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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Astronomy and Space Sciences
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Journal DOI :
The Korean Space Science Society
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Volume & Issues
Volume 9, Issue 2 - Dec 1992
Volume 9, Issue 1 - Jun 1992
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SURFACE BRIGHTNESS DISTRIBUTION ON NGC 7755
Chun, Mun-Suk ; Sohn, Seong-Min ;
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 1~10
Isophote map and luminosity profile of the barred spiral galaxy NGC 7755 are obtained from PDS scanning of PAL 0-471 plate. From the isophote map, NGC 7755 can be classified SBbc(r) with asymmetric bar ring. We get several physical parameters
of NGC 7755 from the analysis of the luminosity distribution.
STRUCTURE OF THE SPIRAL GALAXY NGC 300 -1. The generalzation of Toomre's mass model-
Rhee, Myung-Hyun ; Chun, Mun-Suk ;
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 11~29
In 1963, Toomre built up classes of mass models for the highly flattened galaxies which have free parameters n,
. In order to keep the universal dimension, we adopt parameters
. Series of the normalized Toomre's mass models (G =
= 1, n = 1 to 7) are derived and the normalized parameters
are determined by the iteration method. Replacing parameters
, we can get the generalization of Toomre's mass model.
THE REFLECTION EFFECT ON THE ECLIPSING BINARY BY THE WILSON AND DEVINNEY'S MODEL AND RUSSELL AND RUSSELL AND MERRILL'S MODEL
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 30~40
The reflection effect on three types of eclipsing binaries has been analyzed based on the Wilson and Devinney's model and Russell and Merrill's model. The reflection effect was displayed on the theoretical light curves for the various conditions using the Wilson and Devinney's light curve program. Two models were compared after the rectifing the theoretical light curves including the reflection effect with the Russell and Merrill's method. The result shows that two models have an agreement on the reflection effect just in cases of the small difference in temperature adn albedo between two stars in the system.
PERIOD STUDIES OF CLOSE BINARIES, AO CAM AND AW CAM
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 41~51
Photoelectric observations of close binary stars, AO Cam and AW Cam, were made during the 1984 observing season with the 61cm reflector at the Sobaeksan Observatory. One time of primary minimum for AO Cam and three primary epochs for AW Cam were derived from the observations of these two systems. Times of minimum light of these two binaries collected from literature were analyzed with a least square fitting method. New improved light elements for AO Cam and AW Cam were determined. The orbital period of AO Cam had been constant from Octobar, 1980 (JD 244520) to February, 1985 (JD 2446107). However, one secondary time of minimum (JD 2447864.7879) of AO Cam published recently by Mullis and Faulkner(1991) shows large deviation of about 4.6 minutes (
) from the one predicted by our new light elements. Future observations of times of minima for this system are needed to test this period change. The orbital period of AW Cam has been constant as P=
for about sixty years from the early 1930's to the present.
A STUDY ON THE KOREAN IONOSPHERIC VARIABILITY
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 52~68
The ionosphere in accordance with solar activity can affect the transmission of radio waves. The effect of the ionosphere on the radio wave propagation are scattering of radio waves, attenuation, angle error, ranging error, and time delay. The present study is based on the Korean ionospheirc data obtained at the AnYang Radio Research Laboratory from January 1985 through October 1989. The data are analyzed to show the daily and the annual variations of the ionosphere. The data are also used to simulate the density distribution of the Korean ionosphere following the Chapman law.
A STUDY ON THE RADIO PROPAGATION IN THE KOREAN IONOSPHERE
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 69~88
The effects of the ionosphere on the radio wave propagation are scattering of radio waves, attenuation, angle error, ranging error, and time delay. If ionospheric conditions are suitable, the charged particles can remove energy from radio waves and thus attenuate the signal. Also, a radio wave traveling a path along which the electron density is not constant undergoes changes in direction, positon and time of propagation. The present study is based on Korean ionospheric data obtained at the AnYang Radio Research Institute from Jan. 1985 through Oct. 1989. The data are used to simulate the Korean ionosphere following the Chapman law. The effects of the model ionosphere on the radio wave propagation, such as the angle, position error, time delay, and the attenuation, are studied for the various cases of the wave frequency and the altitude.
BVRI PHOTOMETRY OF VV CEPHEI
Nha, Il-Seong ; Im, Hong-Seo ; Lee, Yong-Sam ; Jeong, Jang-Hae ;
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 89~96
UBV observations of VV Cep were made in 1988-1992 as a part of the Ten-year Observing Program for Long Period Eclipsing Binary Stars(1982-1992) at Yonsei University Observatory. In addition to these the observations in the longer passbands in R and I are also made in the 1991-1992 season at the same observatory. Atmospheric extinction coefficinets determined by a comparison star 20 Cap for B and V each night have been deduced a linear relation,
=0.159+1.066kV. In this paper, light curves of this star in BVRI passbands for the 1991-1992 season only are presented. Two periodic light variations of both long-term and short-term are found as for 90 days and 20 days, respectively.
SPECTROSCOPIC STUDY OF VV CEPHEI
Chun, Mun-Suk ; Gim, Mun-Hwan ;
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 97~110
Observed spectra of the long period eclipsing binary VV Cephei show emission features of Balmer and some ionized metal lines. These features were interpreted as the result of the extended envelope activity surrounding the secondary star. Radial velocities and equivalent widths were calculated from some metal lines.
ULTRAVIOLET SPECTROPHOTOMETRY OF VV CEPHEI
Kang, Young-Woon ;
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 111~119
The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately 30000K, based on the flux distributions during egress. Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 2350
have been analyzed by the modified Wilson and Devinney light curve program. The radii of the B star and M star were deduced to 0.05 and 0.22 of unit separation, respectively. The UV light curves show an evidence that the light was attenuated by the highly opaque atmosphere of the M star.
PHASE-DEPENDENT LINE PROFILES OF VV CEP
Journal of Astronomy and Space Sciences, volume 9, issue 1, 1992, Pages 120~125
The normalized line profiles of VV Cep have been calculated by integrating the equation of transfer. The Sobolev theory was adopted and the wind velocity distribution was assumed to be V(r) = V
. The peaks of the line profiles for the phase 0.06 and 0.80 appear at near half maximum and zero velocity surface of the wind, respectively.