bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Variations of the Hα Line of the Be Star o And
Authors: Briot D. , Chauville J. , Guerrero G.
Published: July 2016

Omicron Andromedae is a multiple system composed of at least four components. The main component “A” is a variable Be star (B5II-III). The variations of this star are multiform: the circumstellar emission and absorption can vary drastically and can even disappear and reappear later, whereas changes in magnitude are also observed (see e.g. Sareyan et al., 1998). Rapid Spectroscopic and photometric variations are observed as well. As explained below, the rapid Spectroscopic variations of the Hα line observed in 1992 during a phase of moderate emission are very special (Briot et al., 2001). Then the emission of о And increased, so another program of observations of the Hα line was performed to investigate its rapid variations during different emission phases. We present here some preliminary results.
Non-Adiabatic Quantities in δ Scuti and γ Dor Stars: a Comparison between Observations and Theoretical Non-Adiabatic Models
Authors: Garrido R. , Moya A. , Claret A.
Published: July 2016

Phase lag, ψT and R, a parameter measuring the departure from adiabaticity, can be derived directly from multicolor photometry. The same quantities can also be calculated from theoretical non-adiabatic pulsation models. We present here some preliminary theoretical results which indicate that these quantities depend on the mixing length parameter used to treat convection in the standard ML theory. The comparison favours models with α values between 1 and 1.5Hp. Non-adiabatic models also predict the observed phase lags for the newly discovered α Dor g-mode pulsating stars.
Mode Identification in the δ Scuti Star 20 CVn
Authors: Chadid M. , Mathias P. , De Ridder J. , Aerts C.
Published: July 2016

We present a new Spectroscopic study of the δ Scuti star 20 CVn in order to solve the controversy on the type of pulsation mode of this object.
Differential Time-Series Photometry of BL Camelopardalis: Revisited
Authors: Kim Chulhee , Jeon Y.B.- , Kim S.-L.
Published: July 2016

New differential time-series observations of the white dwarf BL Camelopardalis were obtained using the B and V filters. It was confirmed that BL Cam is a double star but the effect of the secondary star on the periods is almost negligible. The (O-C) diagram and periods were analyzed.
Frequency Analysis of a Subset of Fundamental Mode RR Lyrae Stars from the MACHO Project Large Magellanic Cloud Database
Authors: Welch D.L. , Kovács G. , Cook K.H. , Alcock C. , Allsman R. , Alves D.R. , Axelrod T. , Becker A. , Bennett D. , Drake A. , Freeman K. , Geha M. , Griest K. , Lehner M. , Marshall S. , Minniti D. , Nelson C. , Peterson B. , Popowski P. , Pratt M. , Quinn P. , Rodgers A. , Stubbs C. , Sutherland W. , Vandehei T. ,   The MACHO Collaboration
Published: July 2016

We present the preliminary results of a frequency analysis of 1457 fundamental mode RR Lyrae (RR0) stars in the Large Magellanic Cloud (LMC) from MACHO Project photometry. We find the same classes of pulsational behavior as were found in our earlier survey of first overtone RR Lyrae (RR1) stars. Variables whose prewhitened power spectra contain one or two peaks close to the main frequency component in the original power spectra are commonly known as Blazhko-type variables. The present analysis shows the overall frequency of Blazhko-type stars in the total RR0 population analysed to date to be ≈ 10%. This is lower than the often cited Galactic field/globular rate of 20-30% (Szeidl, 1988).

The incidence rate of Blazhko-type variability in the LMC appears to be about three times higher in RR0 stars than in RR1 stars. This puts important constraints on possible models of the Blazhko effect.
Non-Linear Radial Pulsations Driven by Strange Modes in High-Luminosity Helium Stars
Authors: Rodríguez P. Montañés , Jeffery C.S.
Published: July 2016

We report new non-linear pulsation models for low-mass high-luminosity helium stars. These are compared with the observed periods of radially pulsating extreme helium stars.
Changes in Solar Oscillation Frequencies during the Current Activity Maximum: Analysis and Interpretation
Authors: Dziembowski W.A. , Goode P.R.
Published: July 2016

We describe systematic changes in the centroid frequencies and the splitting coefficients as found using data from MDI on board SOHO, covering cycle 23. The data allow us to construct a seismic map of the evolving solar activity - covering all latitudes. At lower latitudes, the temporal evolution closely tracks that of butterfly diagram. The additional information from higher latitudes in the map is of a significant activity in the polar region, peaking at activity minimum in 1996. The most plausible source of solar oscillation frequency changes over the solar cycle is the evolution of the radial component of the small-scale magnetic field. The amplitude of the required mean field changes is ∼ 100 G at the photosphere, and increasing going inward.
Influence of a Uniform Coronal Magnetic Field on Solar p Modes: Coupling to Slow Resonant MHD Waves
Authors: Vanlommel P. , Debosscher A. , Andries J. , Goossens M.
Published: July 2016

The influence of a constant coronal magnetic field on solar global oscillations is investigated for a simple planar equilibrium model. The model consists of an atmosphere with a constant horizontal magnetic field on top of a unmagnetized solar interior. The focus is on the possible resonant coupling of global solar oscillation modes to local slow continuum modes of the atmosphere and the consequent damping of the global oscillations.
Pulsating Red Giants: New Results
Authors: Percy J.R. , Bakos A.G. , Dunlop H. , Hussain A. , Kassim L. , Kastrukoff R. , Nyssa Z. , Wilson J.B. , Henry G.W.
Published: July 2016

