and J. G. Porter.

Several collections of Russian papers have been published which give a survey of the work done in the U.S.S.R. The description of physical characteristics of comets which appeared from 1961— 1965 was continued by S. K. Vsehsvjatskij, who also completed a book onNature and Origin of Comets and Meteoritic Matter.
23. Carte du Ciel
Authors: Dieckvoss W. , Lacroute P. , Couderc P. , Dejč A. N. , Herget P. , Kox H. , Luyten W. J. , Sémirot P. , Wood H. W.
Published: July 2016

There seems to be a consensus of opinion that the useful life of the commission has come to an end with the achievement of the principal aim of the historical task of the Carte du Ciel, presenting an overall picture of the Heavens as to positions of the fixed stars up to a definite limiting magnitude. The French presidents in succession with great energy, supported by the IAU, succeeded in overcoming all obstacles and in finishing the printed Astrographic Catalogue. Remaining tasks of deriving definitive plate constants, eventually deriving reliable proper motions of all stars in the programme evidently rests with individual observatories or at other commissions of the Union within their proper frame of activities.

Following a suggestion presented at the meeting of the Executive Committee in September 1969 a decision was reached to abolish the Commission 23 proper by merging it with Commission 24 (Stellar parallax and proper motion), and a working group in the latter commission would become a suitable means to continue work on data furnished by the Astrographic Catalogue.

Several of those observatories still in possession of Carte du Ciel-astrographs are going on with proper motion (p.m.) work in their zones or are preparing to do so. The application of the astrographs to the programme of attachment of stars to galaxies according to A. N. Dejč’s method is in progress.
24. Stellar Parallaxes and Proper Motions
Authors: Luyten W. J. , Vasilevskis S. , Dejč A. N. , Lavdovskij V. V. , Lourens J. v. B. , Morgan W. W. , Murray C. A. , Strand K. Aa. , van de Kamp P.
Published: July 2016

At the Pulkovo Observatory a parallax programme has been started by Kanayev for 120 stars chosen mainly from Vyssotsky’s lists and the Leningrad list of multiple systems. Proper Motions relative to galaxies have been determined by Fatchikhin for 14669 stars in 85 different fields; the magnitude equation is being investigated and secular parallaxes as well as the solar apex and the constants of galactic rotation are being calculated. The general programme on absolute proper motions is being carried out by Dejč at Pulkovo, and at Cerro Calan in Chile, by Panteleyeva at Sternberg, and by Rahimov at Tashkent.
28. Galaxies
Authors: McVittie G. C. , Burbidge E. M. , Holmberg E. B. , Evans D. S. , Heeschen D. , Holmberg E. B. , Markarjan B. E. , Min-kowski R. L. , Schmidt M.
Published: July 2016

The volume of work published on extragalactic astronomy in the period August 1966 – July 1969 has been large. Limitations of space have precluded the writing of an all-inclusive report; in all sections some selection has had to be made. References are given, whenever possible, by the reference numbers of the Bulletin Signalétique of the CNRS of France, with the omission of the Section number: “2” for vols. 27 to 29 and “120” for vol. 30. A reference number preceded by J is taken from the Astronomischer Jahresbericht. When no reference numbers were available, abbreviated journal references have been given.
Working Group on the Magellanic Clouds
Authors: Thackeray A.D.
Published: July 2016

A Symposium on the Magellanic Clouds was sponsored by E.S.O. in Santiago, Chile, in 1969 March in connection with the dedication of the E.S.O. Observatory at La Silla. Review papers on the Clouds have been written by Westerlund and Bok (J. R. astr. Soc. Can., 63, 105).

Gascoigne (Mon. Not. R. astr. Soc., 146, 1) has prosecuted further his P-L work on Cloud cepheids and finds
V = 17·58 — 3·072 logP (7 LMC cepheids),
V = 17·73 — 2·879 logP (13 SMC cepheids)
while 25 SMC, 18 LMC and 13 galactic cepheids obey the Sandage relation
Mv = a – 3·609 logP + 2·52( – ).

This implies moduli of 18·73 (LMC) and 19·36 (SMC), but Gascoigne recommends, in the light of other evidence, adoption of moduli 18·75 (LMC) and 19·2 (SMC). The colours of SMC cepheids are 0.m1 bluer than those in the Galaxy and they may be somewhat underluminous for their periods.
29a. Working Group on Absolute Spectrophotometry
Authors: Oke J. B.
Published: July 2016

Two new and independent determinations of the absolute spectral energy distribution in αLyr have been completed during the last three years. The first of these by Hayes has been published in part (Wolff, Kuhi and Hayes, 1968). It was done at the Lick Observatory using the Crossley reflector and two ribbon-filament standard lamps. His published results are based on the old practical temperature scale which is based on a melting point for gold of 1336·16K. The new scale has been adjusted to agree as well as possible with the thermodynamic temperature scale and is based on 1337·59K for the melting point of gold. Hayes’ results have been adjusted to this new scale and are shown in Table 1. The numbers listed are — 2·5 log fv + const, when fv is the flux from αLyr in ergs s-1 cm-2 Hz-1. The results are normalized to 0·000 at λ5556.

