平成3年度（第2号）

論文リスト：

BL Lac天体とクェーサーの光学モニター観測（予備報告）、 pp1-7
　著者：尾久土正己
　所属：兵庫県立西はりま天文台公園

概要： V-band photometric monitoring of four BL Lac objects and two quasers has been in progress at Nishi-Harima Astronomical Observatory since October, 1991. Observations were carried out using a CCD camera system attached to the 0.6m reflector. Results of six months observations are presented. The BL Lac object OJ287 dimmed about one magnitude in three months between November, 1991 and February, 1992.

　キーワード：BL Lac Objects -- Quasers -- Optical variability
　電子版を入手： PDF (2.3MB)

リービット変光星の線形非断熱模型、 pp8-15
　著者：石田俊人
　所属：東北大学/兵庫県立西はりま天文台公園

概要：Bright variable supergiants S65-08 and S65-48 in the LMC and HV1956 in SMC are studied by using linear nonadiabatic radial pulsation models. Comparing observd properties with results obtained by linear models, it appear that (1) the mass adequate to S65-08 is 25 ~ 30 M◎, (2) all calculated models of S65-48 are pulsationally stable, (3) the mass adequate to HV1956 is 8 ~ 9 M◎. Futhermore, the evolutionary status and the characteristics as a classical Cepheid are examined for S65-08 and HV1956. It is found that the first crossing object of the evolutionary sequence with mass loss effect fit to the S65-08 model. On the other hand, it is found that the overluminosity of the HV1956 model as a classical Cepheid with 8 ~ 9 M◎ makes no to match to evolutionary calculations not to relations of Classical Cepheids. In conclusion, model calculations shown here indicate that (1) although the effective temperature of S65-08 is too high for a classical Cepheid, this star is still a possible member of classical Cepheids, (2) S65-48 seems not a classical Cepheid, but a yellow semiregular variable, and (3) HV1956 is probably not a classical Cepheid.

　キーワード：Classical Cepheids -- Linear Nonadiabatic Models -- Magellanic Clouds -- Stellar Pulsation
　電子版を入手： PDF (3.1MB)

惑星状星雲NGC 1501中心星の測光観測（予備報告）、 pp16-19
　著者：佐藤隆夫、尾久土正己、時政典孝、黒田武彦、石田俊人
　所属：兵庫県立西はりま天文台公園

概要： We participated in a global photometric campaign on the pulsating central star of the planetary nebula NGC 1501. Observations were carried out using a CCD on the 0.6m telescope at Nishi-Harima Astronomical Observatory. They were made in V-band during the campaign and in R-band later on. We have detected a pulsating period of 46 minutes.

　キーワード：CCD Photometry -- Variable Stars -- Pulsating Stars -- Planetary Nebulae
　電子版を入手： PDF (1.7MB)

食連星BO PEGASIの測光観測、 pp20-24
　著者：小林英之1、尾久土正己2、石田俊人2、佐藤隆夫2、定金晃三1
　所属：1) 大阪教育大学、2) 兵庫県立西はりま天文台公園

概要： CCD photometric observations of the eclipsing binary system BO Pegasi are carried out between August and November, 1991. The primary minimum occurs earlier than the prediction by about 36 minutes (O-C = -0.02522 day). Mass transfer from the primary component to the secondary is suggested.

　キーワード：Photometry -- Variable Stars -- Eclipsing Binaries
　電子版を入手： PDF (1.9MB)

バルマー不連続から求めたA型及びF型星の表面重力、 pp25-34
　著者：黒田武彦
　所属：兵庫県立西はりま天文台公園

概要： Surface gravities log g of 152 normal A and F stars have been derived by comparing observed and computed Balmer decrements. The Balmer decrements measured by the spectrophotometric data and (B-V) color indices, and effective temperatures have been calibrated to derive the surface gravities. These surface gravities agree well at (B-V) > 0.00 and/or Teff < 10000K. Mean surface gravities estimated by the two surface gravities slightly deviate from recent determinations towards low values.