We have (1) accumulated long-term (up to 15 years) photoelectric photometry of 76 bright pulsating red giants (PRGs) and related stars, with V amplitudes of 0.04 to ≥ 1 magnitude; (2) used a variety of techniques, including autocorrelation, to determine both “short” radial pulsation periods, and long secondary periods; (3) determined pulsation modes using the Q-value method; the modes range from fundamental to second overtone, independent of temperature; (4) tested wavelet analysis on small-amplitude PRGs; (5) made a special study of PRGs with amplitudes less than 0.1 magnitude; and (6) called further attention to the problem of the long secondary periods of these stars. Our studies provide a “model” for the analysis and interpretation of larger, fainter surveys such as MACHO and OGLE.
FCAPT Observations of Late B and Early A Supergiants and AGB S Stars
Authors: Adelman Saul J.
Published: July 2016

I discuss single-channel differential observations of late B and early A supergiants and AGB S stars obtained with the Four College Automated Photoelectric Telescope. The suggestion of periods longer than several years often seen in the seasonal mean magnitudes of both kinds of stars requires confirmation. I used Program Period98 to derive the most important frequencies for Deneb and for three AGB S stars.
From Planetary Nebulae to White Dwarfs: Constraints from the Asteroseismology of the Pulsating Planetary Nebula Central Star RXJ 2117+3412
Authors: Moskalik P. , Vauclair G.
Published: July 2016

We summarize the results of an asteroseismological study of the pulsating planetary nebula central star RXJ 2117+3412.
A Flower on a WIRE: Asteroseismology of a Massive Star
Authors: Cuypers J. , Aerts C. , Buzasi D. , Catanzarite J. , Conrow T. , Laher R.
Published: July 2016

Recently it became clear from a line profile study that the β Cephei star β Crucis (Mimosa) is multiperiodic with at least three modes excited. Observations of this star by the star tracker of the WIRE satellite have now confirmed the multiperiodicity in the light variations. A total of 5 million observations covering 17 days was analysed and the three main periods are in perfect agreement with the line profile results. The amplitudes are small (3, 2.7 and 0.6 millimag for the dominant modes), but this is not surprising in view of the mode identifications derived from the line profiles. More periods could still be present, including the one earlier suggested by the radial velocity data.
The MONS/Rømer Experiment
Authors: Kjeldsen H.
Published: July 2016

The aim of the MONS (Measuring Oscillations in Nearby Stars) project is to use observations of stellar oscillations to perform an asteroseismic analysis of stellar interiors. We expect to obtain high precision oscillation measurements on a sample of 20 bright stars as well as oscillation data at a slightly lower level of precision, but on a larger sample of bright stars. MONS will be launched on the Danish Rømer satellite in mid 2005.
Microscopic Physics in the Solar Standard Model
Authors: Lopes Ilidio , Turck-Chieze Sylvaine
Published: July 2016

The microphysics of the solar standard model is revised. We discuss the contribution of composition, nuclear reaction rates, screening effect and opacity (OPAL project) to the theoretical predictions on neutrino flux and acoustic modes.
Seismological Constraints on Convective Penetration in the Sun
Authors: Berthomieu G. , Morel P. , Provost J. , Zahn J.-P.
Published: July 2016

Penetrative convection is expected below stellar convection sones, where it should achieve a nearly adiabatic stratification. A theoretical prediction of the penetration depth has been recently made by Zahn (1991) which includes an arbitrary parameter ζ depending on the properties of the convective motions. We use the helioseismological constraints to calibrate the value of this parameter.
Beryllium and Lithium Abundances in Stars with a Range of Metallicities
Authors: Lopez Ramon J. Garcia , Martin Eduardo L. , Rebolo Rafael , Beckman John E. , Mckeith Conal D. , Webb John K. , Pavlenko Yakov V.
Published: July 2016

We present new beryllium abundances for three unevolved stars with [Fe/H] in the range −0.4 to −1.6. The Be II doublet is detected in the three stars. A spectral synthesis analysis has been conducted to derive the abundances. We briefly discuss their Be and Li abundances, together with a wide sample of stars from the literature, in the context of mixing processes below the convection zone.
The Abundances of Vega from the Ultraviolet Spectrum
Authors: Castelli Fiorella
Published: July 2016

We derived preliminary abundances from the ultraviolet spectrum of Vega by comparing high-resolution Copernicus spectra with spectra computed with the ATLAS9 code and with updated line lists. The Teff=9400 K, log g=3.90 model, which fits the visual flux and the Balmer profiles is able to fit the ultraviolet flux either with [M/H]=−l and microturbulent velocity ξ= 2 km s−1 or with [M/H]=−0.5 and ξ=0 km s−1. The line spectrum is fitted by ξ=2 ± 0.5 km s−1 and by an iron abundance log (N(Fe)/Ntot)=−5.2 ±0.1 dex. All the observed elements indicate underabundances ranging from about −0.35 dex (C ) up to about −1 dex (Ni, Zn). The origin of the underabundances is an open question.
Radiative Opacities
Authors: Seaton M.J.
Published: July 2016

A review is given of opacity calculations made during the past decade.
Turbulence in Stellar Interiors
Authors: Zahn Jean-Paul
Published: July 2016

This review focusses on the most recent work which has been achieved concerning turbulence in stellar interiors. Among all possible causes for such turbulence, the most powerful is certainly the convective instability in unstably stratified regions, but little was known until now beyond the fact that thermal convection is capable of establishing an almost adiabatic stratification. The latest numerical simulations (Stein & Nordlund 1989; Cataneo et al. 1991) show that turbulent convection is highly intermittent, with strong downdrafts carrying most of the energy flux.