The new calibration by Oke and Schild was carried out on Palomar Mountain. A four inch reflecting telescope was built and mounted with the prime focus scanner which was built for the 200-inch telescope. Three light sources were used (1) a ribbon-filament standard lamp calibrated with an accuracy of 2 % by the National Bureau of Standards was used from λ3300 to λ8000.
45. Spectral Classifications and Multi-Band Colour Indices
Authors: Fehrenbach Ch. , Westerlund B. , Bidelman W. P. , Haradze E. K. , Jaschek C.O.C. , Johnson H. L. , Morgan W. W.
Published: July 2016

Des classifications spectrales et des mesures photométriques ont été faites dans de nombreux Observatoires.

La classification à un seul paramètre, comme celle de Harvard, a été remplacée dans la plupart des cas par une classification bidimensionelle. La classification simplifiée est réservée aux étoiles faibles. Les classifications dans le système MK ont été faites dans de nombreux Observatoires et nous signalons les importantes listes d’Abastumani.

De nombreux astronomes ont recherché les étoiles riches ou pauvres en métaux, ce qui est l’amorce des classifications à trois paramètres. Des listes d’étoiles Am et Ap ont été publiées.
Working Group for the Worldwide Development of Astronomy Groupe De Travail Pour Le Developpement Mondial De L’Astronomie
Authors: Batten A. H.
Published: July 2016

During the past triennium some effort has been put into setting up what we hope will be an effective Working Group which currently has the above composition. Membership includes the Presidents of Commissions 38 and 46 ex-officio, so some regular change is built in every three years, as these Presidents change. Thanks are due to R. Kippenhahn, P. Lena, and J. Sahade, members of the original Working Group, who have retired from its active membership. The Chairman retains an extensive mailing list of about some 100 names. All those on that list will continue to receive the WG Newsletter. The present system is to mail one Newsletter annually, in April. At the time of writing, two such mailings have been made since the last General Assembly.
10. Distribution of electron concentration with
height and its influence on the propagation of
radio waves
Authors: Zhekulin L. A.
Published: July 2016

In this paper there is investigated the propagation of radio waves in a non-homogeneous ionized atmosphere with a dispersion of ionization obtained as a result of recent investigations into the structure of the ionosphere.

On the basis of the wave treatment of the problem, relations were found for the electric field intensity, expressed as Airy functions; and the results were compared with the approximate solution by geometric optics.
13. On Brightness Variations of Artificial Satellites
Authors: Tsesevich V. P.
Published: July 2016

In the preceeding reports an elegant theory of the origin of the elements has been outlined. This theory aims to be a comprehensive one. With the exception of D, Li, Be, B, the origin of all other nuclides is explained by thermonuclear reactions and subsequent neutron capture. But some difficulties arise in connexion with two groups of nuclides: the iron peak and the by-passed nuclei.
Improving the Accuracy of Radio Astrometry
Authors: Fey Alan L.
Published: July 2016

The International Celestial Reference Frame (ICRF) is currently realized by the radio positions of compact extragalactic objects obtained by the technique of Very Long Baseline Interferometry (VLBI). The positions of the defining sources with the highest quality are estimated to be accurate at the 0.25 milliarcsecond (mas) level. The limiting accuracy is thought to be due mostly to tropospheric propagation effects and by the apparent motions of the sources due to variable intrinsic structure. Increasing the accuracy of VLBI astrometry beyond current levels will require an improved understanding of the variable emission structures associated with compact extragalactic sources as well as improvements in the modeling of the Earth’s troposphere.
Densification of ICRS in the Optical by use of Old Pulkovo Observation Sets
Authors: Kumkova Irina I. , Bobylev Vadim V. , Bronnikova Nina M.
Published: July 2016

Modern tasks of high precision astrometry demand optical coordinate systems including more faint stars than are available now in current conventional systems (Hipparcos). For this purpose it is suggested to use old photographic observations accumulated in the Pulkovo Observatory. Extensive observational data have been obtained at Pulkovo Observatory during the last century in the framework of several programs, e.g. Pulkovo Galaxy plan, etc. Observations have been made with the Normal Astrograph from 1894 to the present. The data are investigated with the aim of extending the Hipparcos catalog to stars fainter than 11th magnitude. All available observations are taken into account. A description of the material considered is given. The distribution of the selected plates over the celestial sphere is shown as well. Coordinates of faint stars in the Hipparcos system are calculated for selected areas. The accuracy of computed star coordinates is analyzed. Results of the investigation are presented.
A New Optical Realization of the ICRS
Authors: Gontcharov George A. , Andronova Anna A. , Kornilov Edward V. , Titov Oleg A.
Published: July 2016

A new optical realization of the ICRS is built upon the data of the Hipparcos catalog and 60 observational and compiled astrometric ground-based catalogs of the 20th century reduced to the Hipparcos system. It is in print as two catalogs. The ‘Proper Motions of Fundamental Stars’ catalog (PMFS) contains proper motions of 4638 stars common to the Hipparcos and Basic FK5/FK5 Extension improved to the level of 0.5 mas. 1800 of the stars are the photocenters of stellar systems unresolved in the astrometric observations. The duplicity parameters of those systems were collected in the ‘Astrometric Binaries’ catalog (ABC). The photocenter nonlinear motions of several hundred of those astrometric binaries were detected and separated from their proper motions. The periods and amplitudes of several astrometric binaries are discussed in detail. This research will be continued for all Hipparcos stars observed from the ground in the 20th century. The web site is http://www.geocities.com/georgegontcharov/
On the Reference Pole for Earth Orientation and UT1
Authors: Mathews P.M. , Herring T.A.
Published: July 2016

