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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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The Korean Space Science Society
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Volume & Issues
Volume 10, Issue 2 - Dec 1993
Volume 10, Issue 1 - Jun 1993
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SPIN-AXIS ATTITUDE DETERMINATION PROGRAM FOR THE GEOSYNCHRONOUS TRANSFER ORBIT SPAECRAFT
Lee, Byoung-Sun ; Eun, Jong-Won ;
Journal of Astronomy and Space Sciences, volume 10, issue 1, 1993, Pages 1~16
Three typer of spin-axis attitude determination program for the geosynchronous transfer orbit spacecraft are developed. Deterministic closed-from algorithm, batch least-square algorithm and stabilized Kalman filter algorithm are used for implemetation of three programs. EUROSTAR bus model from British Aerospace is used for attitude sensor modelling. Attitude determinations using three programs are performed for the simulated sensor data according to INMARSAT 2-F1 prelaunch mission analysis.
THE CHARACTERISTICS OF CAITICAL INCLINATION OF SATELLITE ORBIT
Journal of Astronomy and Space Sciences, volume 10, issue 1, 1993, Pages 17~27
The orbit characteristics and perturbation effects of an artificial satellite with critical inclination have been studied. The critical inclination problem in artificial satellite theory is treated as Ideal Resonance Problem(IRP). The KITSAT-1 satellite launched by Arian 42P at Guiana in August 11, 1992 has orbital inclination close to the critical value cos-1(1/√5). In that case, there is a singularity in some perturbation terms and perigee of the orbit is fixed because d
/dt is theoretically equal to zero. But actually the long periodic behaviour in argument of perigee,
shows a small oscillation. The causes of the oscillation and the relativistic effect in IRP have been studied and applied to the KITSAT-1. The geo-potential perturbation terms which are seperated inclination terms have been obtained using Algebraic manipulation. Also luni-solar disturbing funtion based on the relative position of the sun, moon, and satellite has been obtained. Phase portraits are used to depict the change of eccentricity and grgument of perigee. The variations of each orbital elements have been obtained in case of the KITSAT-1.
INFRARED MODEL SPECTRA FOR EVOLVING RED SUPERGIANTS
Suh, Kyung-Won ;
Journal of Astronomy and Space Sciences, volume 10, issue 1, 1993, Pages 25~35
Stars lose their masses constantly after their birth, but the stellar mass loss is especially prominent in the last stages of their lives. It has been believed that red superginats are losing their masses at rates of 10-8∼10-4M/yr. They are known to be asymptotic giant branch stars that are at the end stages of the evolution for the stars with zero age main sequence masses of 1∼10M. Red supergiants are often characterized by the thick dust envelopes and large amplitude pulsations. According to their energy spectra, chemical composition, they are divided into three main group; M-type Miras, C-type carbon stars, and OH/IR stars. The purpose of this work is to clarify the evolutionary aspects in the physical parameters of the red supergiants mainly from the direct interpretation of their infrared spectra.
LIGHT CURVE ANALYSIS OF SAO23229
Journal of Astronomy and Space Sciences, volume 10, issue 1, 1993, Pages 36~43
We have made UBV light curves of a newly discovered eclipsing binary, SAO23229 at Sobaeksan Astronomy Observatory. We determined a minimum light time of HJD2448636.1170
0.0005 that is 3 minimum later than predicted time, and found a peculiar light variation at phase 0.75 that may not be secondary eclipse. Orbital period of SAO23229 would be 4.2 days rather than 2.1 days. Our analysis of the light curves shows that SAO23229 has a detached configuration consisting of two almost identical F type main sequence stars.
CHARACTERISTICS OF PERIOD VARIATION OF ECLIPSING BINARY STAR
Journal of Astronomy and Space Sciences, volume 10, issue 1, 1993, Pages 44~85
Among the EA and semi-detached type binary systems, nineteen eclipsing binaries were investigated for their period variations from all of the collected times of minima available in the literature. After the period study of each individual binary, an attempt was made, in view of the linear ephemeris showing abrupt change in period, to give a physical interpretation to the combined observational result. The correlation between period changes and physical parameters of the investigated binary systems are discussed.
CORRECTION OF GAS MULTIPLICATION UNIFORMITY OF X-RAY DETECTOR BY VOLTAGE COMPANSATION METHOD
Journal of Astronomy and Space Sciences, volume 10, issue 1, 1993, Pages 86~93
We experiment of the method to obtain the uniform gas multiplication in multiwire proportional counter. The general techenique of anode wire connection for the high voltage supply could not secure the uniformity of multiplication because of the edge effect at the outer anode wires. We found that the variation of the multiplication could be corrected in the accuracy of
1.6% rms using the voltage compansation method.
DEVELOPMENT OF MULTI-CHANNEL PHOTOELECTRIC PHOTOMETER USING OPTICAL FIBER
Journal of Astronomy and Space Sciences, volume 10, issue 1, 1993, Pages 94~102
We have develped a four-channel photoelectric photometer for the 61cm telescope of Sobaeksan Astronomy Observatory using optical fiber. We observed a standard star with each channel to check the efficiency difference between the channels, and found no differences. To calibrate the observing accuracy and efficiency, we have observed a short period W UMa type eclipsing binary star, BV Dra. Test observations show that the photometer is very stabel and the accuracy of the data is also increased. The observing efficiency is very increased compared with that of single channel photometer ; at least five times faster than older one in the case of one filter observation.