These plumes penetrate in the stable region below, which they render nearly adiabatic over some distance (Zahn 1991); the penetration depth should be measured soon through acoustic sounding of the Sun (Berthomieu et al. 1992). Such plumes are likely to exist also in a convective core, and to penetrate into the radiative region above (Roxburgh 1989).
A Diffusion Mass-Loss Model for the Ap Star 53 Cam
Authors: Babel J.
Published: July 2016

The mechanism and properties of mass loss are poorly known for Ap stars. Present upper limits on the mass loss rate are of 10−10 M⊙yr−1, a value which does not permit any element separation. Abundance maps could be a very powerful tool to constrain the mass loss rate and the wind geometry of Ap stars, as surface abundances are sensitive to rates as small as 10−15 M⊙yr−1. We here propose a diffusion-mass loss model for 53 Cam and compute abundance distributions in the photosphere of 53 Cam. The mass loss geometry is determined from the Ca II K line profile and its time variation. We obtain that the diffusion-mass loss model explains many spectral features of 53 Cam, both in the UV and visible domains.
New Constraints on the Rotation-Induced Mixing in Stars, from Lithium Observations in Main Sequence F-Type Stars and Subglants
Authors: Charbonnel Corinne , Vauclair Sylvie
Published: July 2016

Observations of lithium in F type main sequence stars and subgiants lead to specific constraints on the rotation-induced mixing. The fact that lithium is smoothly depleted in subgiants down to factors as large as 1000 at the end of the sequence can be explained if lithium suffered extra depletion inside the star while it was on the main sequence. We propose a simple consistent model, based on the discussion of rotation-induced mixing developed by Chaboyer and Zahn (1992), which could account for these observations, as well as the observations of lithium on the main sequence.
Local and Non-Local Contributions to Horizontal Motions in Stellar Convective Zones
Authors: Petrovay K.
Published: July 2016

A method to determine the r.m.s. horizontal velocities in stellar convective zones (assuming that non-locality effects are not too strong) is given and applied to the solar case. The results may serve as useful input parameters for both convection theory and dynamo theory.
Apsidal Motion Test: Confrontation Between Theory and Observations
Authors: Claret A. , Gimenez A.
Published: July 2016

The apsidal motion test in eclipsing binaries is one of the few observational procedures available to study the stellar interior. A careful analysis of empirical data and theoretical models has been performed since more than ten years ago by our group, and in the present communication we show the most recent results obtained from the confrontation between theory and observations.

We have carried out an extensive comparison between new stellar models (Claret & Giménez 1992) making use of the latest opacity library by Rogers & Iglesias (1992) and the best available data from double-lined eclipsing binaries (Andersen, 1991). The level at which we can theoretically reproduce the observations of classical absolute dimensions, namely, R and Teff for a given mass, is shown in Figure 1, while Figure 2 shows the fulfillment of the requirements of a common age for the two components of the same system. A very similar good agreement is obtained when we take into account a moderate amount of convective core overshooting. Small differences can be easily explained in terms of metal abundance variations with respect to the adopted average value Z = 0.02. A more detailed check is shown in Figure 3 for some selected systems.
Peculiar Intrinsic Parameters of Massive Stars as a Result of an Early Phase of Homogeneous Evolution
Authors: Simon K.P.
Published: July 2016

Rotationallly induced mixing can explain several observational peculiarities of massive stars. Homogeneous evolution of differentially rotating stars including spindown due to stellar winds is studied by means of homology transformations of ZAMS models.
Rosat WFC EUV Observations of Ab Dor (And other Local Group Stars)
Authors: Kellett Barry J. , Bromage Gordon E.
Published: July 2016

The Rosat Observatory was launched on June 1st, 1990, and after a brief Performance Verification phase, performed an almost complete sky survey. One of the two main telescopes on the Observatory is the UK Wide Field Camera (WFC). The WFC is the first extreme ultraviolet (EUV) instrument to survey the whole sky, and during the survey detected several hundred active late-type stars.

The WFC (Wells et al., 1990) was built by a consortium of five UK institutes, four Universities and the Rutherford Appleton Laboratory. During the all-sky survey, two filters were used. These allow broad-band photometry to be performed. The SIA filter (lexan/carbon/boron) and S2A filter (lexan/beryllium) were alternated on a one day basis. The SIA filter covers the energy range 0.085-0.180 KeV, centred on 0.124 KeV, while the softer S2A filter covers the range 0.070-0.110 KeV (centred on 0.090 KeV) (10% efficiency) [see Kent et al. (1990) for a full description of the WFC filters].
Low-Level Stellar Variability
Authors: Grenon M.
Published: July 2016

The capability of ground-based photometry to detect and monitor low-level stellar variations is discussed in the particular case of amplitudes in the range of few magnitudes to few percent. The technical and atmospherical constraints are briefly recalled. The variability level of the so-called constant stars is discussed as function of the spectral type, the luminosity class and the effective temperature. The photometric aspects of the Hipparcos mission are presented here since this satellite allows a systematic detection of microvariables and the obtention of light curves across the whole HR-diagram with an unprecedented efficiency.
Radial and Nonradial Mode Instability in B-Type Stars
Authors: Dziembowski W.A. , Pamyatnykh A.A.
Published: July 2016

Recently three independent groups(Cox et al. 1992; Kiriakidis et al. 1992; Moskalik and Dziembowski, 1992), using opacity tables published by Iglesias and Rogers (1991), demonstrated that β Cep star models are pulsationally unstable. The instability is driven by the classical к- mechanism acting in the layer with temperatures near 2 × 105K where there is a bump in metal opacity. The groups reported results of calculations made for rather narrow ranges of stellar parameters and oscillation modes. We conducted an extensive search for unstable modes in complete evolutionary models of B-type stars of luminosity classes III - V. Our aim was to determine the domain of instability and examine its role not only in β Cep stars but also in variable stars located in the nearby areas of the H-R diagram.