We show how the study of variations in orientation of a terrestrial reference system (TRS) in space may be done directly in terms of the motion of the pole of the TRS and rotation around it, and how a separation of these variations into low frequency and high frequency (retrograde and prograde diurnal, semidiurnal, · · · ) bands enables one to characterize and model variations belonging to the various bands and to estimate them simultaneously from observational data by a uniform procedure. Introduction of the Celestial Ephemeris Pole (CEP) or other Celestial Intermediate Pole (IP) is not only unnecessary, but also gives rise to needless debate as to whether variations due to particular causes are to be included in the celestial motion of the IP or in its terrestrial motion, and leaves the question of estimation of high-frequency signals in either frame unresolved. In regard to UT1, we point out that the “correction terms” through which the concept of the nonrotating origin is implemented emerge naturally from fundamental kinematical relations, and use this observation to identify the correction terms to be employed when the Earth orientation parameters are defined in relation to the pole of the TRS rather than an IP.
A New Nutation Model Of Nonrigid Earth With Ocean And Atmosphere
Authors: Huang Cheng-li , Jin Wen-jing , Liao Xing-hao
Published: July 2016

By integrating the truncated complex scalar gravitational motion equations for an anelastic, rotating, slightly elliptical Earth, the complex frequency dependent Earth transfer functions are computed directly. Unlike the conventional method, the effects of both oceanic loads and tidal currents are included via outer surface boundary conditions, all of which are expanded to second order in ellipticity. A modified ellipticity profile in second order accuracy for the non-hydrostatic Earth is obtained from Clairaut’s equation and the PREM Earth model by adjusting both the ellipticity of the core-mantle boundary and the global dynamical ellipticity to modern observations. The effects of different Earth models, anelastic models, and ocean models are computed and compared. The atmospheric contributions to prograde annual, retrograde annual and retrograde semiannual nutation are also included as oceanic effects. Finally, a complete new nutation series of more than 340 periods, including in-phase and out-of-phase parts of longitude and obliquity terms, for a more realistic Earth, is obtained and compared with other available nutation series and observations.
Influence of Adopted Nutation Model on VLBI NEOS-Intensives Analysis
Authors: Titov Oleg
Published: July 2016

Very Long Baseline Interferometry (VLBI) provides information about the Earth’s rotation. Various observational programs have operated for different specific purposes since 1983. The purpose of the NEOS-Intensive program is to make observations of Universal Time (UT1–UTC). Short observational sessions (1-2 hours) include only the transcontinental baseline (Wettzell - NRAO20). 20–30 individual scans are performed during the observational time. Only five parameters, wet delay for the reference station, wet delay for the second station, clock offset for the second station, clock rate for the second station, and UT1–UTC are considered in the parametric model.

The purpose of this paper is to investigate the influence of the adopted nutation model on the UT1–UTC estimates. VLBI data from the NEOS-Intensives have been analyzed using the OCCAM 3.4 software. All reduction calculations are in accordance with the IERS Conventions 1996 (McCarthy, 1996).
Report on Astronomical Constants
Authors: Fukushima Toshio
Published: July 2016

Recent progress in the determinations of astronomical constants is reviewed. First is the latest estimation of the general relativistic scale constants, LC, LG, and LB (Irwin and Fukushima, 1999). By reestimating the uncertainty, the value of the first constant is given as LC = 1.480 826 867 4 × 10–8 ± 1.4 × 10–17. Also noted is the rigorous relation among these three, LB = LC + LG – LCLG. Based on the latest determination of the geoidal potential W0 in the IAG 1999 Best Estimate of Geodetic Parmeters (Groten, 1999), LG and LB were reevaluated as LG = 6.969 290 09 × 10–10 ± 6 × 10–18 and LB = 1.550 519 767 3 × 10–8 ± 2.0 × 10–17. Since LG is roughly related to W0, a proposal to fix its numerical value is presented in order to remove the geophysical ambiguity in its evaluation in the future. In that case, LG becomes a defining constant for the scale difference between the geocentric and terrestrial coordinate systems. While LC and LB remain as a primary and derived constant, respectively. Next is the correction to the current precession constant, Δp. The recent estimates of Δp based on Very Long Baseline Interferometry (VLBI) observation seem to converge to a value close to –0.30″/cy (Mathews et al., 2000; Petrov, 2000; Shirai and Fukushima, 2000; Vondrák and Ron, 2000). Unfortunately this is significantly different from –0.34″/cy, the latest value determined from the Lunar Laser Ranging (LLR) data (Chapront et al., 1999). The difference is roughly ten times larger than the sum of their formal uncertainties. Since the cause of this difference is not clear, we first arranged the best estimates based on VLBI and LLR techniques, respectively, then took a simple mean of these two best estimates, and recommend it as the current best estimate. The value derived is p = 5 028.78 ± 0.03 ″/cy. Similar estimates were given for some other quantities related to the precession formula; namely the correction to the obliquity rate of the IAU 1976 precession formula (Lieske et al., 1977), Δε1 = (–0.024 5 ± 0.002 5) ″/cy, and the offsets of the Celestial Ephemeris Pole of the International Celestial Reference System, Δψ0 sin ε0 = (–17.5 ± 0.8) mas and Δε0 = (–5.2 ± 0.4) mas. As a result, the obliquity of the ecliptic at the epoch J2000.0 was estimated as ε0 = 23°26′21.″405 6 ± 0.″000 5. The draft IAU 2000 File of Current Best Estimates of astronomical constants, that is to replace the 1994 version (Standish, 1995) or maybe even the formal IAU 1976 System of Astronomical Constants (Duncombe et al., 1977), after discussion at the 24th General Assembly of the IAU is presented.
Incompressible MHD Turbulence
Authors: Goldreich Peter
Published: July 2016