　キーワード：Surface gravity -- Balmer decrement -- A and F stars
　電子版を入手： PDF (3.2MB)

動径脈動星モード間の結合計数、 pp35-40
　著者：石田 俊人
　所属：兵庫県立西はりま天文台公園

概要： Recent progress of the theory on coupling coefficients of radial stellar pulsation is briefly reviewed. In this review, two approaches to the mode coupling in pulsating stars are discussed, namely amplitude equations and oscillator model equations. Moreover, some problems in the present research of the coupling coefficient are pointed out.

　キーワード：Coupling Coefficients -- Nonlinear Oscillation -- Stellar Pulsation
　電子版を入手： PDF (2.6MB)

IUE衛星の観測を使った紫外域の星間吸収 I、 pp41-45
　著者：黒田武彦
　所属：兵庫県立西はりま天文台公園

概要： Ultraviolet interstellar extinction for four early-type main-sequence stars were derived using the IUE low-dispersion spectra. Selected pairs of reddened-unreddened stars were used. The interstellar extinction curves don't have the same shape. It indicates that the interstellar graines are different both in composition and size distribution towards different stars.

　キーワード：Interstellar extinction -- Ultraviolet spectra
　電子版を入手： PDF (1.7MB)

10cm太陽Hα像観測システム、 pp46-54
　著者：時政典孝
　所属：兵庫県立西はりま天文台公園

概要： A 10cm refractor Solar Hα observation system has been installed in October, 1991 at the Nishi-Harima Astronomical Observatory.
An optical system of the system is very simple, because it consists of only two lense systems which are Object lens and focul extended lens. A filter to observe H-Alpha image is the birefringent filter for H-Alpha line. And the H-Alpha images taken with 2/3-inch CCD camrea are recorded to a video tape and an optical disk, and digitized by an image processing board.

　キーワード：Solar Telescope -- H-Alpha observation -- image processing system
　電子版を入手： PDF (3.2MB)

ドーム内の熱環境の調査 II、 pp55-64
　著者：岡野浩平1、尾久土正己2、定金晃三1
　所属：1) 大阪教育大学、2) 兵庫県立西はりま天文台公園

概要： We are performing measurements of thermal conditions in the observing room and in the telescope tube of Nishi-Harima Astronomical Observatory since February, 1991, extending over one year. Measurements are carried out automatically using thermister devices and a personal computer system. We find that the thermal shield by the dome and the telescope tube results in a degradation of seeing except in summer. In order to overcome the degradation of image, we began air ventilation in the observing room all the day. Consequently the thermal conditions and the seeing have been obviously improved.

　キーワード：Dome -- Telescope -- Thermal condition -- Seeing
　電子版を入手： PDF (4.0MB)

パソコン版画像処理ソフト「西はりまイメージ」、 pp65-68
　著者：時政典孝
　所属：兵庫県立西はりま天文台公園

概要： I have developed the image tool, "Nishi-Harima Image", which makes it possible for everyone to treat the image data on their personal computer. For user's convenience, most of features of the tool are aveilable by using mouse device. The tool displays 20 frames simultaneously and more frames are displayed by scrolling up and down. Therefore, this tool seems to be useful for searching the object image, and for finding duplication of images. Some simple image processing features are also available in this tool.

　キーワード：Image Processing -- Personal Computer
　電子版を入手： PDF (1.4MB)

ノーモン型日時計の理論と設計、 pp69-73
　著者：北村静一
　所属：英知大学/兵庫県立西はりま天文台公園

概要： We show the sundial of gnohmon type which is very simple and useful. By appropriate mathmatical transformation, we can get a chart of loci of shadow of Gnohmon which are hyperbola or ellipse, and loci of equi-time which are straight lines. We can use this chart and gnohmon as a sundial. We show some process of transformation and program of drawing of loci.

　キーワード：Gnohmon-Sundial
　電子版を入手： PDF (1.6MB)