An unexpected new aspect of our calculations is the use of the improved opacity data. In a very recent work Iglesias, Rogers and Wilson (1992) showed that effects of spin-orbit interactions significantly enhance opacity in the critical region for driving the pulsations in β Cep stars. These effects and improved information about the solar metal mixture have been included in the updated opacity tables kindly provided to us via electronic mail by Dr. Rogers. The consequences of this change in opacity for stability of B-type star models are indeed quite important. Contrary to previously announced results, that only the fundamental mode is unstable, we now find the first two radial overtones to be unstable, as well. Thus, the discrepancy between the theoretical prediction and the mode identification suggested by observers has been removed. Furthermore, no longer is a high metal abundance (Z > 0.03) required to explain the occurrence of pulsation in most of the objects. In fact, the theoretical instability domain in the H-R diagram, based on the models calculated with Z = 0.02, agrees better with the observational β Cep domain than that based on the models Z = 0.03.
Stephi: A New Approach to δ Scuti Asteroseismology
Authors: Belmonte J.A. , Cortés T. Roca , Vidal I. , Schmider F.X. , Michel E. , Baglin A. , Chevreton M. , Auvergne M. , Man-Geney A. , Goupil M.J. , Massacrier G. , Serre T. , Álvarez M. , Jiang S.Y. , Liu Y.Y. , Fu J.N. , Dolez N. , Sareyan J.P. , Valtier J.C.
Published: July 2016

The STEPHI network (STEllar PHotometry International) is a multinational cooperation stablished in order to get as perfect data as possible on several δ Scuti stars, within a reasonable period of time. STEPHI is currently integrated by nearly 15 people, belonging to the first four institutions cited above. However, astronomers of other institutions have eventually contributed to the network. The idea was born in 1986 and the network has been working to full operation since August 1989. A campaign, observing one or two δ Scuties is normally undertaken every 15 months. They are usually order of three weeks long, avoiding full-moon periods. Up to now, four campaigns have been performed, the last ending February 1992.

Very good outcomes on five δScuties [63 Herculis in June 1987 (Belmonte et al, 1991), GX Pegasi in September 1989 (Michel et al, 1992a), v650 Tauri in November 1990 (Belmonte and Michel, 1991; Michel et al, 1992b) and, finally, BN Cancri and BU Cancri in February 1992] have been obtained. Indeed, some very useful aditional information on comparison stars (see e.g. Belmonte et al, 1990) and sky conditions (transparency, brightness, scintillation, etc..) has been obtained as well. Aditionally, some key information about mostly all multiperiodic (four or more periods) δ Scuti stars studied up to March 1992, with good quality data, is presented in this report.
The Berkeley-Illinois-Maryland-Association Millimeter Array
Authors: Welch Wm. J.
Published: July 2016

This is a general description of the BIMA millimeter wavelength array, including some recent scientific results, the status of the expansion to a larger number of antennas, and preliminary results of attempts to correct for atmospheric “seeing”. The examples of scientific results show CO images of the galaxy IC 342, emission in other spectral lines from the two regions of massive star formation SGR B2 and Orion South, and continuum emission from solar flares and the planet Mercury. There follows a brief description of the new antennas, new correlator, new receivers, and new refrigerators of the expanded array. Finally, there is a discussion of the first results from attempts to use measured fluctuations in the brightness of the atmosphere at the observing wavelength to infer the visibility phase fluctuatons due to the atmosphere. Removal of the phase fluctuations using the brightness fluctuations provides a better image of a test observation of M87.
The IRAM Interferometer on Plateau de Bure
Authors: Guilloteau S.
Published: July 2016

In November 1992, the IRAM interferometer on Plateau de Bure has reach two years of operation. After a review of its current technical status, with emphasis on its specificities, this paper presents an overview of its capabilities, illustrated by examples taken from the scientific program carried on during these two years. On-going upgrades and future plans are presented.
A VLBI Study of H2O Maser Spots Associated with a Molecular Outflow ρ Oph-East
Authors: Iwata Takahiro , Takaba Hiroshi , Matsumoto Kin-Ya , Kameno Seiji , Kawaguchi Noriyuki
Published: July 2016

A molecular outflow is one of the most conspicuous active phenomena associated with protostars, and the kinetic energy of its outflowing mass is as large as that of random motions of ambient molecular cloud, which suggests that outflow has dynamically influence on ambient molecular gas. Possible observational evidence which suggests the existence of dynamical interaction between molecular outflow and ambient molecular cloud has been detected in several star forming regions (Fukui et al. 1986; Iwata et al. 1988). Recent detections of H2O maser emission associated with low-mass protostars (e.g. Comoretto et al. 1990) also suggest that there still exist active phenomena in the low-mass star forming regions.