The inertial range of incompressible MHD turbulence is most conveniently described in terms of counter propagating waves. Shear Alfvén waves control the cascade dynamics. Slow waves play a passive role and adopt the spectrum set by the shear Alfvén waves. Cascades composed entirely of shear Alfvén waves do not generate a significant measure of slow waves. MHD turbulence is anisotropic with energy cascading more rapidly along k⊥ than along k‖. Anisotropy increases with k⊥ such that the excited modes are confined inside a cone bounded by . The opening angle of the cone, , defines the scale dependent anisotropy. MHD turbulence is generically strong in the sense that the waves which comprise it are critically damped. Nevertheless, deep inside the inertial range, turbulent fluctuations are small. Their energy density is less than that of the background field by a factor θ2(k⊥) « 1. MHD cascades are best understood geometrically. Wave packets suffer distortions as they move along magnetic field lines perturbed by counter propagating wave packets. Field lines perturbed by unidirectional waves map planes perpendicular to the local field into each other. Shear Alfvén waves are responsible for the mapping’s shear and slow waves for its dilatation. The former exceeds the latter by θ−1 (k⊥) » 1 which accounts for dominance of the shear Alfvén waves in controlling the cascade dynamics.
Looking into Pulsar Magnetospheres
Authors: Lyutikov Maxim
Published: July 2016

Diffractive and refractive magnetospheric scintillations may allow direct probing of the plasma inside the pulsar light cylinder. The unusual electrodynamics of the strongly magnetized electron-positron plasma allows separation of the magnetospheric and interstellar scattering. The most distinctive feature of the magnetospheric scintillations is their independence of frequency. Diffractive scattering due to small scale inhomogeneities produces a scattering angle that may be as large as 0.1 radians, and a typical decorrelation time of 10−8 seconds. Refractive scattering due to large scale inhomogeneities is also possible, with a typical angle of 10−3 radians and a correlation time of the order of 10−4 seconds. Some of the magnetospheric propagation effects may have already been observed.
Multifrequency Polarization Variations in 0917+624
Authors: Qian S.J. , Kraus A. , Krichbaum T.P. , Witzel A. , Zensus J.A.
Published: July 2016

Intraday variability in compact flat-spectrum radio sources has been intensively studied in recent years. For most IDV events the apparent brightness temperatures derived from the observed timescales are in the range of Tb,app ~ 1016−18 K. For extremely rapid variations, Tb,app can reach up to ~ 1021 K (e.g. Kedziora-Chudczer et al., 1997). Refractive interstellar scintillation may be the most likely extrinsic mechanism (Rickett et al., 1995; Qian, 1994a; Qian, 1994b). Especially for the case of extreme Tb,app (> 1018 K) RISS may be dominant (Dennet-Thorpe and de Bruyn, 2000). However, some IDV events with Tapp ~ 1017−18 K show evidence for an intrinsic origin e.g. the correlated radio-optical intraday variations observed in the BL Lac object 0716+714 (Wagner and Witzel, 1995, Qian et al, 1996). It seems important to distinguish between IDV which is a phenomenon intrinsic to the compact radio sources and IDV which is primarily due to RISS. Multifrequency polarization and VLB I observations would be most helpful (Gabuzda and Kochanev, 1997).
ISS of Polarized Compact Extragalactic Radio Sources
Authors: Rickett Barney
Published: July 2016

It is shown that the detailed inter-relations of the 8.6 GHz IDV in Stokes’ parameters I, Q and U of the quasar 0405-385, as quantified by their auto and cross correlations, can be successfully modelled by interstellar scintillation (ISS) of a double source with two components separated by about 10 micro-arcseconds. Though this is not a unique source model it confirms that ISS can explain quantitatively the rapid variations in both flux and linear polarization. Thus there is no evidence in support of an intrinsic component in the IDV.
IPS Observations at Miyun Station, BAO
Authors: Wu J. , Zhang X. , Zheng Y.
Published: July 2016

IPS observations have recently begun at Miyun Station, Beijing Astronomical Observatory. This paper briefly describes the radio telescope at Miyun Station, discusses the observation and the data reduction procedures, and presents the preliminary results of observations on IPS source 3C48.
VLA Observations of Angular Broadening Close to the Sun
Authors: Gothoskar Pradeep , Anantharamahaia K.R. , Desai Ketan , Rao A.P.
Published: July 2016

