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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Astronomical Society
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Journal DOI :
The Korean Astronomical Society
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Volume & Issues
Volume 19, Issue 2 - Dec 1986
Volume 19, Issue 1 - Jun 1986
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AN OPTIMAL PHOTOMETRIC SYSTEM FOR HIGH RESOLUBILITY OF PHYSICAL QUANTITIES
Park, Nam-Kyu ; Lee, See-Woo ;
Journal of The Korean Astronomical Society, volume 19, issue 1, 1986, Pages 1~9
We present a method for deriving most optimal filter system by which the accuracy of derived physical quantities can be maximized. Using Kurucz(1978)'s model atmospheres, an optimal four filter system for F and G dwarfs is suggested, for which mean wavelengths are located at
with half-bandwidth of
. It is found that 35, 38 and 42 filters of the DDO system and the
filters are close to those of the most optimal system.
ASTIGMATIC PROPERTY OF N-BODY GRAVITATIONAL LENS
Chang, Kyong-Ae ;
Journal of The Korean Astronomical Society, volume 19, issue 1, 1986, Pages 11~14
It is shown in this paper that the astigmatic property of single gravitational lens in static bounded gravitational field can be retained, if n-gravitating body as a whole acts simultaneously as gravitational lens.
INFLUENCE OF CONVECTION ON LINE ASYMMETRIES
Park, Yong-Sun ; Yun, Hong-Sik ;
Journal of The Korean Astronomical Society, volume 19, issue 1, 1986, Pages 15~31
We have analyzed Gray's observed mean line bisectors of FS, G0, G2, and G5 normal dwarf stars and interpreted them by computing theoretical line bisectors based on a two stream model. A set of perturbed models has been derived, and their detailed structures on temperature fluctuations and velocity fields are presented as a function of depth, which account for the observed bisectors. From the present study, it is found that the degree of stellar convective overshootings and temperature fluctuations in the upper atmospheres increases towards earlier spectral types. The convection cell size inferred from these models is found to increase also with the advancing earlier type. We demonstrated the usefulness of line bisector analysis as a diagnostic probe for stellar convection.
DENSITY STRUCTURE AND STABILITY OF THE SUBCOMPONENTS IN GIANT MOLECULAR CLOUD COMPLEXES
Yoo, Chin-Woo ; Hong, Seung-Soo ;
Journal of The Korean Astronomical Society, volume 19, issue 1, 1986, Pages 33~49
Radial distribution of internal density has been determined for thirteen subclouds in the three giant molecular cloud complexes accompanying Mon OB1, Mon OB2 and CMa OB1 associations, We modeled their radial density structures with the density distribution of isothermal gas spheres. Most of the subclouds, nine out of the thirteen, are well described by isothermal spheres of single component; while the rest four require an additional component. Total mass and potential energy of each subcloud are also derived from the radial density structure; thermal energy and internal velocity dispersion required for sustaining the density structure are deduced from the isothermal gas model. Our derived masses of the clouds are comparable to the values determined by Blitz (1978) under LTE assumption. This agreement suggests that the correction factor for non-LTE effect on mass-estimate is not far from unity. The ratio of the gravitational potential energy to the kinetic energy of thermal motion is as large as 250; hence the thermal motion alone cannot support these clouds against the gravity. Being supported by turbulence motion with velocities of six to seven times the thermal velocity, the clouds of one-component type seem to be in equilibrium with the gravity; while the clouds of two-component type are likely to be in the stage of gravitational collapse.