Molecular outflow ρ Oph-East, discovered toward a low-mass protostar IRAS 16293-2422 (Fukui et al. 1986), has been known as a site of dynamical interaction between molecular outflowing gas and ambient molecular cloud by CO and NH3 observation (Mizuno et al. 1990). Existence of several strong H2O maser spots (Wilking & Claussen 1987; Wotten 1989; Terebey et al. 1992) also suggests that active phenomena are occurring in this region. In this paper, we report our result of H2O maser observation for molecular outflow ρ Oph-East with milli-arcsecond resolution by VLBI.
The Submillimeter Telescope - A Status Report
Authors: Martin R. N. , Baars J. W. M.
Published: July 2016

The Max-Planck-Institut für Radioastronomie, Bonn and the Steward Observatory of the University of Arizona, Tucson are collaborating on the construction and operation of a dedicated submillimeter facility. The Submillimeter Telescope (SMT) is a 10 m diameter reflector surrounded by a corotating enclosure. The instrument is an alt-azimuth mounted f/13.8 Cassegrain homology telescope with two Nasmyth and bent Cassegrain foci. The SMT will have diffraction limited performance at a wavelength of 300 μm. and an operating overall figure accuracy of 15 μm rms. The primary and secondary reflector surfaces are constructed out of aluminum-core, carbon-fiber-reinforced-plastic (CFRP) face sheet sandwich panels. The primary reflector backup structure and secondary support are fabricated from CFRP structural members. This modern technology provides both the means for reaching the required precision of the SMT for both night and day operation (basically because of the low coefficient of thermal expansion and high strength-to-weight ratio of CFRP) and a potential route for the realization of lightweight telescopes of even greater accuracy in the future. The SMT will be the highest accuracy radio telescope ever built.

The SMT is located at an altitude of 3180 m on Emerald Peak (Mt. Graham) 120 km northeast of Tucson in southern Arizona. Measurements indicate that atmospheric conditions allow submillimeter observations during about 40% of the time in winter months. The telescope is placed in a co-rotating enclosure of novel design. The enclosure fits tightly around the telescope, with the focus flanges extending from the elevation bearings into the receiver rooms of the enclosure. A flat tertiary mirror is used to direct the beam through either of the two elevation bearings. Thus, we are able to mount receivers directly on the telescope while maintaining laboratory type conditions in the access area surrounding the receivers. On the “facility instrument” side, several receivers can be operated simultaneously.
The Fiber Optic Link and Delay System at OVRO
Authors: Soares Schubert F. , Padin Stephen
Published: July 2016

The design and performance details for a link, and a tracking delay system operating in the 0.5 to 4 GHz band are presented. This is a composite fiber optical and microwave system, with delay bits ranging from 512 to ns in binary steps.
Statistical Comparison of CLEAN and MEM
Authors: Ishiguro M. , Ishiguro M. , Morita K.-I. , Murata Y.
Published: July 2016

Assume that a set of visibility data

{(uj, vj, zj)| j = 1, 2,...,N}

is given where visibility zj observed at time j can be expressed in terms of “true visibility” defined by the brightness distribution T(x,y) and observation noise εj:

where{(uj, vj)} is a given set of points in the u-v plane. It is assumed that u-v plane is gridded with the interval Δ. The dirty map obtained by

is a crude estimate of the true brightness distribution. CLEAN and MEM are two typical methods to get better estimates.
Spectral Turn-Over of Radio Arc Filaments at 43 GHz: Magnetic Tubes of 4000-yr Old in the Galactic Center
Authors: Sofue Yoshiaki , Murata Yasuhiro , Reich Wolfgang
Published: July 2016

The origin of the straight magnetic filaments in the Radio Arc near the Galactic Center is still controversial: either if they are permanent structure of constant configuration for a galactic-time scale, or they are temporary structure of short life time such as due to a sudden injection of cosmic rays or to sudden shock compression. Measurement of life time of the radio emitting cosmic ray electrons consisting the filaments is one of the crucial methods besides a time variation measurement of the fine structure of the filaments.

In order to investigate possible spatial variation of spectral index at higher frequencies in the filaments, which might give information about the life time of cosmic ray electrons, we have performed high-resolution radio continuum observations at 43 GHz of the GO.18-0.04 region of the radio Arc near the galactic center using the Nobeyama Millimeter-wave Array. A detailed description of this work is given in Sofue et al. (1992).
Aperture Synthesis Obervations of The Galactic Center 50-km·s−1 Moleculer Could
Authors: Tsuboi Masato , Okumura Sachiko K. , Ishiguro Masato
Published: July 2016

Molecular clouds in the Galactic center region are distributed mainly along the Galactic plane and have filamentary shapes with several clumps (Bally et al. 1987, Tsuboi et al. 1989). The “50-km.s−1 molecular cloud (M-0.02-0.07)”, which is located ~3’ east from Sgr A West, is one of most remarkable clumps on these molecular filaments. The intimate relation between this cloud and Sgr A East has been mentioned by many authers (e.g. Ho et al. 1986). Several compact HII regions are located toward the cloud (Ekers et al. 1983). The recombination line velocities correspond to the molecular line velocities in the cloud (Goss et al. 1987). Thus this cloud is one of active star forming regions near the Galactic center.