We present synthesis imaging of scatter-broadening of radio sources carried out using the Very Large Array (VLA) at six radio frequencies during the period of solar minimum. Three compact radio sources were observed from 2 to 16 solar radii around the sun. The data indicate highly anisotropic scattering. The scatter-broadening was estimated from the area of the scattered image and was found to be factor of two lower and orientation of magnetic fields was closer to the radial direction. Present observations confirm the variation of scatter-broadening with solar elongation.
On the Cable Car Feed Support Configuration for FAST
Authors: Gexue Ren , Qiuhai Lu , Zhou Zhou
Published: July 2016

This paper introduces the cable car feed support configuration for China’s FAST project. Recent advances on the mechanics of the proposed supporting structure and the control of the Stewart platform for secondary feed stabilization are presented. Difficulties associated with the configuration are also discussed.
Trying to Enlarge the Sky Coverage of the FAST
Authors: Wu Shengyin , Wang Shouguan , Mao Yukuan , Su Yan
Published: July 2016

The proposed FAST project is a novel giant spherical radio telescope, with active elements which form a temporary paraboloid to track radio objects in the sky. Efforts have been made to extend the limited sky coverage that is a characteristic disadvantage of Arecibo-style radio telescopes. Three measures under investigation are introduced in this paper. The expected performance of the telescope is described, and a brief comparison is made with some of the largest existing radio telescopes.
V652 Her: Evidence that White Dwarf Mergers Really do Happen
Authors: Jeffery C. Simon
Published: July 2016

V652 Herculis is a pulsating B star with a mass of about 0.6 M⊙ and a luminosity of some 1000 L⊙. Its uniqueness is defined by a surface which is predominantly (99%) CNO-processed helium. Precise measurements of its pulsation properties have provided direct tests for stellar pulsation and evolution models. Simulations of the merger of two helium white dwarfs are very successful in explaining its origin.
Criterion for Dynamical Instability of Mass Transfer in Binary Evolution
Authors: Han Zhanwen , Podsiadlowski Philipp , Tout Christopher A.
Published: July 2016

Using Eggleton’s code, we performed a series of binary evolution calculations in order to investigate the criterion for dynamical instability of mass transfer in binaries. In these calculations, we took the donor’s mass on the zero-age main sequence (ZAMS) from 0.8 to 1.9 M⊙. For each mass, we systematically varied the mass of the core at the beginning of mass transfer and the mass of the companion star. We assumed that mass transfer was completely non-conservative and that all the mass that was lost from the system carried with it the orbital angular momentum of the accreting component. We found that the critical mass ratio, above which mass transfer is dynamically unstable, is from 1.1 to 1.3 in these red-giant binary systems.
TU Muscae and the Early-type Overcontact Binaries
Authors: Terrell Dirk
Published: July 2016

A simultaneous photometric and spectroscopic analysis of the purported early-type overcontact binary TU Muscae is presented. With a well-behaved light curve and a mass ratio far from unity, if TU Mus is indeed an overcontact system, it presents an interesting challenge for 3-D stellar evolution codes, like the Djehuty code, that will be applied to early-type overcontact binaries. The analysis shows TU Mus is slightly overcontact and that a detailed treatment of the reflection effect is important for modeling the light curves.
V838 Monocerotis — a Newly Discovered, Very Peculiar, Slow Nova-Like Object
Authors: Rauch Thomas , Hauschildt Peter , Asplund Martin , Gredel R. , Käufl H.-U. , Kerber Florian , Rosa Michael , Starrfield Sumner G. , Wagner R. Mark , Williams Robert E.
Published: July 2016

The eruptive variable V838 Mon was discovered on Jan 6, 2002. Due to a subsequent phase of almost constant brightness and a spectral appearance which is unlike classical novae, speculations have been made about its nature. Either it was a very peculiar, slow nova defining a new class, an eruptive event in an evolved star as in the case of Sakurai’s Object but in a much earlier phase, or something completely different.
Strange New Magnetics from the Sloan Digital Sky Survey
Authors: Szkody Paula
Published: July 2016

The first two years of the Sloan Digital Sky Survey have discovered over 50 new cataclysmic variables, of which four are confirmed Polars, two others are likely candidates and several others are good candidates for Intermediate Polars or SW Sex stars. Several systems have unusual characteristics, including large amplitude, narrow cyclotron humps indicating a very low temperature shock on a cool white dwarf, or very deep eclipses. Although SDSS is finding a variety of systems, it is ideal for picking up the low mass transfer rate magnetic systems missed in X-ray surveys and in past optical surveys with brighter limits. Thus, it is providing us with a clearer picture of the range of conditions existing in magnetics CVs.
XMM–Newton observation of the Polar BL Hyi
Authors: Matt Giorgio , de Martino Domitilla , Baldi Alessandro
Published: July 2016

A short serendipitous XMM–Newton observation of BL Hyi is presented.
Two Types of X-ray Spectra in Cataclysmic Variables
Authors: Mukai K. , Kinkhabwala A. , Peterson J. R. , Kahn S. M. , Paerels F.
Published: July 2016

