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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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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THE INITIAL MASS FUNCTION FOR THE SOLAR NEIGHBORHOOD STARS
Lee, See-Woo ; Chun, Moo-Young ;
Journal of The Korean Astronomical Society, volume 19, issue 2, 1986, Pages 51~62
The Wielen dip over the ragne of 6 <
< 9 in the luminosity function (LF) for the solar neighborhood stars could be explained by the combination of two different IMFs which yields the age of 13 billion years of the solar neighborhood. This smaller age than the Galactic age, 15 billion years indicates the slow collapse model of the Galaxy, solving the G-dwarf problem. Two different IMFs suggest two different mechanisms for star formation in the solar neighborhood.
CAUSTIC AND IMAGE PROPERTIES OF GRAVITATIONALLY BENDING LIGHT RAYS
Chang, Kyong-Ae ;
Journal of The Korean Astronomical Society, volume 19, issue 2, 1986, Pages 63~68
In this paper we deal with the orientation and the deformation of the circular light bundle passing in a static bounded gravitational field. The properties of caustic of the gravitational lens are discussed.
SURFACE PHOTOMETRY OF BARRED GALAXIES.: I. MORPHOLOGY
Ann, Hong-Bae ;
Journal of The Korean Astronomical Society, volume 19, issue 2, 1986, Pages 69~89
The global morphology and geometric parameters of 39 barred galaxies are investigated, by using isophote map and isodensity tracings obtained from detailed surface photometry with the Kiso V-band plates. The observed results are as follows: i) There is no strong indication that the ratio of bar length to disk size is correlated with Hubble type, except that the largest bars appear in the SBb galaxies. ii) The mean value of axial ratios of bars is
and there is a trend that early type galaxies have smaller axial ratios than late type galaxies. iii) About 15% of early type barred galaxies(Sb0-SBb) have triaxial bulges.
STELLAR MAGNETIC ACTIVITY AND LONG TERM LUMINOSITY VARIATIONS OF LATE TYPE STARS.: II. STELLAR ACTIVITY PERIODS BASED ON PARKER'S DYNAMO THEORY
Park, Chang-Bum ; Yun, Hong-Sik ;
Journal of The Korean Astronomical Society, volume 19, issue 2, 1986, Pages 91~107
Making use of our extended version of
convection theory, we have calculated magnetic cycle periods of the sun and late type stars by using Parker's dynamo theory, where we have included the non-linear effect. We presented a relationship between the computed cycle period and spectral type to analyze observed magnetic activities of the late type stars and long-term luminosity variations. It is found that (1) the stellar magentic-cycle period increases towards the later spectral type, (2) the rapid rotation facilitates the activity-related luminosity variation of stars later than about K5, (3) differential rotation plays a critical role in determining the magnetic activity-cycle period, and (4) the non-local effect should be taken into account in order to understand the observed long-term luminosity variations.