We observed the 50-km-s−1 molecular cloud in CS J=1-0 emission line (48.991 GHz) using the Nobeyama Millimeter Array (NMA) to reveal the detailed structure of the star forming regions near the Galactic center.
Observations of Orion Molecular Cloud with NMA
Authors: Murata Y. , Kawabe R. , Ishiguro M. , Morita K.-I. , Hasegawa T. , Hayashi M.
Published: July 2016

We have made aperture synthesis multifield observations of Orion Molecular Cloud-1 (OMC-1) in the CS (J=1-0) line using the Nobeyama Millimeter Array (NMA), and obtained 9” resolution maps over 10’ length. The OMC-1 ridge shows a wiggled structure. The position angle of whole the ridge is ~ 0° - 10°, but ~ 20° - 30°around the clumps. It is possible to make this structure by the magnetic field with a position angle of ~ 150°. We also found filamentary structures in the northwest of Orion-KL, with a length-width ratio of more than 25, which are made by the gas flow from Orion-KL.
Probing Molecular Shocks with Millimeter and Near-IR Interferometric Imaging
Authors: Wang Zhong , Burton Michael G.
Published: July 2016

We make detailed comparison between the high resolution CO (J=2-l, 1-0) maps obtained with the OVRO Millimeter Array and the 2.12 µm H2(v=1-0) S(1) multi-channel images obtained using a Fabry-Perot system with the UKIRT Infrared Array Camera. Both datasets cover an interstellar shockfront region in the vicinity of the Galactic supernova remnant IC 443, and provide complementary information of the strongly shocked molecular gas on scales of 0.01 pc and a few km s−1. Combining our data with other atomic/molecular line probes, we find that a combination of bow-shock and cloud internal shock can best describe the interface between the supernova blast wave and pre-existing molecular clouds.
NMA Observations of HH83
Authors: Nakano Makoto , Sugitani Koji , Sato Fumio , Ogura Katsuo
Published: July 2016

We have reported NMA observations of HH83 with CS (J=2-l) line. The interacton between the outflow and the molecluar cloud is found.
Numerical Simulations of Collapse of a Magnetized Rotating Molecular Cloud
Authors: Ohta Kanji , Habe Asao
Published: July 2016

Recent observations reveal the velocity structure of star forming regions and the magnetic field in molecular clouds. It is known from observations that the molecular clouds rotate. It is suggested that the magnetic field have a important roll of the star formation process (e.g. Myers and Goodman 1988) and rotation of cloud have effects for evolution of molecular cloud. However it is not cleared how the magnetic field plays a roll of the star formation process in a rotating cloud.

In the previous theoretical studies, most of simulations are performed for collapse process of a rotating cloud without magnetic field (e.g. Miyama et al. 1984, Boss 1990) or collapse process of a magnetized cloud without rotation (e.g. Scott and Black 1980). Dorfi (1982) studied collapse of a magnetized, rotating cloud. However he did not calculate those with high resolutions, since he performed 3-dimensional calculations of about 6000 grid points.

Since observation instruments have been developed, it is possible to observe the star forming regions with good resolution. We study the collapse of the rotating, magnetized, isothermal cloud by mean of the axisymmetric numerical simulations with high resolution.
CO (2-1) in IC 342
Authors: Turner Jean L. , Hudson David , Hurt Robert L.
Published: July 2016

We present aperture synthesis maps of the CO J=2-1 emission in the central region of the spiral galaxy IC 342. The 4” resolution maps reveal emission that is a factor of two brighter than the CO (1-0) emission mapped at the same resolution. Since the CO (2-1) emission is likely to be optically thick, the high ratio is probably due to the fact that the two transitions sample different cloud layers in externally heated clouds. The high signal to noise of the maps indicates that CO (2-1) will be a powerful tool in the study of gas in galaxies.
The Polar Ring Starburst Galaxy NGC 660
Authors: van Driel W. , Combes F. , Nakai N. , Yoshida S.
Published: July 2016

NGC 660 is a gas-rich, peculiar polar ring RSBa-type starburst galaxy with two distinct morphological and kinematic components: an inner disc, seen almost edge-on, with a major axis position angle of 45° and a diameter of ~11 kpc [D=13 Mpc, Ho=75 kms−1 Mpc−1], and an outer polar ring (p.a. 170°) with a diameter of 31 kpc, inclined on average about 55° with respect to the major axis of the inner disc.

We obtained deep, 30 min. exposure CCD images of NGC 660 with the 105 cm Schmidt telescope of Kiso Observatory in the B, V, R, and I bands. A preliminary reduction shows that the inner disc is clearly redder than the polar ring and the nucleus.

Optical spectra indicate that the galaxy has a LINER-type spectrum, suggesting intense massive star formation in the nucleus. We obtained a long-slit Ha spectrum along the major axis of the inner disc at ESO, which shows a very steep gradient near the nucleus. Assuming an inclination of 80°, it implies a rotational velocity of about 150 km s−1 for the inner disc.
A Basic Step Toward the CO-Line Tully-Fisher Relation
Authors: Sofue Yoshiaki , Schöniger Franz
Published: July 2016

The Tully-Fisher relation makes use of the correlation between the HI linewidth and the luminosity of a galaxy and is one of the most powerful tools to estimate distances of galaxies. Because of the smaller beam the CO line might be an alternative to HI for distant galaxies which so far can not be examined even by the largest telescopes (Dickey and Kazes 1992).

In order to consider the question whether the CO lineprofile could be used as an alternative or a supplement for HI in the Tullly-Fisher relation, we compared the total CO (J=2-1) line profiles of ten galaxies with the corresponding HI profiles. Four almost perfect edge-on galaxies (NGC 891, NGC 4565, NGC 4631 and NGC 3079) and the Seyfert galaxy NGC 1808 have been observed in CO using the Nobeyama 45-m telescope. The HI profiles and the data of the other galaxies has been taken from the literature.
12CO(J = 1-0) Mapping of the Merging Galaxy NGC 3310
Authors: Kikumoto T. , Taniguchi Y. , Suzuki M. , Tomisaka K.
Published: July 2016

Since molecular gas clouds in nuclear regions play important roles on both the intense star formation and fueling active galactic nuclei, a large number of molecular-line observations have been made for starburst, Seyfert, and merging galaxies. Recently, millimeter-wave arrays have been used to study circumnuclear molecular gas in merging galaxies. Most of them, however, have been devoted to the observations of more luminous objects such as ultra-luminous merging galaxies (ULMGs) discovered by IRAS (Sanders et al. 1988). In order to obtain a comprehensive understanding, it is necessary to study less-luminous merging galaxies. With this motivation, we present results of CO mapping of NGC 3310 which is one of less luminous merger candidates (LFIR = 2.5 × 1010Lʘ).