We present Chandra HETG spectra of seven cataclysmic variables, including four intermediate polars. We find that they divide unambiguously into two distinct types. Spectra of the first type (nonmagnetic systems and EX Hya) are remarkably well fit by a simple cooling flow model, which assumes only steady-state isobaric radiative cooling. The maximum temperature, kTmax, and the normalization, which provides a highly precise measurement of the accretion rate, are the only free parameters of this model. Spectra of the second type (the three other IPs) are grossly inconsistent with a cooling flow model. They instead exhibit a hard continuum, and show strong H-like and He-like ion emission but little Fe L-shell emission, which is consistent with expectations for line emission from a photoionized plasma. Using a simple photoionization model, we argue that the observed line emission for these sources can be driven entirely by the hard continuum. The physical significance of these two distinct types of X-ray spectra is also explored.
The Fe XXII I(11.92 Å)/I(11.77 Å) Density Diagnostic
Authors: Mauche Christopher W. , Liedahl Duane A. , Fournier Kevin B.
Published: July 2016

Using the Livermore X-ray Spectral Synthesizer, which calculates spectral models of highly charged ions based on HULLAC atomic data, we investigate the temperature, density, and photoexcitation dependence of the I(11.92 Å)/I(11.77 Å) line ratio of Fe XXII. Applied to the Chandra HETG spectrum of the intermediate polar EX Hya, we find that the electron density of its Te ≈ 12 MK plasma is orders of magnitude greater than that observed in the Sun or other late-type stars.
Spectroscopic and Photometric Observations of the Magnetic Cataclysmic Variable TX Col
Authors: Mhlahlo Nceba , Potter Stephen B. , Buckley David
Published: July 2016

Simultaneous photometry and spectroscopy of the Intermediate Polar TX Col were obtained in order to investigate its accretion mode and dynamics. The spectroscopic and photometric power spectra of TX Col are observed to change on relatively short timescales. Spectroscopy reveals a dominant periodicity at the orbital period (5.69 hr) and a spin period of 1909 s in radial velocities, while line equivalent widths show a strong periodicity at the beat period (2106 s). It is the first time that the orbital period has been detected in optical wavelengths.
FUSE Results on Magnetic CVs: VV Pup, YY Dra, LS Peg and DW UMa
Authors: Szkody Paula , Hoard Donald W. , Linnell Albert P. , Long Knox , Schmidt Gary , Sion Edward M.
Published: July 2016

In Cycles 2 and 3, we obtained FUSE observations of the Polar VV Pup, and the IP/SW Sex stars YY Dra, LS Peg and DW UMa. The spectra show a wide range of line intensities and structure. The phase-resolved spectra in each case reveal interesting properties about the hot accretion zones.
Radiation-hydrodynamic Models of the Accretion Spots in Magnetic Cataclysmic Variables
Authors: Beuermann K.
Published: July 2016

The structure of the near-polar accretion spots on accreting magnetic white dwarfs has been studied theoretically and observationally in numerous papers over the last decade. Detailed treatments are available for the regime of low mass flux, usually termed the bombardment case, and for higher mass fluxes which create a strong shock standing above the photosphere of the white dwarf. No general treatment is so far available for the case of shocks buried deep in the photosphere. I review the theoretical foundations, present some applications of theory, and discuss in short the open questions which still need to be addressed.
Tomography of AM Her and QQ Vul
Authors: Staude A. , Schwope A. D. , Hedelt P. , Rau A. , Schwarz R.
Published: July 2016

We present optical high-resolution spectroscopy of AM Her and QQ Vul. Making use of indirect imaging techniques (Doppler and Roche tomography), we are able to make details visible, which a model of these systems has to be able to account for. Especially the emission line data cannot be explained by current models of polars.
On the Evolution of the Nova-like Variable AE Aquarii
Authors: Meintjes P. J.
Published: July 2016

It is shown here that the peculiar properties of AE Aqr can can be accounted for if the mass transfer from an evolved 0.7M⊙ secondary K4-5 star (qi ≈ 0.8, i.e. < 1) initiated when the orbital period of the binary was Porb,i ≈ 8.5 hours and the white dwarf period P*,i ≈ 1 hour. This resulted in a significant amount of orbital angular momentum being accreted by the white dwarf in an initial discless spin-up phase towards P* ≈ 0.1 Porb,i. This destabilized the mass transfer, resulting in a run-away mass transfer from the secondary that lasted for approximately 104 years, with the orbital period evolving to Porb ≈ 11 hours until a critical mass ratio of qcrit = 0.73 had been reached. In this phase the mass transfer from the secondary occurred at a rapid rate of approximately Ṁ2 ≈ 1020 g s-1, resulting in an accretion disc which spun-up the white dwarf to a period of approximately P* ≈ 33 s. For all q ≤ qcrit = 0.73 the mass transfer proceeded on the thermal time scale of the secondary star, i.e. at a much slower rate, resulting in the binary converging and forcing AE Aqr into the propeller phase. Applying stellar wind theory, this allow an estimate of the polar magnetic field of the secondary star, which is of the order of B° ≈ (1600 – 2000) G. It has been shown here that the duration of mass transfer phase q = qcrit → 0.67 (now) lasted for approximately tṀ2 ~ 107 years, similar to the spin-down time scale of the white dwarf, tsd = P*/P* ≈ 107 years. The propeller ejection of matter in the current phase results in the dissipation of mhd power of Lmhd ≈ 1034 erg s-1, probably channeled into mass ejection and non-thermal activity. This explains the non-thermal outbursts that are observed in radio wavelengths, and occasionally also in TeV energies, from AE Aqr.
Note About a New Evaluation of the Direct Perturbations of the Planets on the Moon’s Motion
Authors: Standaert D.
Published: July 2016

The aim of this paper is to present the principal features of a new evaluation of the direct perturbations of the planets on the Moon’s motion. Using the method already published in Celestial Mechanics (Standaert, 1980), we compute “a first-order theory” aiming at an accuracy of the order of the meter for all periodic terms of period less than 3 500 years.

