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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Astronomy and Space Sciences
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Journal DOI :
The Korean Space Science Society
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Volume & Issues
Volume 3, Issue 2 - Dec 1986
Volume 3, Issue 1 - Jun 1986
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A Study of Current Driven Electrostatic Instability on the Auroal Zone -Based on Particle Simulation Methods-
S.Y.Kim ; H. Okuda ;
Journal of Astronomy and Space Sciences, volume 3, issue 2, 1986, Pages 71~79
According to recent satellite observations, strong ion transverse acceleration to the magnetic field(ion conics) has been known. The ion conics may be a result of electrostatic waves frequently observed on the auroral zone. Both linear and nonlinear theory of electrostatic instability driven by an electron current based on 1-dimensional particle simulation experiment have been considered. From the results of simulation strong ion transverse acceleration has been shown.
Z-Distribution and Period Gradient of Classical Cepheids in the Galactic Plane
Kim, Chul-Hee ;
Journal of Astronomy and Space Sciences, volume 3, issue 2, 1986, Pages 81~92
The z-coordinate distribution of cepheids was studied and the finding of Fernie(1968) that the cepheid layer is inclined to ward a formal Galactic plane and the Sun is located above the cepheid plane was confirmed. It was found that the z-distribution fits better to the parabolic form than a barometric form and a scale height of 54 pc was found. The well known phenomenon that the periods of classical cepheids decrease away from the Galactic center was crudely interpreted as due to an age gradient rater than an abundance gradient under the assumption that relations between the period and galactocentric distance, and between the abundance and period are linear.
Evolution of the Orbital Elements for Geosynchronous Orbit of Commmunications Satellite, I. East-Station Keeping
Journal of Astronomy and Space Sciences, volume 3, issue 2, 1986, Pages 93~102
For a geostationary satellite east-west station keeping maneuvers must control both the mean longitude and the orbit eccentricity simultaneously. The effect on the orbit eccentricity of maneuvers may be reprensented by a phse plane of
, since these eccentricity elements give the projection of the orbit center onto the equatorial plane in units of the semimajor axis. The evolution of the mean longitude and the orbit eccentricity are obtained.
Physical Parameters of Late Type Spiral Galaxies - III. Mass and Mass to Luminosity Ratio of NGC 7793
Kim, Chang-Ha ; Chun, Mun-Suk ;
Journal of Astronomy and Space Sciences, volume 3, issue 2, 1986, Pages 103~116
The mass distribution and other related quantities were calculated by fitting the observed rotation curve(Davoust and de Vaucouleur 1980) to Brandt and Belton's mass distribution model. One of n values for mass model is determined as 1.5(Vm=95
) and two pairs of them are determined as 0.8(Vm = 95
) and 2.0 and 0.8 (Vm = 55
) and 2.0 because of the hump in observed rotation curve. Total masses and integrated mass to luminosity ration are
, and 6.57, 5.33, 5.26 for three cases according to n values. Integrated mass to luminosity ratio in Holmberg radius is 3.44, 3.26, 3.00 in god agreement with the typical value of Sd type suggested by Faber and Gallagher(1979). Presented halo masses which are fifty percent of total masses and halo mass to luminosity ratios given as 75.83, 53.50, 58.75 are values less than Turner's(1976).
Numerical Simulation of Ion Beam Acoustic Instability by Single Ion Beams
Kim, S.Y. ;
Journal of Astronomy and Space Sciences, volume 3, issue 2, 1986, Pages 117~122
The broadband electrostatic noise has been observed in the boundary layer region of the earth's magnetosphers. These electrostatic waves believed to be generated by drifting ion beams in the matnetotail. We have shown the numerical simulation result of ion beam acoustic instability in the magnetotail. This instability heats both background and beam ion in the boundary layer of neutral sheet observed by satellite.