The central region (5.1 kpc in diameter) of NGC 3310 was observed in CO(J = 1 − 0) using the Nobeyama Millimeter Array. The synthesized beam size was 6″.3 × 6″.1, which corresponds to 500 × 480 pc at the distance 16.3 Mpc. Our main results and conclusions are summarized as follows.
CO(3-2) Observations of IRAS F10214+4724 at NMA
Authors: Kazushi Sakamoto , Ryohei Kawabe , Sumio Ishizuki , Masato Ishiguro
Published: July 2016

We have observed CO(J=3-2) emission of the z=2.286 galaxy IRAS F10214+4724 using the Nobeyama Millimeter Array.
N and Fe-Peak Elemental Abundances from IUE Co-Added Spectra of Hg-Mn and Normal Stars
Authors: Roby Scott W. , Adelman Saul J. , Leckrone David S. , Cowley Charles , Wahlgren Glenn M.
Published: July 2016

Leckrone and Adelman have established an IUE observing strategy that has yielded co-added spectra with enhanced S/N ratios for several A and B stars. New observations by Roby and Adelman using the same technique have added two new Hg-Mn stars into this sample. We have begun a long-term study of elemental abundances in this uniform, high-quality set of IUE spectra for 13 stars. We report on the first stages of this project: abundances for N, Cr, Mn, Fe, Co, and Ni. The study of the Fe- peak elements show that our data set can provide accurate abundances and that abundances obtained from UV and optical spectra often are in good agreement. This study provides the groundwork for self-consistent abundance analyses of more exotic elements in our long term project.
Estimation of Stellar Magnetic Fields from Line-Strengths: Refined Hensberge-De Loore Method
Authors: Takeda Yoichi
Published: July 2016

A method for determining the strength of a stellar magnetic field is presented, which is based on the requirement that the scatter of abundances from various lines should be minimized on the best choice of the field strength and the microturbulence. This procedure is applied to o Peg and cool Ap stars, showing that the resulting solutions are consistent with those derived from other methods.
Radio and X-Ray Emissions from Chemically Peculiar B- and A-Type Stars: Observations and a Model
Authors: Linsky Jeffrey L.
Published: July 2016

Conventional wisdom holds that early-type and late-type stars have very different outer atmospheres, because the early-type stars lack deep convective zones. I argue that the magnetic chemically peculiar (CP) stars hotter than about spectral type A2 display many of the activity phenomena seen in the most active late-type stars. In particular, many CP stars are luminous nonthermal radio and coronal x-ray sources like the RS CVn systems. A wind-fed magnetosphere model has been proposed to explain both the nonthermal radio and the x-ray emission. In this model the stellar wind plays the role of a mechanical energy source analogous to the role played by convection in the active late-type stars.
Statistics of CP Stars in a Magnitude-Limited Sample: The Bright Star Catalogue
Authors: Schneider H.
Published: July 2016

In the past several authors investigated the incidence of CP Stars among field stars of the upper main sequence, e.g. Jaschek&Jascheck (1967), Wolff (1968), Abt (1979), or in open clusters e.g. Young&Martin (1973), Hartoog (1976), North&Cramer (1981). But the published values seem not to be very precise or universal because of the use of incomplete data bases like Osawa’s list (1965) or the old version of the Bright Star Catalogue or the concentration on selected samples e.g. open clusters. Only Smith (1973) gave realistic values in the case of CP1 stars.

In the meantime two decades passed and many new observations were obtained. In 1982 a new version of the Bright Star Catalogue with better spectral classifications was issued and a supplement to the BS catalogue was published (1983). Furthermore, Renson and co-workers presented 1991 their General Catalogue of Am and Ap Stars (in the following abbreviated to GCAAS). Now the moment has come to establish new and hopefully more precise values of the incidence of CP Stars using the new version of the Bright Star Catalogue and its supplement as the data base.
Molecular Opacities in Cool Dwarf Stars
Authors: Liebert James
Published: July 2016

The term dwarf stars identifies objects of small radius in the Hertzsprung-Russell (H-R) Diagram, but encompasses more than one phase of stellar evolution. The M dwarfs (type dM) populate the main sequence at the low mass end; these are the coolest core hydrogen-burning stars. They belong generally to the Galactic disk, or Population I, have relatively small space motions with respect to the Sun, and have similar metallicities to the Sun (although perhaps only within a factor of several). In particular, this means that the abundance of oxygen is always greater than that of carbon. The M subdwarfs (sdM) are the Population II counterparts, showing low metallicities and high space motions. Because they have smaller radii, they define a main sequence at lower luminosity than the M dwarfs for a given temperature. Hence the term subdwarf.
Dissociation Energies and Partition Functions of Small Molecules
Authors: Costes Michel , Naulin Christian
Published: July 2016

For a simple dissociation equilibrium

the equilibrium constantKpat temperatureTcan be written in terms of partial pressurespor densitiesnin the form given by Equation 6 of Tatum (1966)

wheremis the reduced mass of AB,kthe Boltzmann constant,hthe Planck constant,QA,QB,QABthe internal partition functions of the species, andD0the dissociation energy of AB. This equation derives from a more general expression ofKp(T) for a chemical reaction that is demonstrated in all physicalchemistry textbooks treating statistical thermodynamics (see for example Atkins 1990). Partition functions are weighted Boltzmann factors

with ϵncorresponding to the energy of the eigenstates of degeneracygn. Provided all the eigenvalues are known,Qvalues can be calculated exactly. Derivations and calculations of the partition functions can be found in textbooks or in reviews relating to astrophysics.
Computation of Opacities for Diatomic Molecules
Authors: Kurucz Robert L.
Published: July 2016

In this section I briefly describe my efforts to improve the atomic and molecular line data. This work is described in more detail in Kurucz (1992a). In subsequent sections I briefly describe three methods for computing opacity and the models and spectra that result from using them.