From an external point of view, we mean by that:

a)

keplerian orbits for the planets,

b)

the ELP-2000 solution of the Main Problem proposed by Mrs. Chapront (Chapront-Touzë, 1980),

c)

the first-order derivatives with respect to the constants of motion of the SALE theory of Henrard (Henrard, 1979).

On the other hand, from an internal point of view, the computations include:

d)

the development in Legendre polynomials not only to the first-order in (a/a'), but also the following ones (up to the sixth-order for Venus, for example),

e)

the contributions of the second-order in the Lie triangle,

f)

second-order contributions coming from the corrections of the mean motions due to the planetary action.
Comments on the Effect of Adopting New Precession and Equinox Corrections
Authors: Williams J. G. , Melbourne W. G.
Published: July 2016

The new astronomical constants being introduced for 1984 affect the derived values of UT1 and terrestrial longitudes differently for the space techniques than for the optical techniques. The new sidereal time equation has been defined to avoid a discontinuity in UT1 as obtained by the established techniques. However, this definition does introduce a discontinuity in both the terrestrial longitude system and the UT1 rate derived by the space techniques which have an inertial celestial reference frame rather than a stellar catalog frame. The use of consistent expressions for precession and Greenwich Mean Sidereal Time will not eliminate differences between the inertial and classical optical techniques. Only improvements in the accuracy of the precession constant and equinox offset and drift will bring about consistency. Improvements in the precession constant can be expected in the next few years. The inertial techniques will exhibit shifts in the derived UT1 rate and terrestrial longitude system with each change in the precession constant if Greenwich Mean Sidereal Time is referenced to the mean equinox of date, as is the present practice, but would be stable if the reference is a fixed equinox. The latter choice is recommended.
Determination of Coordinates for the Orroral Lunar Ranging Station
Authors: Morgan P. , King R.W.
Published: July 2016

Using models of the Earth-Moon system developed from analysis of 10 years of laser ranging observations from the McDonald Observatory, we have analyzed observations obtained by the Orroral Lunar Ranging Station since April 1978. Normal point residuals from many of the observations performed before April 1980 using a 20 ns, mi tiple-mode laser pulse are discreetly spaced, as multiples of 6 ns, and may have been corrupted by variations in pulse shape. Further evaluation is required before these observations are used in scientific analyses. Observations performed during the MERIT Short Campaign (August - October 1980) using a 6 ns, single-mode pulse are apparently reliable. Using 27 single photoelectron events, obtained on 7 nights during this period, we have estimated the coordinates of Orroral, with respect to McDonald, with uncertainties of 1-2 m in cylindrical radius and longitude and 5-10 m in z-axis distance.
VLBI Measurements of Radio Source Positions at Three U.S. Stations
Authors: Ye Shu-Hua
Published: July 2016

Results of VLBI measurement of 14 radio source positions at three U.S. stations during the MERIT short campaign is presented. Comparisons with other solutions are given, together with the comparisons between several radio source catalogues.

During the MERIT short campaign, several observatories cooperated in VLBI measurements organized jointly by the U.S. National Geodetic Survey (NGS) and the National Aeronautics and Space Administration (NASA). There were two 7-day observations arranged from Sept. 26 to Oct. 2 and from Oct. 16 to Oct. 22, with time span nearly 23 hours per day. Details of the observation and data reduction have been published elsewhere (1). This paper deals with radio source positions determined by three U.S. stations, the Haystack Observatory, the Harvard Radio Astronomy Station (HRAS) and the Owens Valley Radio Observatory (OVRO).
Expansion of the Disturbing Function by Factorization
Authors: Broucke R. , Presler W.
Published: July 2016

We present an expansion of the disturbing function for the third-body perturbations in the form , where ε is the ratio of semi-major axes (a/a’) and Xnm and Ynm depend only on the five elements e, i, ω, Ω, of the satellite while and depend on the corresponding elements of the perturbing body. Each one of the four functions X and Y is represented as a product of two factors as opposed to three factors in our previous publication of this subject (Broucke, 1981). We develop several relations for the construction of the X and Y-series. These series are relatively short and can be computed in advance and stored on magnetic tape, for instance.
The Future of Astronomical Literature
Authors: Abt Helmut A.
Published: July 2016

This is a historic occasion for astronomical librarians because, in many cases, this is your first opportunity to meet each other in person and to discuss mutual problems. Astronomical librarians have always been more internationally minded than most librarians and people, because you are used to exchanging literature with even the most distant observatories and countries, independent of political and transportation barriers. However, some of the problems that you now face cannot be solved alone, so we meet partly to cooperate in finding solutions. This meeting was also planned to learn what is being done in new technologies and information retrieval so that we will become aware of current and coming opportunities and changes.
Astronomical Literature Acquisitions in the U.S.S.R
Authors: Dluzhnevskaya Olga B.
Published: July 2016

Ideas are presented relating to the problems encountered by astronomical libraries in the Soviet Union.
Problems of International Acquisitions
Authors: de Guerra Selma
Published: July 2016

Both problems and solutions are included in a contribution to a panel discussion on the free (and not so free) flow of astronomy/astrophysics publications across political boundaries.
Astronomy and Astrophysics Abstracts - Present Status and Future Plans
Authors: Schmadel L. D.
Published: July 2016

The methods of the abstracting and indexing work at the ‘Astronomisches Rechen-Institut’ are briefly outlined. Actually used procedures as well as projected developments of the bibliographic data base ‘Astronomy and Astrophysics Abstracts’ are summarized.
Maintaining the Historical Record
Authors: Corbin Brenda G.
Published: July 2016

The session on Conservation of Historical Materials covered preservation of library materials and historical instruments, and included an account of how one observatory set up a state of the art conservation laboratory and program. Mark Roosa of the Library of Congress told us in a very lively way what we should be doing to preserve current and rare library materials. Perhaps many of us knew some of these basic principles, but it was good to be reminded of them so that we can more actively apply them in our libraries. Janet Dudley (formerly of the Royal Greenwich Observatory) described the magnificent conservation project which was set up at RGO a few years ago. It would be ideal if such projects could be undertaken at all astronomy libraries which have rare books and archival materials. However, it is apparent that finding funds for conservation is very difficult in many institutions. Magda Vargha of the Konkoly Observatory described the conservation of historical instruments, and reminded us of the terrible things which can happen to these instruments if they are not considered within the historical perspective of the institution.
Use of Computers in Small Libraries
Authors: Sachtschal E.
Published: July 2016

The library of the European Southern Observatory exists in its holdings since about 1970. The library is still a small one. It contains about 15–20000 books, 240 journal titles, approximately 70 m shelf-space for Observatory Publications and has about 220 square meters surface area. With about the same size we have a second library in La Silla in Chile, the mountain where our telescopes are installed. In Garching we have one and a third (!) librarian(s) and in Chile one librarian as staff. The question is: is it possible and is it necessary to computerize such small libraries and how can we do it with such limited personnel? The answer is yes; it is possible and even worthwhile.
Conversion of the Anglo-Australian Observatory Library Card Catalogue using PC Software
Authors: Shobbrook Robyn M.
Published: July 2016

A commercial software package has been used on a personal computer for the conversion of the Anglo-Australian Observatory card library catalogue. The software is sophisticated but has proven to be extremely flexible and easy to use for any library management task. The software is available at three levels; the AAO has the top level which allows for eight different databases on the one system. Each record may contain up to nine pages or screens of information and there is also a thesaurus facility. Although a multi-user system was preferred the cost of the software was out of the question. The flow-chart (Fig 1.) describes how a multi-user system was created from software designed for a single-user PC. The main files have been down-loaded in accession number order onto the VAX 11/780 minicomputer and these may be accessed on any terminal either at the laboratory headquarters at Epping in Sydney or at the telescope site at Coonabarabran 500 kms north-west of Sydney. The ‘read-only’ files can be searched using the VAX edit commands and a VAX sort facility is available for a listing of selected items if required. As a substitute measure this is proving to be most useful. Later when the files are too large and searching becomes slow it may be possible to purchase additional copies of the commercial PC software which allows more sophisticated search procedures.
Resource Sharing in the CSIRO Division of Radiophysics Library
Authors: Davies Jenny
Published: July 2016

The CSIRO Divison of Radiophysics was established as the CSIRO Radiophysics Laboratory in 1939 to conduct radar research. After World War 2 experimental radar instruments were applied to the developing field of radio astronomy. Current areas of research for the Division, which is host to the new Australia Telescope (AT), are radio astronomy, antenna technology, satellite communications, signal processing and microelectronics.

The AT has three observatory sites, all in New South Wales: six antennas near Narrabri, over 500 km from Sydney, the 27-year-old Parkes observatory, 350 km from Sydney, and one antenna near Coonabarabran, between Parkes and Narrabri. Most staff are located at the Division’s headquarters in Sydney, where the main library is also located, and small collections are maintained at the Parkes and Narrabri observatories.
Resource Sharing: Information Sharing
Authors: Motais de Narbonne Anne-Marie
Published: July 2016

When we speak of resource sharing, we mostly mean document sharing through union catalogues, list exchanges, interlibrary loans, cooperative acquisition programs... Yet, the first and primary condition of the library network efficiency is information sharing.

Libraries have been quite successful in this field for the last decades but, nowadays, new technology such as electronic mail or telefax offers unequaled facilities to set up and promote a permanent and world wide program of information exchanges liable to meet the increasing needs of punctual responses. From an eight year experience at Paris Observatory library which has been hosting the French national service CADIST [Centre d’acquisition et d’information scientifique et technique], we can assert that, outer demands of informations being at the same time useful information sources, such a quick answer service does participate to the improvement of the inner service efficiency.
Colllection Developing at Purple Mountian Observatory: Seeking Exchanges of Foreign Astronomy Serials
Authors: Bi-kun Huang
Published: July 2016

Foreign exchange of astronomical serials as a means of developing a collection at the Purple Mountain Observatory is discussed.