My model calculations in the 1970s used the distribution-function line opacity computed by Kurucz (1979a,b) from the line data of Kurucz & Peytremann (1975). We had computedgfvalues for 1.7 million atomic lines for sequences up through nickel using scaled-Thomas-Fermi-Dirac wavefunctions and eigenvectors determined from least squares Slater parameter fits to the observed energy levels. We also collected all published data ong fvalues and included them in the line list whenever they appeared to be more reliable than the computed data (that work is ongoing, but I am running behind).
The MORBID Method
Authors: Jensen Per
Published: July 2016

The present communication is concerned with the problem of calculating the rotation-vibration energies and the absorption intensities of a triatomic molecule from the effective nuclear potential energy function and the dipole moment surfaces within the Born-Oppenheimer approximation (Born & Oppenheimer 1927). There are at least two astrophysical applications of such calculations:

— Detailed spectra of triatomic molecules can be computed under the conditions prevailing in stellar atmospheres and compared with observed spectra.

— Such spectra can also be used for constructing a wavenumber-dependent absorption coefficient which can be employed for opacity calculations as outlined, for example, by Jørgensen & Jensen (1993).
The Use of CCDs on Schmidt Telescopes
Authors: Armandroff Taft E.
Published: July 2016

The implementation of CCDs on Schmidt telescopes is discussed, including the capabilities of such systems and the new types of observations that they facilitate. An analysis of the demand for and use of the CCD system on the Burrell Schmidt is presented. Some examples of scientific investigations accomplished with Schmidt CCD systems are given. The future evolution of CCD capabilities on Schmidt telescopes is discussed.
Sky Surveys and Atlases from the Large Schmidt Telescopes
Authors: Morgan D. H.
Published: July 2016

This paper describes the major sky surveys carried out with the large Schmidt telescopes and the sky atlases made from them. It also describes some of the science which has come from them and notes the importance of this work in almost every branch of astronomy.
A Southern Sky Survey of Low Mass Stars and Brown Dwarfs
Authors: Thackrah Andrew D. , Hawkins Michael R. S.
Published: July 2016

We are conducting a survey of the southern sky to study the properties of the lowest mass stars and the sub-stellar brown dwarf population thought to exist at masses below 0.08 M⊙. The survey makes use of plates from the UK and ESO Schmidt telescopes, using the new SuperCOSMOS plate measuring machine at Edinburgh to provide a catalogue of photographic BRI colours and proper motion measurements. Candidates are selected by extreme R–I colour (> 2.5) to a plate-limited magnitude of I ≈ 19.0 and R ≈ 21.0. The size of the survey is only limited by the progress of the UK Schmidt I band survey and the availability of photometric data for calibration of SuperCOSMOS measurements. It is anticipated that the survey will form part of a multi-colour proper motion database of southern sky objects.
Why We Need a Deep Spectral Survey of the Milky Way
Authors: Kurtanidze Omar M. , Nikolashvili Miriam G.
Published: July 2016

In this short review we briefly discuss all the extensive low dispersion objective-prism spectral surveys carried out in the last fifty years for the study of the surface and space distributions of late-type giant stars, namely C stars. In the light of data obtained and new discoveries, the expediency of undertaking a deep mI low dispersion spectral survey in the near-infrared spectral region is considered.
The Star Forming Regions of Orion
Authors: Kogure Tomokazu
Published: July 2016

The distribution of emission line stars in Orion is presented, based on our recent surveys and other previous ones. Particular attention is given for the central 10 × 10 square degrees to compare some properties of emission line stars and OB association stars. As a result, a possibility of bimodal star formation is suggested in this region.
Survey Catalogues of Kiso Ultraviolet-Excess Galaxies
Authors: Miyauchi-Isobe Nagako , Takase Bunshiro , Okamura Sadanori
Published: July 2016

Our survey for KUGs (Kiso Ultraviolet-excess Galaxies) is based on the multi-colour method applied to photographic plates taken with the Kiso Schmidt telescope. In total, 8,968 KUGs were detected on 170 plates covering some 5,100 square degrees. They are listed in 17 separate catalogues, where morphological type and UV-excess degree are given for each object together with position, size, and magnitude. After the appropriate editing of multiple entries of the same object detected on different plates, we produced a merged catalogue where 8,162 KUGs were arranged in order of right ascension. The accuracy of the position of KUGs was examined using the data of 806 KUGs whose positions were measured on different plates.
Several Possible Designs for BFOSC
Authors: Shi-Yang Jiang
Published: July 2016

Various optical solutions are presented for the Beijing Faint Object Spectrograph and Camera of Beijing Astrophysical Observatory 2.16 m telescope. They are based either on dioptric or catoptric designs including an adaptation of the existing Cassegrain spectrograph.